Hempcrete for Brooklyn Brownstone Extensions

We at Eco Brooklyn have been in love with Hempcrete – a mix of lime and hemp for walls – for years. A hempcrete wall provides strength, protection and insulation all in one.

Compared to stick and frame building it uses much less wood and is much more solid of a structure. A hempcrete home feels solid. And the soundproofing qualities are amazing.

The one drawback is that you do need a thicker wall – at least 12′. In space starved NYC this can be a problem. The wall doesn’t, however need any kind of finishing (sheet rock for example) so space is saved there.

We think a Hempcrete application is perfect for a brownstone extension. It is so much greener than the cinder blocks often used. And in terms of comfort it is unmatched. No air leaks or thermal bridges.

Eco Brooklyn is a New York Hempcrete installer. We feel that it has it’s place in the NY green building lexicon. More and more, though, the green building lexicon is simply becoming building lexicon. Green building makes sense.

We are eager to install more hempcrete walls. Even if it is just one wall that acts as a centerpiece, the visual beauty and tactile comfort of hempcrete is makes it practically a work of art. Optionally you can plaster the wall with clay, another beautiful material.

Check out this video on how a hempcrete wall is built. You will notice how very simple it is.

Klearwall Windows and Doors

Eco Brooklyn was visited today by Klearwall Industries. Klearwall is a certified Passive House windows company. Originally based in Ireland, Klearwall is looking to make its mark in the US market. They offer triple-paned windows and doors for domestic and commercial needs, ranging from single-window installation to entire buildings. Their windows are billed as eco-clad, future-proof, and affordable. All of this is with good reason. 

Klearwall boasts an R-Value as high as 9.8hr.ft².˚F/BTU, which results in a 60% to 74% solar heat gain (depending on single or double glaze). Their PVC frame option is guaranteed to last 35 years and is sold at a bargain of approximately $33 per square foot.

Klearwall’s products are designed, fitted, and tempered in Ireland and shipped to the United States. Their plant is one of the largest carbon neutral factories in Europe and is powered solely by renewable energy. They offer a range of products – from windows in all-wood, aluminum, PVC, or a combination. The PVC and aluminum used is recycled from salvage jobs and treated at the plant.

As a pioneer in passive housing, Eco Brooklyn is always interested in companies such as Klearwall for their business strategy and philosophy. We wish them all the best as they try to help make New York a greener place.

Check out their website at http://www.klearwall.com/

A model of Klearwall triple paned window.
A model of Klearwall triple paned window.

Air Sealing in Brooklyn

Eco Brooklyn was recently commissioned to insulate a new development in the Brooklyn neighborhood of Bedford-Stuyvesant. As a specialist in insulation and air sealing we have seen an increase in business from the many new multi unit apartment buildings that have shot up – not during construction, but AFTER construction.
As housing demand has continued to rise in New York City, developers have been driven to build quick, and build cheap. In this process, the basic concept of insulation is bypassed in favor of a quickly constructed shell of a building to show potential residents the physical product, but all too late, residents come to realize that they end up paying enormous utility bills because the units they live in are exactly that – a shell.
new development
A brand new development….
 Insulation contractor
As a Green Builder, energy conservation is an important focus for us. Not only do residents personally benefit from the energy savings (40% of energy costs are due to air infiltration that proper insulation will greatly reduce) and a comfortable sound and temperature controlled home climate, but they put less strain on the energy grid as a whole, which has far-reaching effects for the country and the world.
More importantly, the idea of conservation, to use only what is necessary rather than gratuitously simply because we are fortunate enough to be able to, is a multi-layered concept that is all too easy to forget when one lives in a developed country such as our own. The DOE’s Building Energy Codes Program (BECP) provides a guide for national energy codes.
DOE air-infiltration major sources of air leaks
Major sources of air leaks, image courtesy of the US Department of Energy
The two basic forms of insulation that Eco Brooklyn used are Cel-Pak, a loose cellulose spray, and spray foam.
Cellulose is a green alternative to fiberglass largely because of its mostly recycled content of roughly 85% shredded newsprint that has been chemically treated to resist mold, fire, and pests, without the use of formaldehyde, asbestos, and glass fibers. According to the Cellulose Insulation Manufacturers Association (CIMA), “In 2007 about 3,000,000 tons of newspapers went to U.S. landfills.  This paper could have been used to produce an additional 200,000,000 bags of Cellulose Insulation.  There is enough paper going to landfills to produce enough Cellulose Insulation to replace nearly all other types of insulation.” The manufacture of cellulose as well requires significantly less BTU to produce that standard fiberglass.
A large benefit of loose cellulose spray is the ability to conform around plumbing, wiring, outlets, and vents, allowing for a custom fit uniform thermal barrier for every cavity. It has an R-value of 3.8 per inch, allowing exterior wall designs to reach a higher total R-value. Though this is not the highest, its cost per R-value is low enough to make it a sound investment.
Holes are drillled into the tops of walls and the spray cellulose is blown in until the capacity is reached. There is a tendency for the material to settle up to 20%, therefore requiring that the application be continued after some settling time. In this case, Eco Brooklyn used this method to insulate the exterior walls of the building.
Holes are drilled into the walls and ceiling
cel pak truck
Eco Brooklyn insulated our client’s building with Cel-Pak, a regionally produced insulation alternative.
hose running 1
hose running 2
cellulose spray1
The spray cellulose is blown in by hoses connected to the spray containers filled with the material.
Closed-cell spray polyurethane foam (SPF) is a cheap form of permanent flood resistant insulation that is easily available. SPF has an R-value of 6.0 per inch, which is greatly superior to that of cellulose. However, the environmental impact from its manufacturing is far greater and the adverse health effects caused by its chemical makeup have been brought up by the EPA, and therefore minimal use is preferred. Eco Brooklyn used SPF in the exterior walls and behind the baseboards of the building where moisture has a greater tendency to collect, It’s waterproofing feature is best used here to prevent mold growth. Rockwool is used as a filler to reduce the amount of foam needed, and the openings are covered with cut foam board. Tescon tape provides an airtight, waterproofed seal.
Rockwool provides most of the filler for insulation.
spray foam
 SPF provides permanent dense waterproofing.


ac 1
SPF sprayed around the rockwool creates the greatest insulation for the exterior walls.
ac 3
Foam board is cut to conform around opening.
 tescon tape moisture not air   foam board insulation
Tescon tape is used to seal the seems, providing airtight waterproofing.
foam floorboard1
Holes are drilled into the drywall behind the baseboard.
foam floorboard
SPF is sprayed into the holes.
-Anthony Rivale & Liza Chiu

NJ Contractor Builds Passive House and Creates an Educational Video

Ed from NJ Renewable Energy made a great video about the construction of his passive house that you can view below.  It discusses the many benefits of building a Passive House, the amazing energy savings that are possible and the details behind how they built this specific one in New Jersey.

As a NY Passive House contractor we appreciate his hard work and dedication to sharing the information with the public.

Passive House Video from NJ Renewable Energy

Your Walls Could Be Filled With Mushrooms

As New York green contractors, we’re always interested in emerging innovations, but take special interest in locally-developed technologies because we believe that green solutions should have a local focus.  An effective way to build green is to ensure that each building make the best use of the environment in which it’s located.

In New York state, for example, we have hot summers and cool to cold winters.  Insulation is important for keeping homes at a comfortable temperature while minimizing energy costs.  We also have farmland and woodland…which means mushrooms.

Ecovative Design started out as two RPI students’ mutual fascination with mushrooms. A class project resulted in growing a mushroom-based composite that could replace synthetic materials like Styrofoam.  Rather than lessening the impact of traditional synthetics, Ecovative is introducing radical materials in un-heard of ways.  The innovative start-up is currently growing into one of the most promising manufacturers of green building and packing materials.

