three cob floor experiments

There are multiple floor experiments going on up at the Allerton Abbey wofati at the moment, and Jen is here to explain what's going on with the current state of the floors. We have a cob floor section that is nearly done but doesn't have its finish layer yet, and we have the lower cob floor that does have its finish layer. The cob floor section that isn't finished yet is also somewhat experimental because we wanted to make a plastic-free floor. All of the other sections have a plastic layer as a vapor barrier, made out of old billboard tarps that Fred salvaged. Instead of using plastic, we laid down some boards to keep the cob from sinking into the gravel below and becoming hard to work with. Time will tell if this will work as a plastic-free alternative for making natural earthen floors, and hopefully the wofati design will shed water away from the house well enough that a vapor barrier won't be necessary.
We learned a valuable lesson on the lower floor when it comes to finishing cob floors with linseed oil. In our earthen floors book, it recommends that you apply the linseed oil until it pools on the surface and stops absorbing into the floor. Jen ended up adding about 18 coats of linseed oil to the floor before she ultimately ran out of oil and gave up. The surface now seems quite saturated and oily to the touch, however in the process of brushing on the oil, sand was being rubbed out of the finish layer in the areas where it wasn't burnished. Fred burnished half of the lower cob floor with the finish float before the linseed oil was applied, and even though it didn't seem like it at the time, burnishing really makes a difference in the finished product! Now we know.
Last but not least, we have our very experimental sand and linseed oil floor. This is a floor that Paul thinks he heard about once somewhere from someone, that possibly might exist in Japan. It's essentially sand and linseed oil, mixed together, leveled, and then tamped down. The first several layers of sand and linseed, are lightly oiled with oil raked in, and then tamped down and leveled. Then we mixed up a final layer of sand with a significantly higher proportion of linseed oil, and water. This mixture was a lot easier to level and burnish as it was a lot wetter. The final touch was a few more layers of linseed oil to really seal in that surface, and hopefully make a waterproof floor that could be mopped. It's definitely been a work in progress for a while as we had some sprouts pop up from the sand, as well as a mouse (or squirrel) that got a taste for linseed oil, and started to eat the floors because of it. All in all, though, it seems to be holding up well, and we'll see how this experiment turns out!