report on my earthen floor - 14 months of living on it

So, thought I’d write up a small report of stuff I wish I’d known before I started my floor, specifically about how it wears.

I have a cob house, about 1100 sq-ish ft, three levels, with radiant tubes for heating. Here in the sandstone hills in northern California, we dug down below topsoil, put in about 44 tons of ¾” gravel (that’s about 6”-14” deep, depending on how much leveling we had to do) and then put in a cob sub floor made from clay and ‘road-base’, which is a clay-full crushed gravel they use as a road top – sort of rural blacktop. That layer was something like 4” thick. Then tubes, then 1 ½” of fine sand, clay, horse manure mix “poured in” – that is, put in pretty wet and trowelled smooth.

When that had completely dried, I did one room one way, and the rest of the house another.
The bedroom got 6 coats: the first 100% oil, then I waited a week, and did a coat thinned to 75% with fancy citrus solvent. Waited a week, thinned again, to 50% waited a week, then did maybe 2 more coats at 50%, waiting each time until it dried.

The rest of the house was done (each room separately) ‘all at once’. Starting in the morning, I slopped on a heavy, heated coat, and as soon as it wasn’t puddled, did another, and another and another, using less (but still 100%) each time. I got 6 coats on in a day. Once everything dried, I did a fancy wax coat, buffing as much as I could.

Unfortunately, the one room done differently is the bedroom, which gets the least wear, so it’s not a good comparison.

They all look pretty good, with a dark chocolate color. The bedroom seems to be a bit shinier, which it turns out I like.

However, what I see in my kitchen (where most of the action is) is a floor that is NOT hard enough. The wooden kitchen chairs, when someone sits in them (and, surprise, that happens a lot) will leave (permanent) dents in the floor, deep enough for a quarter to sit in. I’ve dropped some things, and they’ve left noticeable dings. Basically, it’s not hard enough. That’s pretty frustrating, as I don’t know how I can repair it.

If I could do it again, I’d figure out a way to spend more time and get it harder, especially in the kitchen.

Tys

thanks a lot. that's really helpful information.

would adding some tiles or flat stones or wooden cobbles or planks help with the dents? maybe place them where your tables and chairs are. I don't have much experience with this, so I'm just throwing ideas out there.

Ditto Tel - information gold. Thank you.

Again, like Tel, I'm not an expert. But here are some thoughts:

1) Try to reduce "point loads". Some things will leave marks on almost _any_ floor. Womens' high heels come to mind, but you probably don't have to deal with those. <g> But anything relatively pointy will do it because it concentrates all the pressure on a small spot that raises the PSI load tremendously. Maybe you can enlarge the bearing area of the chair legs, attaching some hardwood "skates" 1-1/4" or so across. Perhaps if you can deal with one or two specific areas that way the rest might be quite adequate? Many cultures have people leave their shoes at the door and perhaps you can joint them?

2) Put on a thin very hard surface. It sounds like the floor is solid enough to support weight if it's spread out a little. IIRC the rule of thumb is that force (weight) will "spread" at a 45d angle through solid material. 1/4" tile would probably do the job if your philosophy, means and elevations permit the floor to rise about 3/8-1/2". There are applied materials that are very hard but I can't list off the ones that you should look at. Why not talk with real experts on this - join the talk group at "Fine Homebuilding" magazine's website and pose your problem. Ie. floor surface too soft, need thin hard surface applied on top; could also ask who else might have ideas. JLC (Journal of Light Construction) also has a webpage and although they are mostly a peer group of pros, you might give them a try also. I suspect that plasterers, concrete guys, masons and tile people might have something to say.

3) Vinyl or linoleum tile or sheet goods, maybe over a poured or troweled skim coat of something hard - 1/4" or less. Linoleum is supposed to be a very natural product and as I understand it is considered top-o-the-line flooring used mostly in really hard use areas like schools and convention halls. Priced accordingly, unfortunately.

4) Seems I recall that rolling (to compress) or buffing a floor can harden the surface but I'm way out of my knowledge level here.

Rufus

I don't have experience with adobe floors yet, but in my experience with concrete, as well as clay plaster, compression is key. I've seen the difference recently in 2 separate rooms between concrete that was only screeded and one that was trowel finished. The trowel finish has no cracks, while the screed only developed long cracks. Same with clay plaster adhering to a wall.

The other thing that I thought of was drying time. Did you allow it to fully cure an all levels? Its possible that if the under layer wasn't fully dried, moisture was migrating up into the top layer and possibly getting trapped under the sealer. How soon did you fire up the radiant floor? What was your mix ratio and ingredients?

maybe you could tamper it?

I do not know about your floor but i do know that, if you put tile over it, the tile will conform over time to the existing dents or if ceramic they will develop cracks.

Generally self leveling compound or concrete is used, I doubt this will stick to the existing floor but like i said, i do not know your method.

I was thinking of the earthen floor problems you had and i remembered an old fashioned solution when i started thinking the problem was that you needed to spread out the weight of things on the floor.

Floor clothes. There is many ways to make them yourself...some use unnatural materials but you can choose to make one using all natural materials.

Just another idea to keep in mind.

Tys,

Do you think you could post of picture of the floor? I have no experience with earthen floors, but find them fascinating.

Thanks!

I'll second the request for photos.

i third the photo request (:

i have an earth floor in my room now, not really my idea but i dont mind it really. my biggest problem is its totally uneven and since its been like this since about 1980s its purdy darn packed in! even with a hoe i hardly made a difference.
also mine is just packed dirt. nothing added.

You may wish to consider adding cork tiles, just in the area where the table/chairs are to take the impact. They are affordable, renewable, water proof, fireproof and look great to.

I have an idea for you. Mix a slurry of fire clay (as found at Axner pottery). They sell it dry by the bag. Put a thin coat on your floor and let it dry. Oil it after.
If you look at prure clay (like a potter uses) under the microscope, it is comprised of shale like plates that bind to each-other. This would be the opposite of sand which looks like a cube.
If you walk on a shale beach you don't sink whereas if you walk on a sandy beach you sink. So the more pure your clay is on the floor the "harder" it is. Put a slurry of pure clay down - something like a Hawthorn fire clay or just use any pottery clay that a potter would use to throw pottery. One of the bigger names is Goldart (don't use Redart - that is terracotta). It comes in a bag just like concrete does. This should get you a plate like structure like microscopic shale and be really hard. I'd test a spot to make sure it seeps into the floor a bit. If the thin layer just floats on the top of the existing floor, it will scale off. So it needs to go on so it binds to the existing earth floor.

If that clay isn't hard enough - there is no harder stuff.

I know this is an old post...but...my friend has a roof top garden, with an epdm roof. Rubber roofing and pointy things dont mix. They wanted chairs to hang out, took them forever to find, but something such as,

http://www.bing.com/images/search?q=Round+base+chairs&go=&qs=n&form=QBIR&pq=round+base+chairs&sc=4-17&sp=-1&sk=#view=detail&id=341BC03FD9B1313E3DAB1E073317911B12973134&selectedIndex=244

you could retrofit what you have maybe?