We’re mostly interested in their mushroom insulation.

It’s not quite the same as the mushrooms we buy at the supermarket: Ecovative makes their materials out of a mycelium composite.  Mycelium is the thready part underground; fruiting bodies are the parts we see and eat.

Filling your walls with fungus might not sound like such a great idea, but let me tell you why it’s amazing.

Mushroom materials are as safe and sturdy as traditional insulation.  They won’t melt in the rain.  They achieve a class 1 fire rating without needing toxic fire retardants and have very few volatile organic compounds or none at all.  There is no need for toxic adhesives like formaldehyde.  They can be touched and handled with no special protective gear.   There are no spore or allergen concerns, since materials are heat-treated after growing.

That’s right, growing.  Ecovative grows their materials out of farm junk and mushrooms, an upcycling process that reduces waste.  They start with agricultural byproducts, which are then inoculated with mycelium and grown to the exact shape needed by the client.  They’re basically made from an unappreciated waste product (seed hulls, husks, etc) and a renewable resource (live mushrooms).  When you’re done, they can be composted like any other organic material, leaving behind neither chemicals nor waste.

The humble mushroom is a powerhouse.  In Mycelium Running: How Mushrooms Can Save the World, Paul Stamets describes the potential for “mushroom ecoremediation,” in which we take advantage of mushrooms’ natural digestive abilities to clean up organic pollution.  Mushrooms can eat through all kinds of trees and houses like nobody’s business, but they can also digest complex organic particles found in petroleum and other messy contaminants.  Stamets describes an experiment where he watched oyster mushroom mycelia absorb brown gunk, slowly return to its original white, and send up robust fruiting bodies.  In other words, the mycelium ate our garbage, and made extra big mushrooms–more food for us!

But back to mushroom as a building material.  Mushroom materials can benefit builders, clients, and the environment.  They’re efficient by building and safety standards.  They become increasingly cost-effective as petroleum and plastic prices rise with oil prices.  Their production, use, and recycling leave no mark on the environment.

The major downside to mushroom insulation is that you can’t have it yet.  Ecovative’s building materials are currently under development and are not yet for sale.  As green builders, we eagerly anticipate the debut of a locally-developed material that offers homeowners an affordable, safe, and eco-friendly alternative to current methods.

Hi-Performance Tape

At Eco Brooklyn, we do energy-efficiency retrofits that involve huge amounts of air sealing, air barriers, vapor barriers and insulation. We aim for the super stringent Passive House building envelope standard and net-zero energy consumption. This is as radical it gets in energy conservation.
Sealing the home in an airtight shell requires a bit of patience and a lot of tape. You wouldn’t believe the number of tiny pinpricks that managed to perforate our plastic membrane, and their aggregate effect on air leakage is equally surprising.
Currently, there are both European and American companies that specialize in several unique kinds of tape for different stages of the envelope sealing process. Onetape, for example, has a soft fabric edge that allows the builder to plaster it airtight against masonry surfaces like brick walls. Another is made for simple, airtight patching over those small pinprick holes.
At the Harlem Passive House we used products from Siga andPro Clima. We’ve purchased custom tapes through Four Seven Five, a new distributor based in NY. 3M has some special tapes but the European products above are still much better; we hope the US companies will catch up.

Insulation Detail For Exterior Walls

Brooklyn homes were originally built without insulation. We often come across a situation where we are doing a green renovation of a Brooklyn building but not gutting it completely. This creates an insulation problem. We want to add plenty of insulation but that is hard if you are working with existing exterior walls.

In this situation I propose two options depending on the budget: a bare bones solution and a prefered solution.

Bare bones solution:
As a minimal solution we suggest blowing insulation into the walls. We knock 4″ holes into the plaster walls and blow cellulose insulation into the exterior wall cavity. Cellulose is about R4 per inch, and if the space is 4 inches deep then at best you get R16. But the studs pass a lot of heat in thermal bridging. So in reality a blown in insulation wall will give you an R 7 to R 12. which isn’t much but certainly a lot better than nothing.

You then patch up the plaster walls and paint.

(As a side note, when non-green contractors throw in R18 fiberglass bats in between the studs they are fulfilling all code requirements yet building a wall that is closer to R 7, which partly explains why the world has an energy crisis.)

Prefered Solution:

The ideal solution would be to blow insulation into the walls as above then lay an air barrier layer so that no air gets into the house. Then we lay PolyISO insulation board over the air sealed walls. We then apply sheet rock over the insulation. We attach the sheet rock by drilling screws through the insulation board to the studs of the old wall.

This would improve the comfort and energy savings drastically due to reduced thermal bridging and increased insulation. If you use 2 inches of PolyISO the R value of the wall would be 19 to 24 which is a much more acceptable number. The air barrier further decreases air leaks and improves the insulation value even more.

Some insulation specialists would choose to remove the old plaster wall because it is easier to install insulation between studs rather than blowing it into the wall cavity. But then you are sending more trash to the land fill and paying for it. I think it is better to leave the trash where it is. Of course if you really needed the extra R value you could tear down the old plaster and put PolyISo between the studs which has at least two R values more than cellulose. But that is overkill for most jobs.

Below are details of the layers involved.

Insulation Wall detail Frame

Insulation Wall detail Brownstone

Brooklyn Brownstone Extentions and the Stack Effect

This is the season of phone calls from clients needing Eco Brooklyn’s help with their brownstone extensions. The problem is always the same: they are cold.

They call us up because we are Brooklyn brownstone insulation specialists.

Here are my observations having seen and fixed extensions for a while now.

There are two types of extensions. The first was built when the original brownstone was built and its side walls are brick like the rest of the brownstone. It is usually sitting on a thin concrete slab on earth.

The second kind of extension is one that was added on later and is usually built out of wood framing and stucco. It usually sits on a flimsy wood structure a couple inches or a foot off the ground.

Beyond those differences the Brooklyn brownstone extension suffers from the same issues, namely lack of insulation, bad design and bad weather sealing.

The extension is not protected on both sides by neighboring buildings so it has three walls where it loses heat. It is not protected above by another floor and it is not protected below by the cellar or basement. So above and below it is losing heat as well.

All in all the extension is not an energy efficient design.

The other issue is that rarely does the extension have any insulation at all! It is just one massive heat sink.

To make matters worse the brownstone usually has many little air holes all over it’s envelope, from cracks in the cellar to cracks in the brick wall near the roof.

Above: The holes in walls from plumbing and electric are common places for air leaks

These cracks create what is called the stack effect, where hot air rises up a stack. In this case the stack is the house itself.

Hot air escapes out of the cracks in the top floor and roof. The hatch going to the roof, the leaky air space in the attic crawlspace, the cracks in the brick walls around the chimney chute, all these are places where hot air escapes (since hot air rises).

Hot air leaks out to the attic via badly weathesealed drop doors.
Hot air leaks out this attic via badly weathesealed drop doors.

This lost air out the top of the house creates a negative pressure at the bottom of the house that pulls cold air in. The coal chute, the cracks around doors and windows, vents in the boiler room, cellar doors, these are all places where cold air gets sucked into the house.

This cellar door is badly weathersealed and lets in cold air
This cellar door is badly weathersealed and lets in cold air

This stack effect makes the bottom of the house, especially the extension very cold.

Obviously the inhabitants on that floor raise the heat……

And that simply speeds up the process. The boiler goes on overdrive to make more heat, which rises even faster and subsequently sucks more cold air into the house faster.

Eventually the top floors get too hot and somebody opens a window. This speeds it up even more, the boiler works harder, the heat rises faster and the lower floors get colder.

stack effect
Above: The stack effect on a leaky Brooklyn brownstone

And all the while money is being wasted in fuel bills to heat the air ABOVE the building.

