Tuesday, June 16, 2009

In Praise of Walnut Oil as a Finish for Earthen Adobe Floors

Last January, after laying down an earthen floor in the adobe home we were living in, the question of what to finish the floor with arose.  In New Mexico adobe floors were traditionally sealed with ox blood. Today, the  choice both here in New Mexico and in contemporary cob building in England, is to seal the floors with  several coats of boiled linseed oil diluted with a thinner such as turpentine or, the more natural alternative, citrus solvent. To this is added a final waterproofing coat, a polish made from a mixture of beeswax and linseed oil.

Linseed oil is a gummy derivative of the flax plant which must be thinned to help it penetrate the earthen floor it is being applied to as well as to speed up its drying time. At the time of year that we needed to seal our floors, the freezing temperatures outdoors prevented us from being able to adequately ventilate the room we were working in, making the choice of linseed oil unattractive because of the strong and long-lasting fumes the oil gives off while drying. While researching alternatives to linseed oil  both milk and blood meal were named as alternatives,  but as neither fully answered our requirements for a beautiful, long-lasting finish that we could mop, we began to consider walnut oil. In our research we had found no reference to walnut oil as a finish for an earthen floor,  but we had recently finished our kitchen cabinets and counters with the oil on the suggestion of a friend, colorist and inventor Stephen Auger. Having used it on wood with great results, we thought it might work well on an earthen floor. For our cabinets we had applied food grade walnut oil which we purchased at the local food co-op. We puit it on with a paint brush, let it soak in for  a couple minutes and rubbed any puddled areas dry with a clean cotton rag. The oil gave the wood a warm oiled glow and  served also as a stain and water repellent. Although walnut oil is said to polymerize(fully dry and harden) over several months it was dry to the touch  almost immediately and left no sticky or smelly residue. Relying on  this experience with walnut oil, Auger's experience, and with previous experience oiling floors with thinned linseed oil we decided to take the leap of faith with the unknown and ordered 5 gallons of food grade walnut oil online. www.libertynatural.com. 

The area we were working on was about 300 square feet. We applied the oil generously with a paint  brush, allowing it to soak into the earthen floor, occasionally going back and wiping up the puddled areas. The next day we gave it another coat, not noticing any difference in the floor's willingness to take the oil. On the third day we moved  ourselves and furniture back into the room which is both our kitchen and living room. With the walnut oil finish the floor  had taken  on a luscious chocolate brown color and though not dry ( we tracked oily footprints onto the hallway saltillo tiles, which we simply wiped clean) we were pleased.
Ideally at that time we would have liked to have applied another coat to achive a richer and more protective finsh. A coat we did apply the following summer. Today,a year and half later the floor has gone through weekly moppings with water and a little castile soap and still looks great, thus negating the need for the beeswax polish. As a footnote, we are a household that rarely takes our shoes off when coming in from outdoors, something we do frequently throughout the day. 


Unknown said...

This is great info. Kurt Gardella turned us onto your blog- he showed us how to repair some holes in our mud floor and told us about walnut oil as an alternative to linseed oil. So I think we'll try this. We might have met last year at the Adobe conference- we were filming it.

Jill said...

I tried to leave a comment about a week ago, but I'm not sure that I succeeded. We are just finishing an earthen floor in our kitchen - the "dining room" area, not the cooking area. Although linseed oil worked great on our handmade adobe hearth, the fumes were noxious for a long time. Could you please update us on your now longer-term experience with walnut oil - preservation (including hardness and cleanability) of the material, absorption (rancid smell after the fact?).

Thanks you.

(I'm providing my email address in case you need it - pls delete before posting commment - thx).

Jill said...

Hi. Inspired by your experience, we would like to finish the adobe floor in our kitchen with walnut oil. We used boiled linseed oil on our hearth last year and were impressed with the hardness and finish, but the fumes were noxious for a long time. Would you please give us the benefit of your now longer-term experience with walnut oil? All feedback is welcome, but we are especially curious with the ongoing hardness and cleanability of the finished product and we wonder about absorption and whether the oil ever took on a rancid smell.

Thank you.

Liza Macrae John Corcoran said...

We had no problems with the walnut oil. We would mop the floor weekly with Murphy's Oil soap. It did develop a smell, it could have been rancid but we didn't find it offensive, more nutty. The smell seemed to be activated by the sun shinning on it. I kept thinking I was going to polish the floor with beeswax but it just looked so good.

My new found love of walnut oil took me to making my own oil paints with pigments and painting, more like staining all the interior raw wood doors and the exterior windows. We have since sold the house so this info is a year old but this was our experience after 2 years.

Corinne Segura said...

Could you tell me what kind of pigment you used to get the chocolate brown color?