DIY Rocket Mass Heater

The recent polar vortex has hit us all with some really harsh conditions and as a green contractor based in New York it has made work on our ecological construction sites difficult. Spending cold, winter days inside of an upcycled shipping container can leave you freezing for hours. Space heaters require electricity that you may not have access to.

We’ve figured out a way to heat our workspaces in an environmentally friendly and sustainable way that uses zero electricity and burns zero fossil fuels.  A rocket mass heater is an efficient wood burning stove and space-heating system. Two key things differentiate them as ecologically sound space heaters.

The first is that the design involved creates a small, efficient, high temperature combustion chamber capable of burning significantly more carbon than simply burning wood in a metal can or bonfire. Due to the high carbon-burning capabilities less ash is created and the smoke emitted is much cleaner.

The second is that the cob or clay acts as a thermal mass that physically stores the heat created during combustion for hours and releases it into the space through convection thereby decreasing the amount of electrical energy or fossil fuels used.

A traditional rocket mass heater involves a 55 Gallon drum built into a clay wall and extending into a room so as to transfer the most heat possible. This form is too large and too permanent for use on multiple construction sites.  The technical design of a larger scale heater is more complex, but we needed a relatively small heater that can be transported between sites.

The method of building a rocket mass heater outlined below enables environmentally conscious contractors and individuals to use materials that are more readily available or perhaps lying around the house or job site.

Here we’ve provided the simple DIY steps to creating a rocket stove or rocket mass heater:


5-gallon plastic bucket

2 2-liter plastic soda bottles

Dirt, grass (or hay), and water


Duct tape

Utility knife

A piece of metal lath or mesh


Step 1: Use the marker to trace a circle 3-4 inches from the bottom of the 5-gallon bucket and cut out the circle with your knife.

Step 2: Use the duct tape to tape the ends of the soda bottles together in an L shape. The soda bottles should be filled with liquid or remain unopened.

Step 3: Use the dirt, grass (or hay), and water to make the cob in a different bucket.

Step 4: Put some of the cob in the bottom of the bucket to the height of the bottom of the hole you’ve cut. Place the bottles you’ve taped together inside the bucket with the end of one bottle sticking out of the hole that you’ve previously cut.

Step 5: Continue to fill the bucket with the cob mixture and be sure to smooth all edges. The clay will need a few days to dry out.

Step 6: When the cob feels dry pour the liquid out of the soda bottles and cut off the tops of the bottles. Remove the bottles and tape by reaching into the bottles and pulling them out.

Step 7: If your cob mixture is not fully dry let it set for a few more days. Then place paper and small twigs inside and light a small fire to dry the cob entirely.

Step 8: Place the piece of metal lath or mesh, small enough to fit inside of the hole, in the side of the bucket. This will hold the fuel being used to heat your space. It should be long enough that it sticks out of the bucket to hold longer sticks/kindling.

Step 9: Add your fuel (paper, sticks, any natural carbon-based material will do) and ignite!

This rocket mass heater is safe, environmentally friendly, and portable. For use indoors this structure would need to be ducted to allow exhaust or fumes to be safely expelled outside. Additionally, use of this type of heater in a home remodel is not recommended however for work on an industrial space it is a perfect fit.

Click HERE for a link to a smaller, even more portable version.  We don’t recommend this exact method due to the high levels of BPA inside of soup cans so we suggest purchasing heater duct pipe (un-galvanized) to use instead.


Click HERE to see different designs for large scale and conventional rocket mass heater. These designs are meant to heat a home and emit smoke  and any potentially dangerous fumes outdoors through a duct system.



Building for Children

Eco Brooklyn recently completed a number of jobs in a building where there were children living. We renovated  three children’s bedrooms, two bathrooms where they bathe, and two play areas. Doing this increased our focus on using non-toxic materials and building in a manner that created no dust.

A toxin free green building process should be done in all homes, but because children’s bodies  are so much more absorptive of chemicals than adults, the harmful effect on children can be much greater if precautions are not taken.

Eco Brooklyn has a zero toxin policy in our home renovations. But that is a lot harder to accomplish than people think and we don’t always meet our goals.

The reason is that even the most harmless building material has toxins. Take sheet rock compound for example,  used to plaster the seams of sheet rock. With the exception of a very few buildings (adobe, for example), sheet rock compound is in every single building in america.

Sheet rock compound contains Formaldehyde, a known cancer causing chemical. To the trained nose, Formaldehyde is easily detected in a newly built home. True, it off-gasses very quickly and although I don’t have numbers to back it up, I feel that the Formaldehyde levels in dry compound are very small.