The solution?

Contrary to what the clients think, insulation is not the lowest hanging fruit. Sealing the leaks is the first line of action. But people often don’t even realize the house is leaking.

A trained eye or a thermal imaging camera can see the leaks easily, though. For example the image below shows the blue spots where cold is seeping into the house:

Red is hot, Blue is cold. The window and sill is leaking.
Red is hot, Blue is cold. The window and sill is leaking.

To address this issue you need to do weather sealing on the house. With caulk, foam, tape, plaster and weatherstripping, the weather sealing expert combs the house with a scientific eye in search of any place where air can move. Anyone can do this but I trust somebody who really knows what they are doing to do the job well.

Once the air movement has been stopped it is amazing how much more comfortable the house it.

The next step is to insulate the extension. Above, below and on each side it must be insulated as best as possible. In the walls and ceiling it is easy to open up holes in the sheet rock and blow in cellulose insulation.

The ground might be more difficult to solve. If there is a crawlspace then you either staple up fiberglass under the rafters or lay a vapor barrier on the earth and blow cellulose onto the barrier.

If there is no crawlspace and the floor sits on the earth then there are two solutions. One is to dig out the floor a foot, add vapor barrier, 4 or 5 inches of XEPS waterproof insulation, a concrete slab and then tiles.

Variations on the above is to put an earthen floor instead of concrete. Earthen floors can be made so they are very resistant to wear. They are more aesthetically pleasing than concrete, have a warmer more homy feel, and they can serve as the main floor instead of tiling it over.

Above: An Earthen Floor For a Brooklyn Brownstone

Another option is to put radiant floor heating, either in the concrete or the earthen floor.

The second alternative to digging down is to simply build on top of the existing floor. This is slightly cheaper but you can only do it if you have the head room. In this case you add a vapor barrier, insulation, stringers and plywood. You can cover the plywood with wood or tiles.

Once the house has been weathersealed and the extension has been insulated your heating bills go down and the comfort goes way up. The extension no longer feels like an ice box while the people on the top floor are sweating their butts off.

Brooklyn Green Brownstone Renovation Template

The way Brooklyn brownstones are currently renovated does not work. It does not work for the environment nor for the inhabitants’ comfort and utility bills.

Eco Brooklyn is focused on redefining how a brownstone gets renovated. We use the Brooklyn Green Show House as an example of a renovation template that works for the triple bottom line: People, Planet, Profit.

I think all contractors in Brooklyn need to change the template of how a brownstone is renovated. The current template does not work and we’re screwing ourselves and the planet each time we renovate like this.

Here are some basic outlines that Eco Brooklyn follows in our green brownstone renovations. It is a template and anyone can do it.

> Only renovate what you have to
> Only buy what you have to, salvage everything else
> Never buy new wood. Yup, seriously
> Lots of insulation, and then more insulation
> Excellent windows and not too many (even consider closing up north facing windows)
> Airtight, like obscenely airtight
> Controlled ventilation preferably to every room
> Most efficient lighting and appliances practical
> Direct largest proportion of modest window area to the south
> Add the lowest cost and lowest pollution heating source (eg that usually is not electricity but can be in some situations)
> Green roof if possible
> Gray water if possible
> No concrete in front or back yard
> Build It Forward, aka build for a hundred years
> Did I mention insulation?

EPA discusses Spray Foam

A few weeks ago the EPA held a webinar on the safe use of spray foam insulations titled “What You
Need to Know About the Safe Use of Spray Polyurethane Foam (SPF)”. We at Eco Brooklyn are not crazy about spray foam so we watched what the EPA had to say closely.

Their view in a nutshell is: more information is needed and it isn’t as safe as people make it out to be.

Their presentation was a good non biased overview of spray foam and what is needed to make it safer. They have some good info (although not exhaustive). You can view the full report and slide show online (links below).

Key points from the presentation:

  • SPF is one of the fastest growing products in building and construction
  • Companies make misleading marketing claims: “No off-gassing”, “non-toxic”, “safe”, “green” and “environmentally friendly”, “is plant-based”, “made from soy beans”
  • The ingredients of spray foam and their side effects:
  1. Amines (catalysts) – sensitizers; irritants; can cause blurry vision (halo effect).
  2. Flame retardants – some are persistent, bioaccumulative, and toxic
  3. Blowing agents – global warming potential and other considerations
  4. Isocyanates – cause asthma and are the leading attributable cause of work-related asthma. Isocyanates are potent lung and skin sensitizers (allergens) and irritants. Isocyanates can trigger severe or fatal asthma
    attacks in sensitized persons at low levels.
  5. MDI – a hazardous air pollutant – Clean Air Act. NIOSH issued an Alert in 2006 to prevent MDI exposures for a similar spray application. The European Union has issued new regulations for consumer products containing MDI.
  • Long term stability of polyurethane foam:
  1. Fully cured polyurethane foam is not considered a problem unless disturbed.
  2. Heating, welding, or grinding generates free isocyanates and other hazards.
  3. Fires and thermal degradation can generate and release hydrogen cyanide, carbon monoxide, amines, and isocyanates.
  • Alternative Technologies are:
  1. Fiberglass, cotton, and mineral wool batts.
  2. Fiberglass and cellulose mixed with an adhesive can be wet sprayed into wall cavities and have an R-value per inch similar to low density SPF.
  3. Polyisocyanurate rigid foam boards can have similar R-values per inch as high density (2 lb) SPF.
  4. Cementitious and tripolymer foam products can be poured into walls or behind special netting.
  5. A new class of hybrid non-isocyanate polyurethanes (HNIPU) in development

The “112” page presentation is available on EPA’s Design for the Environment site:

Or, here is the direct link to review or download the pdf of the slides:

At Eco Brooklyn our own experimentation on green brownstone renovation shows the same thing the EPA says. We actually find Polyisocyanurate rigid foam boards (PolyISO) to be a BETTER alternative than spray foam. They can be sealed at the seams to create an effective insulating and air barrier.

We use salvaged PolyISO that is in good shape and otherwise would go to the landfill. This means that not only are we not using up new resources but we are making energy efficient brownstones that literally REMOVE garbage from the landfill.

Space is a big issue in brownstones and that is why the high R value per inch of PolyISO is so great for walls. In the floors and ceilings where there is more space we like to use cellulose insulation. Again it is a recycled product without the off gassing and petrochemical issues of spray foam.

The dust is a problem with cellulose, and we don’t know much about the dyes in the paper although we suspect current newspapers don’t use heavy metal dyes like they used to, but we like to think that is only an issue during the day of installation since we try to make sure the cellulose is contained behind the walls. The benefits of cellulose outweigh these comparatively minor considerations when you compare them to the health and ecological impact of spray foam.

Cellulose Insulation Installation

Here is a great powerpoint on how to blow in cellulose into a wall. There is a real trick to doing this. Your generic blower rented from Home Depot does not have the power needed to dense pack to 3.5 pounds per cubic foot. But there are ways to work around this.

Check out the Dense Pack Cellulose Installation File.

We are insulating an entire house in Brooklyn right now and the tutorial was helpful to us, and we consider ourselves seasoned cellulose installers of Brooklyn brownstones. One of the main things is understanding how to use the blower to blow through the cracks in the house so that the cellulose dust fills them. You achieve this with a hole, among other things.

Types of Insulation

Here is a great diagram of all the possible types of insulation, their R value and their environmental impacts. As green builders in Brooklyn we have specific needs. Doing a green renovation in a Brooklyn brownstone requires sound proofing in the walls and ceilings and lots of insulation that takes up little space on the exterior walls and roof.

