Zero Energy Houses

One technology I have my eyes on is developed by Isomax.

They build homes that require basically no heating or cooling at all, regardless of where the house it. How do they do it?

They use a series of air and water tubes and ducts to pass heat and cold around. They have tubes in the roof and walls that pass either into the earth outside the house or into the earth beneath the house. The area outside the house cools the tubes and the area beneath the house heats the house. The same happens with the air ducts.

The area beneath the house becomes a heat storage area as hot water from the roof and walls during the summer passes under the house and leaves the heat. Then during the winter that very same heat is still there but only now it is taken out of the earth and put back into the house.

The house takes two or three years to really get going because you need one or two summers to get the ground under the house warmed up but after that you can expect a house that stays the same constant temperature throughout the whole year.

It is a very interesting technology.

Passiv Haus (Passive House)

A “new” construction style coming out of Germany creates houses that barely need energy to run. They don’t even have heating systems. In the dead of winter they might need a little space heater but that is is. What is the secret?

Insane amounts of insulation, triple pane windows, fanatic air sealing, smart solar design, good air circulation and efficient appliances.

Here is a list from their site:

Compact form and good insulation:
All components of the exterior shell of the house are insulated to achieve a U-factor that does not exceed 0.15 W/(m²K) (0.026 Btu/h/ft²/°F).

Southern orientation and shade considerations:
Passive use of solar energy is a significant factor in passive house design.

Energy-efficient window glazing and frames:
Windows (glazing and frames, combined) should have U-factors not exceeding 0.80 W/(m²K) (0.14 Btu/h/ft²/°F), with solar heat-gain coefficients around 50%.

Building envelope air-tightness:
Air leakage through unsealed joints must be less than 0.6 times the house volume per hour.

Passive preheating of fresh air:
Fresh air may be brought into the house through underground ducts that exchange heat with the soil. This preheats fresh air to a temperature above 5°C (41°F), even on cold winter days.

Highly efficient heat recovery from exhaust air using an air-to-air heat exchanger:
Most of the perceptible heat in the exhaust air is transferred to the incoming fresh air (heat recovery rate over 80%).

Hot water supply using regenerative energy sources:
Solar collectors or heat pumps provide energy for hot water.

Energy-saving household appliances:
Low energy refrigerators, stoves, freezers, lamps, washers, dryers, etc. are indispensable in a passive house.

Installing the concrete slab

We have a cellar half of the ceiling on the south side being open so that large amounts of light stream in and make a very nice living area.

First we dug out the cellar 3 1/2 feet:

While digging we found a giant stone which I decided to keep and put under the stairs, much to head shaking of everyone else. They wanted to dig a hole and bury it. I want to give it a name and designate it the protector of the house. I’m different that way I guess:

Then we underpinned the walls:

Then 3 inches of insulation including around the border.

Salvaged steel from fencing. From this:

To this:

Pex hot water tubing (the black foam is to insulate some water pipes in the ceiling):

4-5 inches of concrete. We used cement and sand without rocks to not damage the tubes.
We decided to not use Fly Ash in any of the cement because even though fly ash makes a better mix and is also recycling material I had doubts about the heavy metal content of fly ash.

Passing the concrete into the cellar along a chute we made out of plywood:

Coloring. We scattered a cement/sand/color mixture and troweled it in. I’m not sure I like the coloring. I wanted something warm and sunny for the cellar but it turned out a little too dramatic. I might sand it down a bit to remove some of the intensity. We might also cut grout lines and put some lighter grout to also cut down on the intensity.

Fanatic Insulation

I have a moto that I live by when building: Fanatic Insulation. I’m not sure if I coined the phrase but I think I did :). We use weather barrier, caulk, insulation, foam, flashing etc like there we’re building an antarctic deep sea submarine.

Considering some European standards, notably in Germany, our insulation style actually isn’t that fanatic. Just recently I was reading about homes in Germany that are so well insulated that in the dead of winter all they need is a little portable heater to heat the entire home. Or one small fireplace. Now that is energy smart!

A house needs to seen as a living entity and a renovation is an operation. When you sew them back up again it needs to be done with thoroughness and accuracy. You wouldn’t leave a patient with a gaping hole in them and the same applies to a house. It needs to be sealed correctly with the correct materials.

Otherwise “infection” will occur. In the form of wood rot from water, wasted energy from air, etc.

Now of course the houses in Germany aren’t just warm because of insulation. They are “passive houses” and of course passive heat from the sun helps.

And if a house is fanatically insulated then you have to give it “artificial lungs” since it is no longer breathing through the cracks in the walls. Fans, windows, air circulators and vents need to be added intelligently so that the house can breathe otherwise the very well insulated air stagnates in it’s own soup.

The key in this is to do it more effectively than the cracks in the wall that while letting the house breathe also let in the elements. A heat transfer plate is one cool tool where the heat going out the house heats the air coming into the house. Likewise you can have the same tool for the water; where the hot water going out of the house (shower, dishwasher etc) heats the water coming into the house through heat transfer coils.

