Earthen Floor Start to Finish


The process of this floor has long been in the works.   I first tamped the earth beneath the building.   Then added a layer of cut polypropylene bags. Then 6 inches of red pumice ( otherwise known as scoria ).  The scoria has insulating properties and also acts as a capillary break from moisture of the earth.

Through the scoria layer I added a 4 inch perforated drain pipe, in case one day a radon gas evacuating system could be attached.  Then a couple layers of 4 mil plastic as air / moisture barrier. On top of that is 1 inch of of sand, leveled and tamped.  Then tons and tons of mud.  The mud base is at least 4 inches thick. A mixture of clay, crusher fines and straw.  Crusher fines are usually cheaper than sand; it’s the step before plaster or concrete sand, so there is less processing involved.  It has sand and rock all the way up to .25 inch. The diversity of the aggregate lends to a stronger substrate.   This would have been a good time to add pex tubing for future radiant floor heating! 
A few leveling layers of mud with finer sifted materials brought the floor ‘close’ to level.

Then 4 coats of alis  (clay paint ) with fine sand and clay. I still had some left over red clay from a cut off the road near Albuquerque, so I soaked it and whipped it with the paddle mixer for a few days.  The alis had 20% wheat paste mixed in for added durability. Then sponged it on, rubbing out any small divots in the floor. Hitting it with the pool trowel to work it in smooth.  As it dried I buffed the floor out with a piece of cloth to remove any excess sand or debris. Swept and let it to fully dry before applying the oil.

In the interest of future estimation I’ve found that .5 gallon of linseed oil will cover about 100 square feet. That is, straight, with out mineral spirits.  This is on a relatively smooth floor. The next coats were cut 20 -45 % with mineral spirits. In total I’ve placed 4 coats of linseed oil increasing the spirit content as I went along. The oil container was left to sit out in the sun for the day, so the oil was warm but not hot.  The oil was applied with a paint brush with great success, sometimes dumping oil on the floor and working it around. The earthen floor really soaks it up. Especially to first two coats. Before I was done with the first coat of oil it was ready for the next.  The linseed container says 12 – 18 hours before ‘dry’.  The next day I added more. It didn’t soak in as much, but it added a shiny coat. Windows open and waiting… god that stinks.

I’m interested in alternatives to boiled linseed oil. The stink seams to stick around for awhile. There’s organic raw linseed oil with out the noxious ‘drying’ chemicals. Perhaps in the future I’ll try that. Linseed, Walnut, Tung, Hemp and Perilla oils are all hardening or ‘drying’ oils. They create a chemical reaction with oxygen, leaving a tough, elastic film.  Citrus oil instead of mineral spirits may cut down on the stink factor as well. Remember! Rags and tools covered with oil can and WILL spontaneously combust.

After the oil has had time to cure, I’ll give it a coat of wax.  I hear tell of a linseed oil, carnuba wax, beeswax, paste wax mix. Also a 50/50 linseed oil and carnauba wax mix.  Straight linseed and beeswax. I’d like to experiment more with the super fine shiny finish.   This time I’m going to use the Howard Feed-n-wax citrus oil and beeswax product for the final touch.

14 Responses

  • garen ray says:

    My comment was directed @ Elena, since I am in Luna county & looking to build with cob as well, but anyone within 200 miles of Luna county are welcome to contact me. Looking to learn faster ways of building with cob. Thank you.

    (PS: if Elena reads this, please contact me; I would love to see your house. Thank you. raygun5150@live.com)

  • Elena says:

    Hey there,
    My partner and I just built a partially underground straw bale house in Luna County with an earthen floor. Sealed with several layers of linseed oil and mineral spirits. I want to seal it with Beeswax. What exactly is the process? Is it just a matter of melting the beeswax and mixing with linseed oil? In what proportions? Any information greatly appreciated.

  • betty in taos says:

    im afraid i put a little too much boiled linseed oil and mineral spirits (maybe a bad percentage) on my old mud floors….now its sticky….can anyone suggest how i can remove the stickiness?? thanks!

    • Greetings.

      I just read your request to remove the stickyness of your oiled floor.
      To get rid if the stickyness you can try to pour in a corner some methylated spirits (that’s what we call it here) on the surface this will disolve the excess oil and than you can remove it with a rag.
      After that you dont have to do anything because there is so much oil in and on the floor job is done for now.
      Meths is made from Ethanol which is an alcohol.
      I advice you to wear nitril rubber gloves as it will go into the system and may make drunk somewhat. Hope fully this will help or someone has given you some advice already.
      Regards Menno Besseling

    • That happened to me too.
      Kindra told me that one should get a bunch of rags and soak the floor until it will take no more oil.
      Then remove the excess oil before adding the next coat. Applications of oil and spirits should be done all-at-once, rather than waiting 12 hours.
      I think the excess oil is where the stickiness comes from. My floor eventually lost it’s stickiness.
      I wonder if a coat of wax would help?

  • Alis or claypaint can be made from a variety of finely sifted clays. That’s the fun of it! Colors. You don’t need much for a couple of thin coats.
    I collected some red clay and soaked it for weeks, whipping it with a paddle mixer. Then mixed the ingredients at a ratio of %65 sand and 35% clay. Wheat or rice paste as a glue and hardener, 2 cups per 5 gallon(?).

    Sometimes add cow manure, finely chopped straw, mica, whiting.

    Check out Carole Crew’s book Clay Culture for detailed recipes »

  • Jean Combs says:

    looks great would be very curious if anyone could give me more detailed infos on the alis claypaint recipe how much sand to clay in the process of doing a floor over here and like the claypaint idea a lot thanks paul

  • Ron Ringsrud says:

    Looks Great! I would love to hear from you in about a year to see how things are holding up.

  • paul says:

    looks great would be very curious if anyone could give me more detailed infos on the alis claypaint recipe how much sand to clay
    in the process of doing a floor over here and like the claypaint idea a lot
    thanks
    paul

  • Lampang says:

    Looks good. I made an earthen floor last year but unfortunately the termites – endemic where I am – ate right through it, though luckily this was in a test building (built to discover just these kinds of problems, so I guess it’s at least done its job). They’re little bastards and the only way I can think to get around it is to put in a concrete subfloor, which kind of ruins the point of the earth.

  • john says:

    Nice. We order 5 gallon raw linseed oil from a supplier in Washington. You can get it with orange oil added to help penetration. It works well. I am told the most important consideration when selecting oil is that it be a “drying” oil. This means that the oil contains lipids that will polymerize upon exposure to air or heat. Linseed oil is the most common.

    Kindra and I are in Black Lake. We will be working on the installation of solar panels for the radiant floors in the Black Lake Mountain Cottage. We look forward to seeing you either on the mesas or if you come visit. We will be calling soon.

    john

  • Liza Macrae says:

    The floor looks great as does the entire room. We put in pex tubing and never used it, that rocket stove looks like it will do wonders.

    We used food grade walnut oil straight on our floor, no thinners, I ordered it online in 5 gallon, and as it is odorless going on it does have a slight odor when the floor heats up in the sun. We wrote about it here http://ahousemadeofmud.blogspot.com/2009/06/in-praise-of-walnut-oil-as-finish-for_16.html

    Cheers Michael, missing NM Liza

  • ziggy says:

    Phenomenal color!

  • gaile says:

    wow your floor looks just beautiful! Thank you for such a detailed description of your experience.