My favorite is cellulose and salvaged PolyISO for these two needs.

Cellulose is great at soundproofing as well as being insulation. In the ceilings where you have a little more room you can put cellulose. It is recycled and has a million times better environmental impact than fiberglass which is also a good soundproofer.

In the exterior walls of the space craved Brownstone I like salvaged PolyISO. It is the highest R value per inch out of the insulation. On the exterior walls we are pretty fanatical about insulation – at least R 36 – and we can do that with only 6 inches of insulation. When we can we go up to 7.5 inches and get a whopping R 45. For the same reason we use PolyISO in the roof wheresound is not the issue and you just want to pack the R value is. There we try to go to R 90 with 10 inches.

And since the PolyISO is salvaged it is definitely the greenest choice in insulation.

On all the exterior walls and roof we also use reflective aluminium as a radiant barrier. You need to give it at least 1/3 inch of space to work. It is placed on the inside of the house near the sheet rock since Brooklyn is not a hot climate. If it were then the barrier would be on the outside. This has to do with where condensation collects. We use non-perforated aluminium taped well at the seams so it also acts as a vapor and air barrier.


Insulate and Weatherize Book

The book Insulate and Weatherize is published by Taunton and is part of their Build Like a Pro Series – Expert Advice From Start to Finish. It is advanced weatherization and insulation techniques for a residential home in the North and Mid East United States.

This book, like all Build Like a Pro series, is geared towards the handy DIY homeowner or small general contractor. It is expert advice to the expert or near expert home builder. We are pretty educated Brooklyn green builders. We take lots of classes, read lots of books and have been building for years, and we found this book helpful in our quest to create the perfect Brooklyn green brownstone.

The reason is that this particular book focuses on possibly the most effective and green approach to green building: insulation and weatherization. No other aspect of home building and remodeling gives you more effective returns in energy savings and comfort for the dollar invested. It is very much the low hanging fruit and this book really helped us remember that and refine the skill.

For very little money it is possible to insulate and weatherize a home, be it a Brooklyn brownstone or a cape cod frame house, and notice real changes in the monthly energy bills and overall home comfort.

Esencially the book focuses on the simple concept of, “find hole, seal hole.” And then it replicates that many ways with lots of nice pictures and side notes on how to do it best.

In terms of your time, this book is one of the best uses of it if you want to learn concrete green building techniques that show a real change in building renovation.

Of course for good contractors these skills have always been there and were never called green, they were just the right way to build, but now that the green revolution is upon us these techniques have been thrown in the forefront of the movement.

And for good reason. For example here in Brooklyn, where we have old Brownstones with cold brick walls and drafty attic crawlspaces, energy conservation is so important if you don’t want to freeze in the winter and bake in the summer. It is more important than Solar PV, condensing boilers, low e windows, green roofs or chickens in the back yard. If your house is not a super efficient tight envelope you are wasting time and money.

So even though the Insulate and Weatherize book does not talk specifically about Brooklyn brownstones, it is easy to apply their technique to improve the quality of a Brooklyn brownstone.

It is easy to do: Just find the hole and seal hole.

Buy some spray foam, some caulk, and a bag of cellulose insulation and you are half way there. Then just go around finding the holes and plugging them up. If it is a small hole use caulk. If it is slightly larger us spray foam. If it is a large hole like an uninsulated wall studd then use cellulose insulation to fill it.

It really is that simple. It may not be sexy like solar PV and a green roof but like any woman in high heels will tell you, the alure of sexy fades real quickly if it is expensive and uncomfortable. What you eventually want is a nice pair of sweat pants and insulation and weatherization is the pair of sweat pants for the house.

Then, and only then, can you focus on big ticket items like condensing boilers, new windows, whole house insulation retrofits etc. And the book talks about that too.

It is a good book and something you will refer to more than once because of its useful instructional value in specific situations. Want to know the best way to seal a window? The book tells you. Around a pipe? Chapter Two.

Spray Foam – Bad

Here is an email from a fellow green builder, Keith Winston, on the cons of spray foam. No matter how great they are for sealing, they have too many drawbacks IMO. The same sealing can be done with good tape, vapor barriers and caulk.

His email:
The foaming agents of small cans of foam (i.e. Great Stuff) are isobutane or propane. The foaming agents of proportioner-applied spf is the effect of heat, ambient moisture, etc (that is, there are no added gaseous foaming agents, either flammable as above, or refrigerants — see below). The foaming is done by a combination of a heated hose, pressure developed by pumps, and the mixing process (if anyone wants to give me more gory details about this part, I’m all ears). The trade-off is a big, expensive, somewhat delicate instrument called a proportioner, that takes up a truck or large trailer by the time all is done.

The other option are variations of refrigerant-blown foams: the “builder-packs” of foam, of say 600 sf, that come in (2) 5 gallon propane-style tanks (parts A & B), or in much larger 50 gallon compressed tanks etc. These are horrible, in my opinion, since these refrigerants (with high Global Warming Potential, though low Ozone Depletion Potential) are (by design) released 100% into the atmosphere during application. It can be the equivalent of several tons of CO2 for one kit.

I suspect that these are one of the fastest growing segments of the construction foam industry. I’d encourage people to try to get the word out and discourage use of these kits.

Cancer and Fiberglass

In my ongoing awakening, this week it was all about fiberglass. It made me realize that I. who considers myself an advanced Brooklyn green builder, have a lot to learn (May I never forget).

So here I am thinking that fiberglass is relatively harmless as long as you get out the Formaldehyde. Sure fiberglass is irritating because it itches, and it has high embodied energy, but it’s not deadly or anything…..think again pal.

In this case it was one of my clients who is educating ME. The great thing about being a green contractor in Brooklyn is that you attract green clients who often have a lot to teach. They have done their homework and have their own perspective.

Here is an email from one of them today regarding our ongoing conversation about fiberglass. She writes:

Check out the link is on the home page of the below link. You;ll see that they also sell medical info pack for $25, as well as a “Keeping Warm and Staying Healthy” pamphlet from NRDC (“popular and controversial”) for $10 (which I ordered but probably won;t get here in time).


About the Medical information packet
Actual research and analysis from OSHA, NIOSH, the German federal government and others. Includes exclusive translatoin of “Threat of Cancer Through Artificial Mineral Fibers at the Working Place and in the Environment” by the German Federal Health, Labor and Environment agencies, plus fiberglass epidemiology and toxicology, formaldehyde health risks and more. This is the information the Fiberglass Industry does not want you to have!
$25 in the U.S. and Canada; $35 elsewhere

About Keeping Warm and Staying Healthy
Researched and written by the Natural Resources Defense Council. This popular and controversial report is currently available only through FIN.
$10 in the U.S. and Canada; $15 elsewhere

A two-page summary of this report is available here:

From Victims of Fiberglass FAQs page:
“The fiberglass manufacturing plant in Sarnia, Ontario, Canada was one of the dirtiest. An epidemiological study in the mid 1980s showed Sarnia fiberglass workers’ lung cancer rate to be roughly double that of the general population. The plant closed in 1991, but the workers are still sick. The Occupational Health Clinic for Ontario Workers (OHCOW) has been helping former Owens Corning Fiberglas workers from Sarnia with workers’ compensation claims. OHCOW wrote a report about its experiences and the knowledge gleaned from these workers.

Li Fellers contacted us in 1994, while working for ABC television’s 20/20. A determined researcher, Li gathered leads and went to work. Less than a year later, she claimed to have found, among other things, a “smoking gun.” ABC television refused to produce her story. In 1996, Fellers surfaced at the Washington Post, where she teamed up with writer Peter Perl to finally tell her story. It ran on June 22, 1997.