Laying the foundation for the concrete slab

We have completely dug down the cellar by 3 and 1/2 feet. Then we put a vapour barrier and 3 inch insulation which we taped at the seams. Then we put down the salvaged fencing from the back yard to act as strengthener for the cement. On the fence we tied the pex tubing for the radiant head.

Meanwhile on the ceiling we are insulating the pipes. Fanatical insulation is the trick to green building.

The next step is to pour the cement.

Wood Flooring courtesy of Corcoran

Only in USA are dumpsters so full of wonderful stuff. And you can’t get fancier than a Corcoran dumpster. There is one in front of the Corcoran condos on President St in Carroll Gardens. I had the good luck to check them out today and found 1000 sq.ft. of once used wide plank maple flooring!

The builder was there and he said they were installed six months ago in the summer. Probably because they weren’t acclimatized correctly they warped a little. But my carpenter says it’s nothing the correct nails and some sanding can’t fix.

So it looks like the green show house will have 100% salvaged flooring. We salvaged some oak from another reno a couple months ago.

The Costs of Recycling

Above Pic: “ugly” wood that I use for everything from studs to window frames.

Recycling is a great way to reuse materials and save money. It is important to keep in mind the extra costs of recycling.

If you get the materials for free, say from a salvage, that is a great starting point. It beats paying for it from a store.

But free or not you then have to have a use for it otherwise you need to pay to store it until the job is ready. This costs money.

Secondly, and this is often an issue with wood or metal studs, recycled material isn’t always clean. My carpenters have never felled a tree for wood. They are used to reaching their arm out and grabbing a perfectly cut clean piece of wood that fits exactly what they need. This is the consumer society we live in.

And I am always getting grief from my carpenters about this. I bring them ugly, nail ridden, odd sized wood and ask them to work with it. They don’t like it. It takes them precious time to clean the wood and size it for their needs.

In fact today one carpenter said he felt guilty because he was wasting so much of my time (=money) using the old wood instead of out of the box new wood.

But the important thing to understand is that it is still better. I would rather pay my carpenter the money instead of the store. Despite the obvious benefits of recycling etc, I’m still saving money.

I may pay the carpenter $20 extra but I save $15 because I didn’t pay for the wood. Even if I wasn’t saving any money at all I would still do it.

It makes too much sense not to do it. It means my carpenters need to slow down. It means my studs won’t be nice and clean looking. But it also means I’ve saved some trees, the wood is stronger than the crap they speed grow today, I’m lessened the landfill burden, and I might even save some money!

Soundproofing between floors

After some research we noticed that one of the most effective ways to reduce impact noise between floors was to put a recycled tyre product between the floor and sub floor. It creates a vibrating cushion that absorbs the impact, thus deadening the sound.

The only problem is that this product is costly. And costly is not green in the slightest.

So we went to the mechanic down the road. He was more than happy to give us some used tires. He has to pay to dispose of them into the landfill. We took the tires and cut them into little strips.

The strips were placed wherever a stud or support beam made contact with the floor above, creating a sound impact barrier between the two floors. Kids jumping, heavy boots and games of basketball should all become less audible from the neighbors above thanks to our technique.

Cutting the tires into strips.

Placing the tire under the joists.

The same tire pictured above but now we have put the support beam beneath it. The tire now acts as a sound barrier between the joists and the beam, breaking the vibration that would normally pass from the joist to the beam and the floor below.

Here is an example of the tire placed between the stud and the footer. It is better to place the tire between the stud and the header to stop sound coming from above. But in this case the stud was supporting the stairs so it didn’t matter.

Fiberglass Windows

I paid a lot of money for fiberglass windows for the Brooklyn Green Show House.

Despite the cost, the fiberglass frame part I LOVE. I think this is the way to go. I really love them and once they are nicely painted and repaired I will be very happy with them. When it is cold outside you touch the frame and it is almost warm, meaning it is not letting much of the cold in or heat out.

The above photo shows us installing the windows. On the right you can see one installed.

Unfortunately fiberglass windows are expensive. And there are no local fiberglass window manufacturers in Brooklyn. As a Brooklyn green contractor local materials is important to me.

For the past two jobs we have actually suggested the client go with locally made vinyl windows. They are very affordable, locally made and as of late I have disliked vinyl less.

Lowering the Cellar Three Feet

In order to maximize the living space we decided to turn the cellar into a useable space. To do this we cut a 10×10 foot hole into the floor of the basement, which is only technically called the basement since it is a foot below grade. Practically it is the garden level. Once a hole was in the south side of the garden level it allowed plenty of sunshine to pass into the cellar.

The only problem is that the cellar was only six foot high. So we have dug it out another three feet. We had to dig under the existing foundation, which can be risky if not done correctly. First we built a second inner wall out of cinder blocks in the entire cellar. The existing brick wall was so deteriorated you could pull the bricks out by hand and it was actually amazing the four floors above kept standing.