But what if you are building in an apartment where children are currently living, like we recently did. The apartment had a six week old baby and we were posed with the challenge of repairing some sheet rock. The family was not able to move during the renovation. This is not an ideal situation.

Our solution was to seal off the area with taped plastic walls and to make sure we had a window in the plastic enclosure.

We then created a negative vacuum in the work area by blowing a fan out the window. That way air was constantly being sucked into the enclosure and out the window. Due to this constant pressure minimal dust or toxins entered the rest of the apartment.

Likewise the workers took great pains to clean themselves before leaving the enclosure. We left the enclosure up for two days while the bulk of the Formaldehyde off-gassed out the window.

We then painted with zero voc paint, which again for a green builder like us is pushing the boundary of what we consider safe. Even though the paint may be zero voc, if it is a mainstream company (Benjamin Moore, for example) then the paint contains hundreds of chemicals, most of which have only been around for a couple generations.

Like the millions of chemicals humans have created over the past several decades, we don’t really know the long term effects of there high tech paints. You just have to smell a zero voc mainstream paint to know it isn’t harmless. It smells like toxins.

It would be great for our health if we all lived in adobe buildings, surrounded by natural materials like wood, earth and stones. I am convinced cancer rates would plummet  But most houses are not adobe. As New York green contractors our strategy is to educate ourselves as much as possible in non-toxic hypoallergenic building techniques and apply those strategies to existing conditions, which often are not ideal.

When possible we eliminate the toxins. We never use wood with Formaldehyde (often found in cabinets, flooring, counters…). All our floor finishes are natural oil based. We build a lot of clay walls. We have built a lot with non-Formaldehyde sheet rock compound, although it is more expensive and not as easy to work with.

When it is not possible we do our best to understand the risks and to reduce exposure as much as possible. Simple plastic (yuk!) walls and negative pressure techniques do wonders to reduce any dust or toxins in the living space. An educated work force takes care of the other exposure issues (simple things like removing shoes, blowing off our clothes, washing our hands….).

After considering the immediate effects of toxins like airborne gasses and dust on adults and children, we as a green building company are interested in finding and understanding environmental stressors that may contribute to more subtle and long term childhood issues like OCD, ADD and Autism.

This is part of our Build It Forward process where we are not only thinking of the current client but are also considering future generations. That is our gift that we build forward into the renovation. Likewise the client is paying a little extra to benefit people they many never even meet. This process is very different to the slash and burn building technique that dominates the industry and has caused so much harm to our world.

That extra up front building cost that we as a green building company and the client share is pennies on the dollar compared to the massive hidden costs we all end up paying later when we build with no consideration for anything but maximum up front profit.

It is the difference between paying cash for something that you then pass on for free to your children vs. paying with a credit card that has outlandish interest and that you give to your children as a death present.

With this attitude it is easy to understand our obsession with uncovering hidden costs (financial, social and ethical) and paying for them up front. If you want to be perfectly callous, you could say this for us is simply smart long term business planning. aka it is sustainable in the long run.

As we research what is smart and not smart building we never forget the myriad of  political, economic and social interests behind many of these chemicals it is hard to know the truth. For example, for decades “studies” came out saying there is no connection between cancer and tobacco…

So most of the time when we are building we have nothing but common sense to back up a lot of what we do. And we use historical reference. This means we not only look towards the newest science for guidance but we also look into the history of building in different cultures. The Eco Brooklyn office has a whole wall of books on traditional building techniques and cutting edge science techniques.

So when we build, if it makes sense to do something and we have evidence that a certain society utilized the same technique with success then for lack of any other authority we will use our best judgement to decide.

For example, historically clay walls have been used safely since the beginning of time in construction. Recently there is also mounting evidence that the negative ions in clay cause people to feel good. These are the same negative ions found after a rain storm when the air is fresh and the light is crisp.

At the same time there is evidence that one of the ingredients in clay walls contributes to cancer – silica. It is added either pure or in it’s most common form – sand. Of course people have worked with sand since the beginning of time as well.

As builders we look at all this information, determine the benefits and risks and then decide how or whether to use the green building technique. In the case of clay walls we feel that there benefits are great. The ongoing exposure to silica from the wall dusting is minor and we feel does not contribute as an environmental stressor that may contribute in aggregate to cancer.

So in the case of clay we wholeheartedly use it. Other applications, such as zero voc paint or sheet rock compound, we use but with less enthusiasm and with a lot more care in order to reduce the risk to an acceptable level.

We understand we can’t eliminate all environmental stressors. Sunshine after all can become an environmental stressor that when combined with other elements (genetics, formaldahyde etc) can contribute to cancer. But we feel the benefits of sunshine far outweigh the risks and we enthusiastically encourage windows in buildings :).