John Bowers of the Healthy House Institute has written an extensive article about the hazards of fiberglass. He cites case studies and other interesting statistics. Read it here. (A LINK)

In June, 1994, the Seventh Annual Report on Carcinogens was approved by the U.S. government. This document listed glass fibers of respirable size as a substance “reasonably anticipated to cause cancer in humans.” The fiberglass industry had lost a highly visible battle over their product. But that does not mean the war is over; far from it. The Ninth Annual Report on Carcinogens was just released; read what it has to say about fiberglass.

OSHA names mineral fibers a health hazard priority. Synthetic mineral fibers are one of 18 groups of substances picked by OSHA as a priority for action. Robert Horowitz of Victims of Fiberglass nominated mineral fibers for the priority list in 1994.”

Gennaro you are not the first to see the ancestry of asbestos in the fiberglass industry.

Cost of Fiberglass, Cotton, Cellulose, Foam Insulation

All costs based on R30 for one square foot.

Johns Manville Formaldehyde free fiberglass $0.60
Ultra Touch Cotton $1.57
Cocoon Cellulose $0.42
Spay Foam – $6.98

The spay foam is based on one inch thick costing $1.62 and having R7. Thus R30 is the crazy price of almost 7 bucks.

Clearly Cellulose is the winner. BTW it is the winner by far in terms of low embodied energy. We always recommend cellulose when possible to our clients. Sometimes it is not possible:
client is allergic to it
we need more R value per inch (in which case we pick salvaged PolyISO that has R6 vs. R4 for cellulose)
it is a humid or wet area (then we pick XEPS).

We don’t see any reason to recommend Fiberglass or Spray foam. One probably gives you cancer with the small shards of glass and the other is a petrochemical and poison mix (spray foam has Isocyanate)

Is Fiberglass the new Asbestos?

I am having a hard time finding studies for or against the health impact of fiberglass, specifically the little glass fibers in peoples’ lungs.

Here is a little conspiracy theory I am thinking up as I write:

The big companies that made asbestos told everyone it was safe. Then they all claimed bankruptcy when the lawsuits started piling in so they wouldn’t have to pay them. This is pretty well documented.

But where did those companies go? Where did the managers go? Did they all change careers and work at Burger King?

These are companies and people who know insulation.

My guess is they started new companies selling insulation. Only this time they picked less troublesome (for them, that is) material like…..fiberglass.

I’m not saying Fiberglass is a major hidden form of cancer and that the big companies are keeping it under wraps.

I am saying that they did it once with asbestos. And my common sense tells me that prolonged exposure to little glass needles is going to do damage to the lungs….yet the companies claim it won’t…..my little bullshit radars are buzzing a little.

I’m not coming to any conclusions but I’m going to stop recommending fiberglass to my clients. I only recommend formaldehyde free fiberglass and only when the client has allergies to cellulose. But from now on I will recommend the more expensive cotton insulation instead formaldehyde free fiberglass.

Embodied Energy Of Insulation

When buying insulation for those tired Brooklyn and NY brownstones one of the big considerations is the embodied energy the insulation has.

The May/June issue of Home Energy Magazine has a great article where they discuss the various types of insulation.

In the article they lay out their findings on the embodied energy of the main types of insulations:

Cellulose – 600 Embodied Energy/ft2 at R-20 in BTU
Fiberglass – 4,500
Spray Foam – 14,000
Rigid Board (EPS) – 14,300

Cellulose blows the others out of the water in terms of low embodied energy. Spray foam and foam board are off the charts on the other end. Fiberglass sits in the middle somewhere.

Something to keep in mind when choosing insulation: to not only choose the most healthy but to also choose the one that has least impact on the planet. According to this article cellulose is clearly the winner.

Insulating a Brooklyn green brownstone

I went by a house renovation the other day. They were doing all sorts of fancy stuff – especially a super high end radiant floor heating installation. And then they were putting in 3 1/2 inch fiberglass insulation for the exterior walls.

From the perspective of a green brownstone builder that’s like ordering a really expensive meal and garnishing it with ketchup packets you stole from McDonald’s. You wasted your money since it’s just going to taste like fast food anyway.

And the same goes for them. Radiant floor heating saves money because you don’t have to heat the house as much. But their utilities are still going to be higher than necessary because they are throwing away all the great heat from those expensive radiant floors through badly insulated walls.

The contractor on the job knows what he is doing and by all “normal” standards he is doing a great job. He is doing everything right. But he is building by non-green standards.

Non-green standards are about comfort in a world where fuel is cheap and America is great. Those radiant floors will feel great under foot. The client will be happy and compared to the previous house that had bad insulation WITHOUT radiant floors he might even see his utility bill go down a bit.

But green construction standards require MUCH more insulation and have much higher expectations towards lowering fuel bills.

My rule of thumb is to insulate by your latitude. Brooklyn is at 40 degrees north. Thus your Brooklyn brownstone’s exterior walls should be R40.

That’s a lot of insulation.

But what’s cheaper, three thousand dollars of insulation now or ten thousand dollars over the next ten years? As anyone who feels the clock of time ticking will tell you, time flies. Don’t invest your money in your utility bill. It’s really a crappy way to save for retirement.

Fiberglass takes up too much space so you have to go with PolyISO if you can find it recycled. Otherwise dense packed cellulose is good but still takes up space. If you don’t have qualms about using so much fossil fuel and have money to burn then spray foam is also great. If you really have money to burn then you can used cotton batts.

The way we are doing the Brooklyn green show house is with three sheets of R9 poly ISO. Each sheet is 1.5 inches thick so that is 4.5 inches of insulation with a total R value of 36. There are 12 inches of brick but that has minimal R value. This site says that each 4 inch brick is about half an R value so 12 inches would be R3.

That makes our walls R39.

But we are also doing a radiant aluminum foil heat barrier which doesn’t add R value but does stop heat (I know, that sounds strange).

In cold climates you want the foil to be on the inside of the house just behind the sheet rock. That way it radiates the heat back INTO the house. In warm climates you want it just behind the outside siding so it radiates the heat AWAY from the house.

One issue with radiant heat foil is that condensation can form on the cold side of the foil. That is in the wall and can cause mold issues. But in a super insulated house that issue is greatly reduced since the heat difference on each side of the foil is minimal.

If the house wasn’t insulated there would be a big difference in temp on each side of the foil and just like a glass of water with ice “sweats” so would the foil.

Another crucial issue with the foil is that it needs at least half an inch of air on one side of it. Otherwise it isn’t able to radiate the heat back and it actually becomes a conductor of heat and as you know metal is a great conductor of heat.

The foil is NON-perforated, meaning it has no micro holes in it that companies put into it so that it breathes. Non-perforated foil also doubles as a vapor barrier. We don’t need it to breather since we are supper sealing everything. The plan is for no humidity to get in there in the first place.

You either build to let things breathe (with natural materials like clay for example) or you don’t and you have to be damn sure which way you are doing it. If you mix the two styles you have serious humidity issues.

Along the same lines we put tar paper in the mix to seal the wall even more from the elements.

And one last thing. Normal construction calls for insulation to be put BETWEEN the studs. This is like putting on a nice warm jacked that has strips cut out of it. Those strips are going to feel cold if you go outside.

The studs are also pretty good at passing cold through. Wood is an ok conductor of heat. Metal studs are great conductors of heat.

So to break that we put insulation sheets BETWEEN the studs and the brick wall. Or we put it OVER the studs. Or we do both. Basically we mix it up because we’re still exploring the best way. But the bottom line is that there is nowhere where cold can pass through any hard surface all the way from the outside to the inside. It will always eventually hit insulation.

First we seal up the bricks really well with cement. They have had a hundred years to deteriorate so the cement seals cracks and strengthens them. Sealing cracks is VERY important because you want everything air tight.

