This week, under the tutelage of earthen floor master Sukita Crimmel, we installed an earthen floor in the garden shed. Sukita has written the foremost book on this subject, entitled Earthen Floors: A Modern Approach to An Ancient Practice. You can see more of her work on her website From These Hands.
A well-made earthen floor could be built with the following layers (from top to bottom):
The earth finish is a mix of 4 parts sand, 1 part clay, and 1 part cut straw . Spray down the gravel with water before pouring the earth finish. Apply the finish with wooden floats, then do a few swipes with a steel trowel. The next day, burnish and compress it with a steel trowel to give it more density and shine.
5-7 days later, when the floor is dry, you’ll want to oil it. Apply 4 coats. Sukita’s company makes an oil called Claylin Oil that you could use. Other options might be pure boiled linseed oil, but there may be some contamination of linseed oils generally sold in hardware stores. Besides the difficulty and fire hazard of boiling and applying large amounts of linseed oil, it’s also unclear how well it will penetrate. I am interested in doing some experimentation to find solvent-free and practical oiling solutions.
In the following video, Sukita discusses the steps involved in oiling an earthen floor. We are inside a neighbor’s farm office that was built by a prior year’s class. We went there to repair some cracks that had developed in the floor:
A week after oiling, sand the floor and then you can apply a coat of wax or another coat of oil.
To clean the floor, use oil based soaps such as Murphy’s oil soap or Ecover floor soap. If over time, cracks appear in the floor, you can repair them, as Sukita shows in the following video: