Earthen Floor Finishing Methods
Earthen floors have been gaining in popularity over the last two decades, in conjunction with the
growing interest in straw bale, cob, and natural home construction methods. Although still a
niche floor construction method, the technology is far from new and variations on the technique
exist all over the world. However, most earthen floors are comprised of the same basic
materials: sand, clay soil, and fiber.
Traditionally-built earthen floors in the southwestern United States were commonly finished with
ox blood for durability. Understandably, most individuals these days cannot or would not opt for
such a finish. Luckily, access to oil finishes means that a high quality, exceptionally durable, and
long lasting earthen floor is within reach for people interested in a beautiful flooring alternative to
wood, concrete, or tile. An oil finish makes the difference between what is simply dried earth,
and an earthen floor that can resist damage from foot traffic and moisture equally well.
If you’re interested in more earthen floor construction, we recommend picking up Earthen Floors by Sukita Reay Crimmel and James Thomson, who do an excellent job describing the process
and materials in detail. The following tips assume you want more information on the actual
finishing process, and how to create a water-repellent, long-lasting floor using our natural oil
finishes.
Why Use Linseed and Tung Oil?
There are several basic steps to a successful earthen floor finish. First and foremost is that you
must be certain the earthen floor is 100% dry before applying any oil. If you are unsure, do
yourself a favor and wait a little longer. Any moisture still present in the floor can be trapped
under the oil finish, resulting in problems down the road.
For all earthen floor finishing jobs, we recommend our Earth Finish, a blend of high quality
linseed and tung oils, citrus oil, beeswax, and pine rosin. We only use the best possible
ingredients we can find, and that makes all the difference for finishing an earthen floor. Also
critical is that linseed and tung are hardening oils -- you cannot use non-polymerizing oils and
expect a successful floor finish, since those will remain sticky and potentially go rancid over
time. Once linseed and tung oils fully polymerize (dry and harden), the resulting floor finish is
very resistant to water and daily wear. Water will bead up on the surface, and the floor can be
mopped clean without issue.
How to Finish an Earthen Floor with Earth Finish
Most commonly, four coats of oil are applied to a dry earthen floor installation. Starting at the
corner furthest from the entrance, the edges can be brushed in first. Do 3-4 coats around the
entire perimeter, and then move onto the main field. When applying oil to the main field, a
lambswool applicator pad or roller works well for pushing oil around the surface. You can also
use a sprayer.
The first coat can be heavily applied and should absorb readily. For a large room, you can
return immediately to your starting point and apply a second coat. If it is a small room, simply
wait until most of the oil has absorbed before applying again. Repeat until you have applied 4
coats, or to the point where the floor cannot accept any more oil. You’ll know you have reached
full saturation of the floor once significant puddling begins to occur. Using a dry, clean rag, wipe
up excess oil. The mottled oil pattern will dissipate once the floor has additional time to absorb
the oil, and the color will even out.
After the final coat of oil has been applied, it is best not to walk across the floor for one week.
After one week, test the hardness of the finish by trying to indent the floor with the edge of a
trowel or putty knife. If there is movement under the edge, give the oil more time to cure. If the
floor appears hard and dry, you can consider it ready for use.
This concludes a basic earthen floor finishing method. It’s also possible to sand or buff the
earthen floor once the initial finish has hardened. Additionally, you can use our Liquid Wax as a top coat to create a higher surface sheen. We will share more details on these techniques in a
future post. Until then, here are a few other helpful hints using our Earth Finish.
How Much Earth Finish Do I Need?
● For 4 coats of Earth Finish: Multiply 0.023 by the total square feet of earthen floor you
want to cover, this will give you how many gallons you need.
● For 6 coats of Earth Finish: Multiply 0.029 by the total square feet of earthen floor you
want to cover, this will give you how many gallons you need.
Additional Finishing Tips
● For spills, over spray, or to clean up brushes, use our Pure Citrus Solvent or other
solvent (Turpentine, Mineral Spirits, etc.).
● When applying oil, it is best to go barefoot or wear an old pair of socks you won’t mind
throwing out afterwards -- do not wear shoes during this process.
● Mask adjacent surfaces you want to protect during the finishing process with painters
plastic and tape