Then we put the tar paper on. This stops any major leaks. We tape and caulk it to make it a vapor barrier of sorts. The tar paper is dunage. Dunage is material that is damaged and the store can’t sell. So instead of throwing it out they give it to me or sell it for pennies on the dollar. They are happy to be rid of it without paying the dump truck to remove it.

Then we put a layer of insulation. The insulation is salvaged from another building.

Then we put the studs. They are salvaged wood that we cut down to size. We also foam seal any large gaps in the insulation. Other times we use tape. We cut the insulation to size and pack it in tight to minimize air holes.

Then we fill the studs with insulation.

The studs are half an inch thicker than the insulation so that when we put the insulation between the studs, the studs stick out half an inch. This allows us to put the foil over the wall and it creates an air space of half an inch.

Then we put the sheet rock over that right at the end. We caulk the sheet rock and paint it to form one final seal.

These walls aren’t letting in ANYTHING!

The temperature in NY changes steeply day to day but inside the house the temperature will remain steady. The insulation will keep us insulated from the swings of temperature. The heater will hum along at a low setting and never really have to move up or down. Of course to make up for the super sealed walls we will need to ventilate the house. We can’t rely on normal house cracks for it to breathe.

But that is a whole different story….

Soy Based Spray Foam

Spray foam insulation is good because it creates very good seals. You don’t have to worry about air leaks.

The one thing it has against it is that it is petroleum based. There is a company that sells itself as a green alternative because it uses soy based oils instead. Biobased is one such company.

I think that is great and even if it only used a small part soy and the rest petroleum it is better than nothing.

I did have a problem the other day with them. I was discussing with them the possibility of me being a distributor and installer for them. I was excited until I asked what % soy they used. For me this is a key point. THE key point. It is what sets them apart from the rest. It is what makes them greener than the rest.

But they refused to tell me and told me that it was “proprietary information”. ????? Your main selling point is proprietary information? And in the same sentence I was told that I shouldn’t worry about that since using their product can get you LEED points.

Then alarm bells went off for me. Their implication was that getting recognized as green via the LEED points were what mattered. The actual ecological benefit, if any, of the product was not important and a secret.

I protested and the sales rep said he’d get back to me. That was a long time ago. He’s not getting back to me.

Like I said, even if it was 1% soy based and 99% petroleum I would choose it over a 100% petrolieum based foam. 1% is better than nothing.

My problem here is the greenwashing they are doing. Green, if anything, is first and foremost about honesty. And maybe they will get back to me and all will be good. But so far my phone is not ringing.

Another thing is the product itself. I bought some cans of the stuff from home depot. I also bought some “Great Stuff” spray foam. I tested them side by side and the Biobased foam failed. It might have been the cold but it dried dry and crumbly. In comparison the Great Stuff dried like hard chewing gum.

This is very important because the foam is used to fill cracks. Cracks often expand and contract. The Great Stuff has an elasticity to it that the Biobased does not. Also, I forsee the Biobased foam deteriorating and becoming dust over time.

I emailed the same rep asking if the cans they sold at Home Depot contained the same ingredients that pros install but got no answer. We had a polite professional relationship so I’m baffled why he didn’t respond.

Here are the pics:

Great Stuff foam is like hard chewing gum when touched:

Biobased foam crumbled when touched. This could be because it was cold when we installed it. But Great Stuff was installed exactly at the same time in the same environment. Biobased foam:

Sound Proofing and Heat Transfer Subfloor

We have a floor with a high ceiling which means we can lay the pex tubing on top of the subfloor instead of hanging the tubing beneath. The pex tubing takes up valuable space and you can only lay it on top of the subfloor if you have the ceiling height.

Having the tubing on top is better because the heat does not have to pass through the sub floor.

We laid stringers of wood 16 inches on center over the sub floor. They were about one inch high.

We put a look of pex tubing between the stringers.

Then we covered the tubing with a mix of sand and structolite. This dense mass was added around the tubes for two reasons.

One it creates a good sound barrier between the two floors. And two it pulls the heat out of the tubes and into the room.

Structolite is a mix of plaster and perlite. Perlite makes it very light which is important since it is a wood joist floor. Perlite is also a good heat insulator, which is bad since we want the mass to pull as much heat out as possible. So we mixed it with sand which is a good conductor but heavier. It was basically a balance we had to find between weight and conductivity.

We dry packed the mixture, meaning we used barely any water at all and packed it in manually instead of pouring it. Wood flooring is going over it so we didn’t want a wet mix that would take a long time to dry.

The end result is a nice warm floor that stops sound between the two apartments. Price was also a consideration. Sand and structolite are very cheap yet very effective in their uses here. The labour was a consideration since it took time to pack the mix in. But it still was much cheaper than any other combination that I can think of.

One important point is that we did not put any tubes or mass near the walls. Instead we put insulation. This is to keep the heat inside the house and create a dense insulation barrier between the heat and the cold. This keeps the house warmer and with a lower heating cost since less heat is lost to the outside.

Applying Cellulose Insulation

I had an in depth talk with the lead technician who makes Cel Pac, one of the cellulose insulation manufacturers. I was discussing with him the topic of dense packing cellulose so that it does not settle and leave air pockets in the top of the walls. They suggest packing it to 3.5 pounds per square foot which is the same as putting a 3.5 pound 12’x12′ tile over a square foot of it.

The professional blowers have enough air pressure to create that packing density. The problem is that the local rental places sell blowers that are only made to blow the stuff into attics where dense packing is not needed and thus the blowers do not need to have pressure. And also they are usually used and abused which lowers their pressure further.

Since I didn’t want to invest in a $8k professional machine yet I was asking him about ways around the problem.

I also wanted a way around buying the par pac netting that you attach to studs and use to hold the cellulose, which would be an extra cost and also add a lot on the install time.

So I asked him a question that I wasn’t sure if he was going to hang up on me or answer:
“What if I put the sheet rock onto both sides of the wall and leave a space at the top. Then I fill the space with cellulose and pack it down with a two by four! Would this be crazy or would I achieve the same effect as par pack netting and an $8k machine?”

To my happy amazement his answer was YES! I thought that was just wonderful. I had found a solution that was low tech, effective, and affordable. That for me is green!

Inserting the Insulation Into the Roof Ceiling

We are inserting the salvaged poly iso insulation board into the top floor ceiling of the house between the joists. All the joists have been sistered with “new” salvaged joists. You can see the bolts holding them together. We are packing four layers of poly iso board, making it an air tight R 36. The roof insulation is obviously the most important in terms of insulation so we are making it very well insulated.

Below the insulation will be a radiant barrier of aluminum foil that will reflect back the heat into the building. On top of the roof will be two inches of waterproof extruded polystyrene insulation board and then the earth for the green roof.

After all this, the roof will be very well insulated, probably close to R 50. Since the Poly ISO is salvaged from another job it is very cheap so we are using as much as we can possibly fit into the space. It is the same Poly ISO we are selling on the main page.

inserting polyiso insulation into the ceiling
Above: inserting polyiso insulation into the ceiling

Below: you can see the poly iso has all been inserted. You can also see the joists. On some we have added two more, making three sistered joists in some places. These joists are each 3x8 inches thick. We did this to make the roof as strong as possible to carry the green roof. It should last another 100 years.

Choosing Green Insulation – consider recycled foam board.

In the constant quest for a greener insulation I have considered many options.
– Cellulose is good but messy and dusty.
– Isonyne spray foam or Demilec spray foam is good but not that cheap and quite honestly not as green as they say. It takes huge amounts of energy and petroleum to create the main ingredient isocyanate.
– Formaldehyde free fiberglass is ok but still fiberglass (scratch, scratch).
– Solid foam is good and in my opinion under valued by the green community.