The point here is that as New York green contractors we feel our role is more than to build kitchens for people. We need to educate ourselves not only in how to professionally install kitchen cabinets so they look great and work perfectly but also we need to understand our role is one of amateur doctor, educator and social activist.

Along with the normal questions like, what color are the cabinet doors, how do the hinges work and what handles does the client want, we try to ask ourselves other questions as well, questions that definitely will impact the client much more in the long run.

These questions are different for each situation but they always focus on the triple bottom line of planet, people and profit. What is the health impact on the client and the environment (is the wood free of chemicals and salvaged)? Who wins and who loses financially (are workers paid fairly)?

The questions are endless and the answers many. It is more an ongoing process than a final goal. As long as we keep at it I feel we will continue to be effective New York green contractors.

This blog was inspired by a recent article I read about chemicals and autism. Here are a list of chemicals you can be pretty sure contribute to autism (and cancer, headaches, mood swings, tiredness and just simply a shitty day). If you have time you can google the chemicals to see what products contain them.

If you don’t have time, then use your common sense. A popcorn bag made out of some sort of plastic that you put in a microwave? Duh! Save yourself some time and go smoke a cigarette instead. Not sure if a liquid is toxic? What does it smell like – a new car or a walk in the forest – hint: that new car smell gives rats tumors the size of grapefruit.

Really a better term for this than common sense is being aware of your surroundings. Most people are aware enough to notice a fire in their house. But how many are aware of the smell in their new pillow and whether it will give them cancer in 20 years? Studies show it very well might (although there are plenty of others that show it won’t….but again it is worth looking at who is pushing what study….).

The first step in becoming aware is to pay more attention to your body and to use available information both current and historic to see what works. Available info and history show that certain activities and foods work while others don’t. You don’t need to be a genius to know the basics of exercise and died to live a good life.

And yes, exercise is a great way to reduce the harm of that new paint since an increased metabolism passes the toxins our of your body faster.

Here is the list for chemicals connected to autism..

Found in paint, dust, drinking water, some canned imported food, older toys, some imported toys, lead-glazed or lead-painted pottery, and some inks.

Methylmercury is not the same as ethylmercury, the form found in Thimerosal, the controversial preservative formerly used in vaccines and which some believe is linked to autism. Methylmercury is released into air and water mostly from industrial emissions. It is the form of mercury that is found in high concentrations in some fish.

The U.S. government banned production of PCBs in 1977, but they continue to be released into the environment from hazardous waste sites and from illegal or improper dumping. PCBs are also found in some types of caulk used in building materials, including in some schools.

Organophosphate Pesticides
These make up the majority of pesticides used on fruits and vegetables ingested by pregnant women and kids in the United States.

Organochlorine Pesticides
Less common, organochlorines are still used. The most infamous organochlorine is DDT, which was fully banned in the United States in 1972.

Endocrine Disruptors
Endocrine disruptors are chemicals that can potentially interfere with prenatal development. There are literally hundreds of endocrine disruptors, the most well-known of which is bisphenol-A, or BPA.

Automotive Exhaust 
Toxins of concern in motor vehicle exhaust include carbon monoxide, nitrogen dioxide, and sulphur dioxide.
Polycyclic aromatic hydrocarbons
These chemicals are found in an array of sources — from cigarette smoke and burning coal to industrial waste incineration and hazardous waste sites.

Brominated Flame Retardants
These fireproofing chemicals are added to pillows, vehicle seats, fabrics, and some electronics — including computers.

Perfluorinated Compounds
PFCs are found in sources as varied as water-resistant clothing, some non-stick cookware, and microwave popcorn bags.

Eco Ponds in NYC

We have been experimenting a lot with self sustaining garden ponds lately. One thing is to build a pond that looks like a black bathtub with half dead plants and a goldfish, another thing is to create a diverse ecosystem that thrives.

The trick is to design it right. And they will come.

The bugs, plants, birds and bees will all migrate to the site naturally if you create the correct back bone for them to build their homes.

The industry standard is to build with PVC or EPDM linning. The first one is PVC and all the nastiness that entails. The second one is like a rubber inner-tube. Less toxic but still not natural.

We are looking into using clay as the liner, or more technically Sodium Bentonite. After all, that is what most naturally occurring ponds are lined with.

This pond in Turkey was made using a clay liner.

Clay is a wonderful material and in our NY green contractor work Eco Brooklyn loves applying it to walls. Almost all our jobs have clay, usually on the exposed brick party walls of the brownstones. We apply it like plaster in a myriad of ways depending on the look we want. Amazing stuff.