The cinder block wall only took up four inches but added all the strength we needed to support the house, which we were in the process of banging and shaking to no end. We then dug down three feet in small areas at a time and underpinned the wall with concrete and the rocks we found in the soil.

Before putting the concrete we put plastic vapor barrier and two inches of waterproof insulation to guarantee a warm and dry environment.

Above you see the sections being dug out.

Above is the vapor barrier, called Stego wrap. It is one of the few plastics that actually do stop moisture and is priced accordingly. Most cheaper brands don’t actually stop moisture.

Here we are putting the plastic, insulation and making the form to pour the concrete and stones.

We used XEPS or extruded polystyrene, which is a dense and waterproof insulation. It is also not friendly to termites, which is important in this area.

Here you can see the rogh finished product where the floor had been dug out and the underpinning poured. We will then pour the concrete floor and then build the cinder blocks up to the other cinder block wall that is currently hanging three feet above ground.

Here you can see the opening in the floor above. We have also knocked out the south wall for a wall of windows so the sun can really shine down into the space. On the front and back walls we did not put cinder blocks because those walls had good solid stone as you can see in the picture. You can see the concrete underpinning under the stone walls where we dug down. A worker is finishing off some underpinning but using cinder blocks instead of concrete since that little alcove is not holding up the building and does not to be as strong.

This photo shows the cellar before dug down. As you can see there was little headroom.

Here you see the same cellar almost all dug out.

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.

About House Wrap and Tar Paper

Here is an interesting article. It describes all the kinds of house wraps and vapor barriers in detail. It also concludes that despite all the fancy new products the good old tar paper is still the preferred product for the author.

I like building that sticks to the basics and avoids as much as possible fancy high tech products. If it can be manufactured simply without lots of machinery then it is more ecological. Of course tar paper has tar, ie oil, but all the other wraps are also petro chemical based too….

So for our green project on 2nd street we are going with tar paper for the vapor barrier between the bricks and insulation. Then between the insulation and the inside sheet rock we will use a radiant barrier for more sealing and to radiate the heat back into the house.

The file is here.housewrap-tar-paper

Hemp – Stonger and Lighter than Cement

I subscribe to some very scholarly journals on green building. I also subscribe to some radical journals on politics and conspiracies. I like to check out the pulse from various sources. And when I start seeing trends overlapping I know it is something worth paying attention to.

This week I was reading in this one very academic journal about the use of hemp fibers mixed with lime to make a concrete-like material that is stronger and apparently six times lighter than real concrete. It is used in France a lot and expanding around Europe.

And then one of my conspiracy journals also spoke about it, but from the perspective of it being this miracle material that was being kept from the building industry due to political reasons (hemp apparently has many uses that threatens existing companies, namely oil and timber companies).

Seeing it in two widely different contects raised my interest. It does indeed seem to be a viable building material on the rise. Worth keeping an eye out for it.

The basics:
hemp grows as a plant, thus CONSUMES CO2.
it grows abundantly and quickly, thus is rapidly renewable.
because it grows, it does most of the production itself reducing embodied energy.
once it is made into “concrete” the CO2 is fixed into the walls, thus it is a CO2 neutral or possibly even CO2 NEGATIVE product.

portland cement requires huge manufacturing power and thus creates massive amounts of CO2. It is the largest creator of CO2 in the building industry. Enough said.

Basically, the connection of hemp with weed smoking hippies is a farce. Hemp has too many positive attributes, from paper, oil, wax, cement (the list is long) for it to be considered negatively.


What We Need, the Basics

There are certain inalienable elements that every human needs in their environment in order to stay healthy and happy. These elements are green, timeless, and universal.

They are:

1. sunlight by day
2. darkness by night
3. greenery
4. water
5. meaningful sounds
6. fresh gently moving air
7. thermal comfort within thermal variation (not too hot or cold but some variety)
8. interaction with other humans and other species
9. a sense of safety
10. dynamic synergy among all of the above things

Any design process, whether it is moving furniture around or building a new house, should take these ten points into consideration. To do so will guide you down a path of health and happiness.

Note: the ten points are from Carol Venolia, eco-architect.

Green Home Building – what is it?

“Green” is one of those words that are tossed around all over the place. Here are some concrete green things for a home renovation:

1. Find a contractor who uses efficient framing techniques to save on wood while still keeping the structure strong.

2. Find a salvage yard that buys and sells reusable materials, then buy and sell with them as you do your renovation. Sell them the stuff you take out and buy from them the stuff you put back in.

3. Install energy efficient windows (go triple pane if you can), doors, and appliances.

4. Build with solar gain in mind: get more sun in the winter and less sun in the summer by using trees (bare in the winter and leafy in the summer) and awnings; Use more windows to the south and less on the north.

5. Use smart technology in the materials: Optimum Value Engineering techniques to reduce the amount of wood and other materials, low VOC’s in paints, cabinets, etc, non-formaldehyde in the materials and so on….

6. Economize: buy local, buy less, build only as much as you need. Stay wholesome and don’t try to keep up with the Joneses: build what you need practically, not what you think will impress people.