THEN you have RECYCLED SOLID FOAM, which I am starting to think is the way to go.
It comes out at the same price as normal fiberglass batts but is way better R value when you air seal the boards correctly. And it is RECYCLED.

In my opinion normal (non-green) recycled materials is better than new green material. Why make more when it has already been made.

ALSO, foam board does off gas a little BUT almost all of that happens in the first few months or year. And since it is recycled it has already off gassed! Now that is a fantastic side benefit of recycling!

Further info I found on the web

Whether it takes the form of batt, loose fill, sprayed-in foam, or rigid foam, insulation is an essential part of any housing. Insulation slows the transfer of heat (energy) from warmer areas to colder areas. It can also serve to reduce noise. Insulation effectiveness is typically measured in R-value. A higher R-value for insulation is better. A well-constructed insulation system will help reduce air infiltration and heat transfer and help control moisture. All of these factors need to come together to produce a comfortable and healthy living environment. The following analysis examines the relative economic, energy, and environmental impacts of the following insulation types: fiberglass batt, blown and loose fill cellulose, blown fiberglass, foamed-in-place polyisocyanurate or polyicynene, extruded polystyrene, expanded polystyrene, and rigid polyisocyanurate.

Loose fill, blown and batt insulation is more cost effective in walls and attics than rigid board insulation. Foamed-in-place insulation should be used when budget permits, its high R-value combined with excellent air sealing increase the overall performance of the assembly. Look for insulation materials that have stable R-values over time.
Extruded polystyrene (XPS) insulation with CFC or HCFC’s as blowing agents should not be used. Rigid insulation alternatives include: wood fiberboard, (some made entirely from recycled cellulose), expanded polystyrene (EPS), fiberglass board, or cellular glass board.

Insulation Fact Sheet:


cost/sq. ft./R (materials & labor)

energy (R- value per inch)


expected product life (years)

life cycle thinking


fiberglass batt







cellulose blown and loose fill







fiberglass blown







foamed-in-place polyisocyanurate
or polyicynene

not available





requires trained installer

rigid perimeter: extruded







rigid perimeter: expanded







rigid perimeter: polyisocyanurate







Criteria Summaries
Cost: Loose fill, blown and batt insulation materials have a low cost per R-value and rigid board materials. Higher first costs associated with increased insulation thickness of any type may be recouped over the life cycle of the building through reduced heating and cooling costs. Premium costs associated with insulation with higher R-values per inch not only reduce operating costs but also use less material.
Energy: Rigid insulations typically have a higher R-value per inch than batt or blown insulations.
IAQ: If left undisturbed in wall cavities and attic spaces insulation poses no threat to human health. Respiratory masks should be worn when handling fiberglass and mineral wool batts, since they may potentially release fibers into the air during handling.
Expected Product Life: The R-value of most insulation materials decreases with aging. Polyisocyanurate and polyicynene have the longest expected life with the greatest R-value stability. Loss of R-value can be attributed to several different factors. Batt insulation can slump in cavities, or become damaged by moisture. These effects can be limited by proper construction and detailing. Rigid insulation can shrink and or dry over time, while loose fill insulation can settle, decreasing its effectiveness.

Life Cycle Thinking:
• Energy consumption (non-renewable, fossil fuel energy): The manufacturing process for fiberglass and mineral wool batts is energy intensive although less than for rigid products. Where recycled content is higher, energy impacts related to manufacture are further reduced. Rigid insulations have high embodied energy from extraction through production, though they offer higher R-value per inch thickness, and require less material overall.
• Pollutants generated in production: Extruded polystyrenes still use HCFC’s, while expanded and some polyisocyanurates use alternative agents.
• Potential for off-gassing: Not an issue when insulation is not exposed to the interior.
• Durability of the product: Prolonged contact with moisture can cause the paper backing on batt insulation to deteriorate, and also mat down batt and blown insulation, reducing the effective R-value of the material.
• Potential for future recycling: Blown insulation suffers from settlement, but can be recovered easily for reuse. Certain expanded polystyrene rigid insulation products use recycled content in their products (or at least reused waste products).
Practice: With the exception of sprayed-in-place insulations, which require training and professional installers, all insulation types are considered common practice.

Environmental Context
Reducing the amount of fuel to heat and cool also reduces environmental damage and costs. Insulation effectiveness is usually measured in R-value (thermal resistance) – the higher the R-value, the better the insulation value. Other considerations include the amount of recycled content, the ability to reuse or recycle the insulation, the ability to meet code requirements (in Minnesota amendments to the Uniform Building Code and the residential building code), and off-gassing of the products in place. Batt and blown insulation materials will generally have lower embodied energy than rigid insulation materials.

Here is some more info on Rigid Foam Board Insulation from my research

Rigid foam board insulation is a popular mass insulation product used to insulate all parts of homes, metal buildings and commercial buildings against the movement of conductive and convective heat transfer. A high insulating value for relatively little thickness makes rigid foam ideal for insulating roofs and exterior walls. Rigid insulation also substitutes well for other forms of insulation like fiberglass blankets and loose-fill cellulose in attics and floors. The water resistant nature of foam makes it well suited for use under slabs and in the ground around foundation walls.

Types of Foam Board
Rigid insulation is made of air-entrained plastic that is either extruded or pressed into sheets. There are three types of rigid foam insulation: expanded polystyrene (EPS), extruded polystyrene (XPS) and polyisocyanurate (polyiso), each varying in cost and R-value. Boards are available with a reflective foil facing that reduces radiant heat flow when installed next to an air space for total insulation against the three types of heat transfer, conduction, convection and radiation. If properly sealed, foil faced boards can also be used to form a vapor barrier in areas where moisture and condensation are an issue. Alternately, rigid foam can be installed in combination with reflective insulation to add a radiant or vapor barrier.

Insulation is rated by its ability to resist convective heat flow in units called R-value. R-value gives the insulation resistance per inch of material. Construction materials with higher R-value ratings are more effective insulators than materials with lower ratings for the same thickness. The R-value is a function of the material type, thickness and density. The R-value of an insulation system is calculated by adding the R-values of the individual components together to achieve the recommended insulation protection based on climate.

R-value is helpful in comparing different types of insulation as well as different brands of the same type of insulation. Rigid foam insulation has insulation values that are almost double the R-value per inch of fiberglass or cellulose insulation. R-values for rigid foam range from 3.6 – 8 per inch. Note that R-value is not used to rate a material`s ability to resist radiant heat.

Rigid Insulation Type R-value per inch
Expanded polystyrene board 3.6 to 4
Extruded polystyrene board 4.5 to 5
Polyisocyanurate board, unfaced 5.6 to 6.3
Polyisocyanurate board, foil-faced 7-8
(Source: US Department of Energy Insulation Fact Sheet)

State and federal agencies recommend insulation R-values for different areas inside of a building based on local climate conditions with the attic requiring the most insulation. Divide the recommended R-value by the R-value per inch of the type of insulation you want to use to determine the necessary insulation thickness. If you use reflective insulation in combination, you can add in up to an additional 14.5 R depending on whether the reflective insulation has foam, plastic bubbles or fiberglass for its central layer. Foam core reflective insulation (like foam board insulation) has the highest R-value. If you use foil faced rigid insulation facing an air space, you can add an additional R-value of 2.8 without increasing the insulation thickness.

