We used about 35 gallons of linseed oil for our 500 foot sqare earthen floor. This was over the course of 4 or 5 coasts. It is harder to say specifically how much 'per coat', as the cob absorbs the linseed oil much more rapidly at first. I would reccomend thinning the linseed oil with citrus thinner for the first coats, to get deeper penetration. Maybe like 5:1 ratio. For the final coats, we added beeswax to the linseed oil, which I would reccomend.
We sourced our linseed oil raw, from a company called Montana Vegetable Oil. This was 8 years ago, and they may not be in business anymore, I havent been able to find them lately. The oil came in 5 gallon buckets and was vastly more economical than purchasing in smaller quantities from natural building type suppliers.
There are true experts on this stuff though, unlike me, and I would definitely consult with one before you begin. Lots of ways for things to not quite turn out right.
Do you remember how you found the company as well as approx. how much you paid for the oil?
Location: 6200' westen slope of colorado, zone 6
posted 5 years ago
I dont recall how I found the company, sorry, it was 8 years ago and there has been alot between my ears since then. as for cost, I recall it being dramatically cheaper buying it direct from the agricultural processor. price was maybe about $40 for 5 gallons, plus shipping. I am sure it is much much more expensive now, as everything building related and agriculture related has really skyrocketed in the past five plus years. I edited my earlier post with some info my wife remembererd so re-read that please.
hope that helps-