This morning I spoke with Joe Carmo, the local distributor of a product called Bentomat, an industrial version of clay for lining ponds. They have a great product where the clay is sandwiched between two liners, making it easy to apply. The cost is about $1/sq.ft before shipping.

The only problem is their minimum order is over 2,000 square feet and that weighs 3,000 lbs.

So yes, they supply liner for big ponds. For example here is one in China under construction with the product:

Pond Installation

The finished “pond” will look like this:

Little New York City green builders like Eco Brooklyn on the other hand want to build water features like this:

Michelle shows off her natural waterfal

In this pond we wanted to recreate something that would be natural to New York landscape (pre-NYC)

By installing a natural pond in New York city gardens you create ecological diversity where there previously was little. With our focus is on converting New York city front and back yards into little ecosystems in a sense we help reverse them to what they may have been several hundred years ago.

And clay lining is a big part of this plan. We’ll shoot out a blog when we find a way to source smaller quantities of this more ecological lining. It may mean buying Sodium Bentonite and figuring out a way to adhere it to a mesh….but we are still exploring.

We will keep you posted. It promises to be exciting! At least for us.

Two Rammed Earth Walls

Part of being a green contractor means studying emerging technologies offering more eco-benefits than conventional construction.  In this case we’re looking at old technologies: the rammed earth wall, one of humanity’s oldest building techniques.

When it comes to walls, a couple of rammed-earth techniques are available as alternatives to your standard insulation-filled 2×4 frames:

The Earthship model uses old tires as receptacles for rammed earth, and then uses them as building blocks for durable, energy-efficient walls.  They use waste and locally available raw materials, so the largest investment is labor.

New company Earthco Megablock has developed an automated mechanical system to generate compressed earth blocks.  Their materials leave a minimal carbon footprint (but still more than using manpower and recycled tires) and require less manpower to get the job done.

To clarify, I’m only talking about walls here: Both companies use rammed earth to make walls, but Earthco Megablock uses their technology to build “normal” 4-walls-door-and-windows houses while Earthship encompasses a whole sustainable lifestyle.  You could, for example, build an Earthship using Earthco’s blocks.

Earthship saves money by relying on networks of volunteers, while Earthco  reduces labor costs and building time by streamlining and automating the construction process.  Earthship is good for when you have time and people, but no money.  Earthco doesn’t require time or people, but you do need money…and somewhere to put their machine.

So if you’re building in, say, Haiti, you’d go with Earthship because it’s easier to truck in volunteers or laborers instead of shipping in a huge honking machine from the U.S…and that’s exactly what happened in the latest Earthship project, which you can see on their website.  Meanwhile, in America, there might well be a market for the professional service Earthco has put together.

One of Earthco’s goals is to change green construction from an idealistic collaboration into a commercial presence.  To quote from their web site: “While some people are not yet convinced about the need for “green” construction, everyone is into superior quality and saving money.”  They have a point: the best way to make green building methods mainstream is to  beat the mainstream in price and quality.

The trick is to do this without incurring the hidden costs that typical construction has (one example, the cost of new 2×4 lumber is so cheap because nobody is paying up front for the environmental costs of clear cutting a forest).

We’ve discussed Earthship before, but Earthco is a new find, so here’s a quick summary of their method, followed by some pros and cons:

Giant Compressed Earth Blocks are made by transporting proprietary machinery to your location, where local dirt is squeezed into compressed earth building blocks that are immediately built into walls.


Production is sustainable and affordable.  Using local materials and manufacturing on site means almost no carbon footprint.  Mechanized placement means less labor.  In general, walls can be built at twice the speed and half the cost of conventional lumber construction.

The walls are thick and offer thermal mass that retains heat while blocking wind.  Simply replacing lumber/insulation walls with block walls nets you 50% in energy savings.  Building to passive house standards (ensuring airtightness) boosts savings to 90%.  (But you can achieve similar results with conventional materials, which we’ve done.)

The blocks are virtually indestructible.  They’re built to withstand F5 tornadoes, wildfire, and gunfire.  In impact testing, a relatively shoddy block wall took a brick traveling at something like 1000 miles an hour.  The bullet, of course, disintegrated.  The wall hardly took a dent.


Simple earth block walls are not suited for areas with high humidity levels, as the blocks are water-resistant but not waterproof.  They need to be enveloped in some kind of waterproof outer layer, such as insulation, adobe, or stucco.

You can’t run electricity or plumbing through block walls.  You’d have to cut grooves to accommodate wires or pipes, or run them in through the ceiling or floor.

