Here is a photo essay of an earthen floor installation we recently did.
The earthen floor was for a Harlem client whose oak floor had been damaged by termites and leaks. We stripped the moldy walls, ripped out the floor and fixed the leaks. We then lay ruble on the floor to act as a drainage layer for water.
We used a mix of broken toilet bowls and junk rock from another job of ours.
On top of the ruble we lay salvaged insulation EPS insulation board that is ok in wet environments.
The foundation for the earthen floor is now ready.
On top of the insulation we lay a thick plastic vapor barrier that stops humidity and other harmful gases from seeping up from the earth.
Next we prepared the bottom layer of earth. This was a small amount of sand, a teeny tiny amount of cement, and huge amounts of earth from the same job site.
We used only filtered earth for the earthen floor.
“Traditional” earthen floors use straw as a fortifier but we figured straw would be a great snack for termites. So instead we used cedar chips which don’t taste as good to termites.
We also added some concrete bonder which is basically wood glue and helps bond the earth together.
We mixed it all up and put about five inches of it onto the foundation. This layer is the base layer of the earthen floor and is to give the floor strength. We packed it down with a pounder.
We let the base coat of earthen floor dry. This took a couple weeks in the humid summer of Harlem. Next we put the top coat. But before we did this we decided to do a little preventative work against termites. Below is a board eaten through by them that we had removed.
Around the corners of the room we sprayed boric acid, which isn’t toxic to humans but gets into the joints of bugs with shells and really annoys them. It is the bugs version of poison ivy. They stay away from it.
Now that we were less worried about termites we decided to go the traditional route and use straw in our mix.
Typically you shred straw for the earthen floor. But we didn’t have a shredder on site. We went out and bought the biggest and fanciest paper shredder but apart from being entertaining it did little to help our cause of installing an earthen floor containing shredded straw. We returned the shredder and honestly told them we hadn’t shred a single piece of paper.
The earthen floor mix has the consistency of thick mud once you add the water.
However the earth from the job site, like much of New York earth is rich and dark, high in organic matter. It is not like your typical earthen floor that is typically from the South West and has more yellow sand and reds from iron deposits. So instead of bothering the client with such subtleties we decided to make the earth look more stereotypically earthy by adding terra cotta concrete coloring. This is sort of like buying a little xmas tree with that fresh car scent for your used car. Sort of.
But we mixed the color in only slightly in the hopes it would cause a marbled effect in the earthen floor, which it didn’t.
We plopped the earth down onto to the thick lower layer. You can see the stripes of color.
We then troweled it out over the earthen floor. The upper finish layer is only about an inch thick.
Once done we let it alone for two weeks to dry.
And then we let it alone another two weeks to dry some more…New York in the summer is very humid. During this time it is very important not to step on the floor.
Once dry it was very much lighter.
We then added the magic. An earthen floor is just dried mud until you add the very fancy, very expensive natural mix of oils.
Instead of mixing our own this time we decided to experiment with a pre-mixed product from Land Arc. It is very high quality wood oil but works great on earthen floors.
We brushed the oil on liberally. We gave the earthen floor as much as it would drink.
The reason the floor dried with such a light color is that the silt in the mix rose to the surface during the troweling process. The heavier darker particles fell below the very fine layer of top silt. If you walk on the floor before it is dry you rub away the silt. But you can’t see this until you apply the oil. The oil seeps in much deeper into the larger darker particles than the silty top layer. This makes the larger particles very dark. It is a little like painting with invisible ink. You can’t see it until you put a special light to it.
Lo and behold somebody did walk on the floor!! We are way into the rustic look but this look was even too rustic for us. It looked like we had accidentally spilled paint on the floor or something. Not to worry. We were unfazed.
And we promptly proceeded to scrape the entire floor!
The end result was a beautiful leathery earthen floor. As New York earthen floor installers it is amazing to see how every single earthen floor is truly unique. There is no floor in the world like this one. There are too many variables. We just try to keep the standard high every time so the variables work with us instead of against us. Below is the finished earthen floor. The next step is to put the moldings on the walls.
An earthen floor is a very special thing. It is the very oldest floor humans have every made. They mix in all sorts of things – animal blood, herbivore animal dung, plant colorings, seashells, decorative pebbles, oils – and each item adds to the unique qualities of an earthen floor.
Our earthen floor installations may not be as exotic but that is mostly because we work with local materials and animal dung isn’t common on the streets of NY, although if we lived near one of the stables we would try it. Hmmm….maybe we should.
The metaphoric beauty of an earthen floor is its reminder of our immediate place. The earth we stand on right now can’t be more apparent when you are standing on an earthen floor. It is a grounding and centering experience.
Like fire and water, an earthen floor is primordial, connected to a long tradition of human living dating back to the cave dwellers who over the years I am sure made beautiful earthen floors as they compressed the earth with their wet bare feet and sealed it with dropped animal grease from their fires.
There are two kinds of green building: high tech and low tech.
High tech is fancy windows and energy efficient dishwashers. It is about looking to the future for improvements. Low tech looks back for wisdom. Low tech is salvaged wood and designing for sunlight but the most low tech of all is an earthen floor.
It has a simplicity and timeless green building elegance that no energy efficient air conditioner will ever match. An earthen floor in New York city is a counter balance to all the high tech that surrounds us. It can help ground us, literally.
I actually didn’t think too hard about the metaphysics of earthen floors but rather got into them one day when a client asked me to install a concrete slab in their basement, by far the most popular option, in fact the only option here in New York.
I decided to calculate the CO2 produced by one concrete floor for your typical brownstone. I was flabbergasted to find it released almost one million cubic feet of CO2! You can check my math here. I have rechecked it several times and it seems right. Cement despite its many wonders produces huge amounts of CO2 during its manufacture.
This really made me see that an alternative to concrete is important for Brooklyn cellar floors. I decided that even if earthen floors are not as hard as concrete the benefits far outweigh the cons of cement for the planet. An earthen floor is hard enough for most needs – about as hard as a wood floor -, it uses up earth that often gets taken out of the very same cellar anyway, it creates no harmful byproducts, it uses up no fossil fuels and so on.
The big issue is price. In third world countries people pick earth floors over concrete because it is cheaper. But there labor is practically free and any amount of money for concrete is considered expensive. An earthen floor is very labor intensive and uses a free material so it is ideal for poor countries.
In New York labor is not free. Labor is almost always the biggest expense on a construction site. It you can get expensive concrete into a cellar in one day it will always be cheaper than workers spending weeks installing an earthen floor.
I’m still working on that dilemma. I and my clients are very willing to spend more for a green product because most of the time it really isn’t more once you factor in the hidden costs of the non-green alternative. How cheap is that cheap and perfectly clean wood at Home Depot if the cost is deforestation? When you look at it that way the ugly salvaged wood looks pretty nice.
But there is a limit. Right now Eco Brooklyn has not installed enough earthen floors to know if a New York earthen floor can cross over that boundary between novelty and mass market price appeal. The mass market wants to be green, but only if they can also pay their rent and watch a nice movie when they want to.
But the numbers are close enough to look further… as we keep installing earthen floors with the early adopter clients who may not be rich but put their money where their green priorities are Eco Brooklyn hopes to find the earthen floor installation method that makes it easy for the rest of the population to financially fit an earthen floor installation along side their rent and nice movie expenses.
We remain hopeful. It makes too much sense to pick an earthen floor over a concrete one not to find a way for it to work.