Moisture Considerations
Preventing condensation in building cavities is a major consideration for an insulation system. Rigid foam board insulation resists absorption of moisture from the atmosphere in the form of humidity and also has a low water vapor transmission rate. However, rigid foam alone cannot be used as a vapor barrier. A vapor barrier should have a permeance rating of less than 1. The permeance of 1 inch of expanded polystyrene is 2 and the permeance of 1 inch of extruded polystyrene board is 1.2. In contrast, the permeance of aluminum foil is .001. Reflective insulation or foil facing is commonly used in combination with rigid insulation to create the vapor barrier necessary to keep moisture out of the walls and ceilings where it can cause rot, mold, mildew, odors, condensation and dripping. To create the vapor barrier, all seams are tightly sealed with aluminum tape.

Moisture also creates a heat transfer problem of decreasing efficiency when insulation gets wet as water is a good conductor of heat. Rigid foam board has been shown to retain its structural integrity through freeze-and-thaw cycles. It retains very little moisture in comparison with other types of insulation like fiberglass or cellulose. The Energy Division of the Minnesota Department of Public Service found that Expanded polystyrene used in exterior foundation insulation showed moisture levels of only 0.13% after 7 years of use. They concluded that the damp insulation board still maintained between 95 and 97 percent of its original thermal efficiency and compressive strength.

Benefits of using Rigid Foam Board Insulation

* Density – Density provides hi R-value with minimum thickness making rigid insulation more resistant to air and water vapor movement than fiberglass batts or cellulose.
* High compressive strength – rigid insulation provides a solid structure under the roof deck that can withstand the weight of both equipment and light foot traffic.
* Low weight makes rigid insulation boards easy to install and less expensive to ship.
* Resists outside air infiltration when joints are sealed with tape or caulk.
* New products are made without ozone depleting chemicals for virtually no global warming impact.
* Can be installed with full coverage over studs instead of just between them to eliminate the heat loss path through framing members.
* Non-hazardous to install – no fibers or fumes to inhale, non-irritating to skin.
* No deterioration of R-value over time – rigid insulation does not lose R-Value over its service life.
* Green – A manufacturing study showed that the energy required producing polystyrene foam insulation is 24 percent less than the energy required to make the equivalent R-value of fiberglass insulation.
* Rigid insulation “breathes” instead of trapping moisture like fiberglass or cellulose and therefore does not require the venting methods used for other insulation materials to prevent trapped moisture within walls, ceilings and roofs.
* Highly resistant to mold
* Not a food for insects
* Good acoustical insulation properties
* Can be used in structural insulated panels or for insulating concrete forms.

Expanded polystyrene (EPS) or beadboard, has been used as common household insulation since the 1950s. EPS is environmentally friendly as it is not manufactured using CFCs or HCFCs- both ozone-depleting chemicals. In addition to insulation, EPS is commonly used to make coffee cups and packing peanuts for shipping.

EPS is closed-cell foam made from polystyrene (a type of plastic) beads mixed with pentane and steam, used as a blowing agent, to expand the beads under pressure into foam, which forms thousands of tiny air pockets in the finished board. As air is a poor conductor of heat, these tiny air pockets will block the transfer of heat through the foam and trap expanding warm air.

EPS is molded into large sheets with R-values ranging from 3.8 to 4.4 per inch, depending on the density of the material. However, air spaces in EPS can accumulate and retain water. Because water is a good conductor of heat, some form of moisture barrier may be required to prevent this problem in high humidity areas, especially when EPS is used around foundations. To make the insulation more waterproof, EPS boards are available with optional thin foil or plastic facings.

Extruded polystyrene (XPS) or blueboard, is also a closed-cell foam insulation made from polystyrene plastic beads mixed with chemicals to turn them into a liquid before using a blowing agent to turn it into foam. The foam is forced through a shaping die, cooled and cut into panels.

XPS is more consistent in density and has a higher compressive strength than EPS making it better suited for use in roof assemblies and structural insulation panels. Higher density makes it more resistant to moisture than EPS, and XPS has a slightly higher R-value of R-5 per inch. Because of its superior properties, XPS is more expensive than EPS.

Polyisocyanurate or Polyiso, has the highest R-value per inch of thickness of the different rigid foam insulation types with an average R-value between 5.6 and 8 depending on the facing material. Facings such as plastic or aluminum foil increase its resistance to both moisture and radiant heat transfer. Polyiso is commonly used in roofs and cavity walls because of its thinness.

Polyiso is touted for being an economical choice. Its higher R-values per inch allow for savings on other building materials like thinner walls and roofs and their associated shorter fasteners.

According to the Polyisocyanurate Insulation Manufacturers Association, polyiso is a completely green building product as it no longer is made with either of the ozone depleting chemicals – CFC and HCFC. In addition, construction site waste can be recycled. Other beneficial characteristics of polyiso include its resistance to solvents in common construction adhesives and high fire test ratings.

Foil faced polyiso insulation has the highest R-value per inch of any type of mass insulation currently produced. When installed facing an air space of at least 1″, the R-value will increase by 2.89. ASHRAE assigns a 1″ air space R- 2.77. The Masonry Advisory Council adds an additional R-2.89 to polyiso insulation for a foil facing.

Rigid foam insulation boards used to insulate the interior of masonry walls do not require an additional vapor barrier. Wood strapping is attached to the wall and the insulation is installed over the strapping. If a foil-faced board or reflective insulation is used also, the foil side should face the room and an additional layer of wood strapping is needed under the drywall to create an air space. Fire safety codes require that at least ½-inch thick gypsum board (dry-wall) be placed over rigid foam insulation. The drywall is then attached to the wood strapping or underlying masonry with nails or screws. For insulating an unventilated crawlspace, rigid insulation boards can be glued directly to the wall.

Six Steps to a Greener Home

Here are six things anyone can do to their home to make it greener. A “green home” means a lot of things. But it always includes energy efficiency. These simple things increase the efficiency of the home by attacking the most dramatic energy loss aspects of a house.

They are relatively cheap and simple steps but their energy efficiency is actually very powerful. Doing these things can in most cases save you more money on utility bills than doing anything else.

1. Add a layer to your attic insulation,
especially if your home was built before 1980. This is one of the easiest and most effective ways to cut heating and cooling costs, according to the Department of Energy. As a general rule, if you have less than 12 inches of insulation in your attic, you probably need more.

2. Seal all cracks and crevices, both inside and outside your home’s building envelope.
Pay particular attention to penetrations for cable wires, plumbing pipes and electrical boxes, as well as those spots around windows and doors where siding or bricks and wood trim meet. Use expandable foam-sealant products around doors and windows, then finish off with the best-quality caulking you can find. Make sure all products are low in volatile organic compound (VOC) content to ensure good indoor air quality.

3. Seal the ducts.
More than likely, thanks to leaky ductwork, you’re heating your attic and basement and wasting energy. That’s because small cracks or holes in the ducts leak warm, conditioned air into the unheated spaces through which the ducts travel. So check your ducts for leaks, and use duct mastic (preferable) or duct tape (acceptable) to seal the leaky spots. If you’re installing ductwork in an addition or new home, consider installing the ducts in conditioned spaces, or make sure the ducts are well-insulated.

4. Install a programmable thermostat.
By programming your thermostat to lower your home’s air temperature when no one is home this winter (say, from 72 degrees to 65 degrees during the day), you can save as much as 10 percent on your heating costs. Programmable thermostats are priced from about $30, which you should be able to recoup in the first year of use.

5. Check and, if necessary, replace furnace filters,
and clean air registers, baseboard heaters and radiators as needed. By changing filters monthly, you can save as much as 10 percent on heating costs.

6. Insulate the water heater and pipes.

If you haven’t insulated your water heater, you may be losing heat into the surrounding area, which in turn will make the water heater work overtime to keep the water hot. Consult your water heater directions or a qualified water heater professional to determine whether your water heater is properly insulated. Also, insulate hot water pipes to keep the water in them warmer longer. Insulating materials for pipes and water heaters are available at hardware and home improvement stores.