Personally, we wouldn’t be able to make use of this technology because we couldn’t get the machines into a Brooklyn backyard, and we’d run out of local dirt fast.  Trucking in the dirt or the blocks would defeat the purpose to some extent.  Tire-based rammed earth walls, on the other hand, are feasible because we could work at a smaller scale.


Eco Brooklyn has a rammed-earth wall in the cellar of our green show house.  What we did was more like this, because we have people in New York, but we don’t have space, so giant compressed earth block technology wouldn’t be a feasible choice for what we do.  We do a lot of retrofits on existing New York brownstones.  There isn’t a lot of room for rammed earth construction in our neighborhood, though rammed earth walls can be an aesthetic option.

That said, the most practical green construction method is always the one that makes the most efficient use of resources available to the builder.  Other than their use of rammed earth, Earthship and Earthco’s earth block technology are very different  innovative green building techniques with the potential to bring green building to different markets.

Eco Brooklyn is a big fan of the Earthship building technique and lifestyle.  The Earthco find is a nice addition to our resource list, and a company to keep an eye on.

Thank You Jesus

Here’s to every immigrant worker in the world. Did you ever think that countries were created to create cheap immigrant workers?

Here at Eco Brooklyn we love immigrant workers. Not because they are cheap labor. Eco Brooklyn pays based on talent alone, not nationality, race or sex. And if you have a family to support we might even pay more, regardless of whether that family is in Brooklyn or Guatemala.

We welcome people who come to America and send their profits elsewhere. Heck, America has been doing that to other countries for ages. We are happy to balance the playing field however small the contribution.

For us immigrants bring great traditional green building skills to New York. and we eat that shit up.

Clay walls, earthen floors, brick work, stone work, wood work and countless other skills are all old world techniques that people have been doing for thousands of years.  These are valuable skills to a green contractor in New York. These techniques are sustainable earth based skills not dependent on high embodied energy but rather on base elements like earth, clay, stone and water.

Here’s to you Jesus!

Clay Wall Application

As a New York contractor we are constantly trying to incorporate the best green building techniques to New York and Brooklyn brownstones. The creative use of clay is one of our tools. We just did a another clay wall job in Brooklyn.

We switched the mix up a little to make it a little smoother, less mold receptive and possibly healthier.

Our mix was:
calcium carbonate
white sand
saw dust
wood glue

We omitted two key things: silica dust and wheat paste.

The wood glue replaces the wheat paste. We did this because we found the organic nature of the wheat paste lent itself to mold. The slightest amount of water and you have a wonderful colony of mold growing up the wall.

We took out the silica because of concerns over the possible health issues. Silica is naturally found in sand but pure silica increases the amount drastically. Our concern is that the very slight dusting off the walls could cause unknown health issues years down the road for the tenants.

This may be completely unnecessary and unfounded, and in fact most clay wall mixes suggest silica, but we found we could make a good mix without it so why not? Silicosis is not a pleasant illness.

Other mixes we have had success with are:

white sand
marble dust
fine sand
linseed oil
wheat paste

This one gives a very smooth white finish that you can trowel down so it looks almost like Venetian plaster but still has the benefits of clay. Unlike clay, Venetian plaster goes through a chemical process and is inert. Clay does not and stays “alive” as it interacts with the humidity of the room.

Another mix we use:
calcium carbonate
marble dust
saw dust

The calcium carbonate makes the mix even smoother. You then add saw dust to give a contrasting texture and to add strength to the mix. Typically straw is used but we use what is local and we have lots of saw dust!

There is no right way of doing it as long as it lasts. We sometimes add milk paint either as a binder or for color. White milk paint really lightens up the mix. Milk paint comes in all sorts of great colors that really make the clay pop.

In the most recent mix mentioned at the beginning of the post we applied the clay over a scratch coat of cement that we applied to add strength to the load baring wall. If the wall is brick and you don’t need extra strength you can add it thick over the brick. This is great because you really get a lot of clay in the room. In this case the scratch coat was smooth so we added a thinner layer.

We didn’t add any color so it is the natural beige of the clay. Clay comes in a range of tones from white/gray to dark brown. We tend to go with a light sand color:


We chose to create a smooth surface and troweled the clay once it had dried a bit:



Another experiment we did that worked great was pointing of a brick wall. The interior wall was in need of clean up but we wanted to keep it exposed.  So instead of pointing it with mortar we used clay. Clay offers no structural strength to the wall but the the brick was in good enough shape that it didn’t matter.

By pointing with clay we had the advantage of using clay, which has humidity control and possibly even emotional benefits to the inhabitants, and we were still able to leave the bricks exposed.

Here we are pointing the brick wall with clay:


We’ll probably not seal the brick wall, instead we’ll just leave it bare to maximize it’s humidity control function. If you seal a clay wall you reduce it’s benefits drastically.



Clay Concrete Base Molding on Clay Wall

Eco Brooklyn is a New York clay wall installer. We don’t use any brand name clay mixed but prefer to mix the clay ourselves depending on the use. We recently installed some cool clay concrete base molding onto a clay wall. The challenge was that the clay wall was not flat enough for salvaged wood base molding. There would have been gaps between the wood and the clay wall. The other challenge was even if the wall was straight how do you attach the wood to the clay wall (on top of a brick wall).

So we decided to make a base molding out of a clay and concrete mix. It was a classic green building moment where practicality, aesthetics and green thinking synthesized.

The aesthetics of the clay concrete base molding went beautifully with the clay wall. And the clay base molding matched perfectly the wood molding in the rest of the house.


So how did we do it? First we made a plaster mold from the wood base molding. We put oil on the wood so the plaster wouldn’t stick:


Then we smeared the plaster onto the base molding. Once solid we had a mold of the wood shape:


With the mold as our trowel we pressed the clay and concrete mix onto the clay wall:


Once done it looked like a rustic but very real base molding that mirrored the texture of the clay wall and also mirrored perfectly the wood molding it butted up against (see in the pic below):


The end result was a harmonious use of design for the space. It worked well with the salvaged wood floor:


Clay Plaster Walls For New York Passive House

We are building a Passive House in a Manhattan brownstone. Instead of using more synthetic materials to air seal the brick walls (crucial for PH) we are using clay.

Here are some notes to a successful clay application over New York brownstone brick walls:

– Use reinforcment mesh (fiberglass is best, hemp is  mesh also usable, easy to work with if soaked in starch – more ridgid) wherever you have different materials that meet. On a flat brick wall, that is not moving, no mesh is necessary. but better save than sorry?! so use mesh anyways
– With clay, always make experimental surfaces and wait until dry (you can dry it with a heater, not necessary to wait for natural drying) Some surfaces (concrete, OSB) need a clay slick before applying regular clay plaster. The rule is more clay for the first layer, less clay for the next, least clay for the last. Never the other way round. Using mesh, maybe we can suffice with 2 layers? Let’s think about that.
– The first layer might crack, but that is normal and makes the second layer stick better. The last layer should be done in the same thickness and rather thin (3-4mm) over the whole surface, to prevent cracking
– You will get cracks between the plaster and for example wooden elements (ceiling or whatever). These cracks can be filled in later (just make them wet and add some clay), but any movement later will cause a minor hairline crack. If you have some hemp textile soaked in clay slick, press it to the wood with a small baton, then plaster over the whole. The soaked hemp is air tight, and any crack does not matter. Instead of clamping the clay hemp textile with wood the joist (cumbersome), we can drape the soaked cloth around the joist and then tape the edge of wood/hemp with 3m tape around the joist.

– Use reinforcment mesh in areas where possible settling or movement will occur. Fiberglass is great but has high embodied energy. Hemp works well too.  If you soak it in starch it is easy to work with and dries harder.  Wherever you have different materials that meet you especially need to put mesh. On a flat brick wall where you don’t anticipate moving no mesh is necessary.

– With clay always make experimental surfaces and wait until dry (you can dry it with a heater, not necessary to wait for natural drying) Some surfaces (concrete, OSB) need a clay slick before applying regular clay plaster.

– The rule is more clay for the first layer, less clay for the next, least clay for the last. Never the other way round. If you are ok with a rougher look or you are really good you can get away with two layers. We have even gotten away with just one!

– The first layer might crack, but that is normal and makes the second layer stick better. The last layer should be done in the same thickness and rather thin (1/16″) over the whole surface to prevent cracking.

– You will get cracks between the plaster and for example wooden elements (ceiling or whatever). These cracks can be filled in later (just make them wet and add some clay), but any movement later will cause a minor hairline crack. If you have some hemp textile soaked in clay slick, press it to the wood with a small baton, then plaster over the whole thing. The soaked hemp is air tight, and any crack does not matter.

Tribute To John Lennon – This Earth Floor’s For You!

What does green building in New York and John Lennon have in common? There must be something in common since as a NY green builder I get inspiration from him. And I know I’m not the only one…

In honor of his 70th birthday lets look at the commonalities.

There are many good builders just like there are many good singers but not all of them use their talents as a tool for a broader world goal. Just like Lennon and his voice, green building uses the tool of building to make an impact on the world.

Take a passion for humanity, mix it with musical talent and you get John Lennon.

Same goes for green builders. We love building and we love humanity too. Both make up the whole.

When John shared his opinions on humanity people listened because he was a great and inspirational singer.  The same goes for green builders. No green builder will have an impact unless they are also great traditional builders.

Green building is hero’s work. The moment Lennon took his talent and applied it to something larger than himself he became an icon.

We can all be icons. Anyone who takes their skills and applies them to something larger than their life becomes a hero, a metaphor that others can relate to.

John Lennon did this so well.

Green builders do this too. They take a mundane brick and mortar activity and apply it to a vision that heals the world.

This week I applied an earthen floor to a clients house. It was risky since I don’t know of any in New York and it is uncharted territory. But it was great. I know how to pour a concrete floor like traditional builders. I took that skill and applied my vision to turn New York green. Out came an earthen floor.

Imagine…if everyone in New York poured earthen floors instead of concrete ones. You may say I’m a dreamer but my client is one too. And our dreams became a reality this week. The floor is very real. Very green. Very inspirational.

John this floor is for you.


Eco Brooklyn Applying An Earthen Floor To A Harlem Townhouse

Milk Paint and Clay Sealer

Eco Brooklyn uses a lot of natural coatings on our Brooklyn brownstone walls, among them Milk Paint and clay. Both milk paint and clay are both matte finishes and anyone who has painted using matte paint knows that it scuffs a lot easier than glossy paint.

So when we want a more durable finish we seal the coating. But we don’t want to seal the pores. We still want the coating to breathe. That is the wonderful thing with natural coatings. They slowly absorb and release humidity in the room, helping to keep the room more comfortable. Sealing the surface will reduce this porosity but you get a more durable surface in return.

Sealing clay or milk paint is easy and there are many ways to do it.

Wax is a good one. For example pure carnauba floor wax. Pro applicators use Bioshield Floor Wax a lot on top of the American Clay and lime plasters. We don’t like American Clay because you are paying for the name. We prefer to mix our own clay. But Bioshield Floor Wax is great stuff.

Now that I have started keeping bees I have my own wax. I melt it down and mix it with Citrus Solvent, which is a natural alternative to mineral spirits. You can’t beat the feeling of using home made products! And clients love that extra touch!

If you can find it, Black Soap used to be popular but that comes from Africa and there are local alternatives. You can even use household soap or dish soap since they contain oils that impregnate the wall and harden.

Along the same lines you can use polymerized linseed oil, either alone or mixed with wax. Linseed oil makes a nice hard protective coat.

Another option we have used is wheat paste. We boil up some flour and water to make a milky paste and paint that on the wall. The wheat dries and hardens creating a clear protective coat that still breathes.

We have also used AMF Safecoat as a clear protective coating. They specialize in natural coatings.

The point is that there are many ways to coat a wall. Paint from the hardware store is one way but there are hundreds of other ways and many of them are much more ecological and just as nice, if not a lot nicer.

Good Clay Mix for Brooklyn Brownstone Wall

Here is a great starting point for making clay wall material.

2 parts sand (mason or graded sands but have a few different sizes 70-20-50 meshes)
1 part clay soil (screened through 1/8 to 1/4 screen to get the bigger bits of stuff out)
3/4 to 1 part chopped and screened straw or recycled saw dust from the job

Spread a sample as big as you can on the surface you intend to work on to see if this is too dusty (not enough clay) or cracks easy (too much clay)

You can apply such a mix up to 1/2 thick, it will cover lots of irregular surfaces. You can change the mix as you wish or add natural pigments. I like the colors from

It is really fun to explore the best application for the specific wall at hand. It changes day to day. And these materials are so forgiving! Eco Brooklyn is a professional clay wall applicator for Brooklyn brownstones, but truth be told anyone with the time and interest can do it.

Clay Wall Application For Brooklyn Brownstone

We have been getting really into clay wall applications for Brooklyn Brownstones. Brownstones have a lot of brick walls which lend themselves really nicely to clay wall applications.

Here is an order of clay we just got.

We love to mix different combinations to see what comes out. The trick is to find the right amount of aggregate – sand, marble dust, dolomite, saw dust etc – with clay.

Clay is a very absorptive material, which is why it is so wonderful It breathes. But that also means it expands and contracts dramatically. If you don’t make the right mix your wall will look like a dry lake bed:

lake bed

If you seal it this can also look really cool, though. That is the great thing about the whole process. If you have control over the clay it becomes your creative tool to make really beautiful wall applications.


One of the things we find goes really well with clay is casein powder. It acts as a great stabilizer to help keep the clay together. And it can be the base to carry the color. We are using a lot of color milk paint from It is really great stuff.

Here is an example of a clay wall application over a Brownstone brick wall. It is a very thick layer with lots of saw dust. It looks very beautiful. But we wanted to explore more so we then put a second coat of finer clay mix and added a little “Sea Green” milk paint to give it color:

Here it is on the wall:

Here we are putting the base coat of clay over a brick wall that was sealed with a rough layer of Thoroseal to hold the crumbling wall together.

We mixed this batch of clay wall application with “Pumpkin” Milk Paint coloring.

A close up of the clay mix applied to the Brownstone brick wall:

Depending on the kind of clay you use in the wall application the color can vary quite a bit. It can be a warm earthy color if you pick say, Brooklyn Red, or a much whiter almost gray if you pick something from upstate. The great thing is that there is a lot of clay on the east coast to choose from.






I wouldn’t say applying clay is easy since you need to know the right mixes and those vary depending on a lot of factors. Is the wall in the sun or shade, is the primary surface rough or smooth, absorbent or not, is the room ventilated or not, high traffic or not, etc.

But at the same time it is an ancient art. In fact it is the earliest art humanity has ever done: ancient cave paintings are made from clay. And there is something deeply familiar about covering your hands with mud and smearing it on the wall.


Clay Wall Application for Brooklyn Brownstone

Clay is a wonderful substance. It literally sucks the toxins from your body if you put it on your skin. When eaten it stabilizes your stomach bacteria to healthy levels and is full of nutrients. When put on walls it gives off negative ions and helps stabilize humidity in the air. Negative ions are the same elements in the air after a cleansing rain that make life feel wonderful and new.

Ever since people lived in dwellings they have put clay on walls. Here is an 1853 drawing of the city Timbúktu which is entirely built out of clay.
Timbúktu 1853

As green builders in Brooklyn we were excited to start using clay on Brooklyn brownstone walls. It seemed so green! When we looked around there was only one place we found that offered clay wall applications. It is a company called American Clay out of New Mexico. They offer a wonderful product.

But we had a problem with using the American Clay product in Brooklyn, NY. It is not a local resource. To truck mud half way accross the country seems a total abuse of energy.

And then there was the issue with regional building needs. New Mexico is full of clay walls. The Indians have been doing it for a very long time. Brooklyn does not have clay walls. There is a reason for this. A Brooklyn brownstone is a very different ecology than a New Mexico adobe.

Brooklyn, unlike New Mexico, is much more humid. Clay absorbs water and expands drastically. This means that clay walls in Brooklyn are going to suffer from cracking.

The other thing is the bastardization of a building technique. Putting clay over earthen adobe walls is one thing. There are a lot of reasons why you want to do that. Putting clay over a sheet rock wall in Brooklyn is a totally different thing. You have taken the clay out of context. There are many reasons why you don’t want to do that.

The main one is the huge importance to build with local materials. If you live around stone, build with stone. If you live in a forest, build with wood. These are the natural materials of the environment. They resonate locally and will work better.

The moment you put clay on a sheet rock wall you are working with concepts and not reality. You want clay because you have heard it is a really cool green product not because of any practically building need.

Despite all this, American Clay is telling the world that their product is great for Brooklyn. So we kept researching.

And as it turned out one of our clients asked for it. A certified American Clay installer did the job.

First they primed the sheet rock with their primer which makes the clay clink better to the rock.

Once done the clay looked great.

But it also cracked.

The stuff cracked all over the place…..the client is pissed, the installer is blaming the clay and American Clay is blaming the installer. They are all miserable.

And it turns out that this happens all the time. We have since heard from almost all the local American Clay installers that cracking is a major issue in Brooklyn.

Bottom line, American Clay is good for some parts of the country but not Brooklyn.

But we still felt that clay has its place in a Brooklyn brownstone so we kept researching for an American Clay alternative. We wanted local and since there is no local clay wall supplier we did what Eco Brooklyn does best – we got creative.

We bought 500 pounds of various earth products – silica dust, dolomite, quarts dust, coarse sand, white sand, fine sand and lots of clay. Clay from Massachusetts, clay from NY, clay from Florida, clay from Pennsylvania. Warm clay, white clay, gray clay. Oddly enough we didn’t get Brooklyn red clay?!! We wanted something lighter since Brooklyn brownstones are so dark and we are obsessed with light.

But we will probably realize our folly and order some Brooklyn red too.

This has led us to a wonderful discovery of what clay mix works for Brooklyn. Here Gennaro Brooks-Church is applying an Eco Brooklyn clay mix to a wall.

Here is an example of a wall with clay application.

Here is another with some color. We kept the color subtle since we were still focusing on getting the mix right.

We made a lot of mistakes.

But we have honed it down and are getting great and exciting results! More on that in another post!