Kevin McCloud’s Man Made Home – Cheese Floors


Posted by Jeffrey | Posted in Blog | Posted on 10-10-2012

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I was so very excited to hear about Kevin McClouds new four part TV series – Man Made House. Its a show that combines many of my loves. Kevin McCloud, building an off grid cabin in the woods.

Kevin’s show: ‘Grand Designs’ first peaked my interest in owner built homes and put the idea of someday building my own firmly in my head. (Ben Law’s Grand Design was a big turning point in how I viewed the home, what it should be made from and how it should fit into the landscape!)

I’m really glad that this show is touching on off grid living, alternative energy sources and recycled/reclaimed materials. It’s definitely a humorous approach, using wacky techniques. But as the cost of oil rises these are becoming more and more viable options.

Having laid several earthen floors and being a huge advocate for them, I am really excited to see the inclusion of an earthen floor in the cabin.

On so many levels earthen floors are pleasing to me:

  • Having a large earthen mass as your floor means that during the day, the floor will be storing heat from the sunlight that hits. As the temperature cools off overnight the floor then releases the heat back into the room. This acts to regulate the temperature in the room, keeping it cooler during the hot days and warmer during the cold nights. The analogy of a rechargeable battery is often used. (for more information on this thermal mass effect read here)
  • The feeling of walking on the floors is another big draw for me, it’s warmer than concrete and can be textured or smooth depending on the finish you are after. Without getting too hippy about it, it feels like a connection with nature.
  • But the most appealing part of earthen floors, is that you have most, if not all of, the materials right on your building site. You probably dug out most of what you need when you dug your foundation, making them very cheap.
    It’s quite literally, dirt cheap. (ho ho!)

Most earthen floors are a mix of sticky, aggregate and fibre. This is usually clay, sand & straw.
Something that sparked an interest for me was the inclusion of raw milk in the floor mix. This may seem a bit of an odd inclusion, but Casein is often used in earthen plaster mixes. Casein is milk protein and can be used as an additive to clay plasters or various paints to strengthen and prevent dusting.
Casein makes up about 80% of the proteins in raw milk so it makes sense why mixing in the raw milk would provide a good floor strength.

It was a shame that the possible reasons for the floor cracking were not mentioned. It was left as a bit of a failed experiment, when actually with a couple of small changes the floor would have turned out beautifully.

The mix that Kevin used would most likely have turned out perfectly for a thin finish coat. The lack of any sizable aggregate when pouring a floor 4 inches deep would lead to cracking alone. Kevin used chalk as an aggregate, which is a very fine powder. A better material would have been masons sand with it’s larger particle size. (for a base pour, then going to the finer aggregate for the finish coat)

The amount of clay binder (This is found naturally in the sub soil he dug up) in a floor should be somewhere in the 10-15% range.
The mix that Kevin used was 1 part sub soil to 1 part chalk, which could well be the right ratio based on the clay content of his sub soil but was not discussed.

You can test the clay content by performing a shake test, or simply creating a few test batches varying the amount of aggregate you add. If your test samples crack, there is too much clay. If they crumble or are dusty, then there is too much sand.

The steps to finishing an earthen floor that make it waterproof, mop-able and tough are to oil it, using linseed oil or similar. This forms a crystalline structure in the floor as it sets and provides a tough top layer. Then applying a wax layer will provide extra protection.

I hope the show revisits the floor in the last 2 episodes, it is a great opportunity to bring the idea of earthen floors to the masses, it would be a real shame to present it as an old failed method, when in actuality when done right it provides a fantastic, vernacular floor system that costs next to nothing.

Comments (6)

Have always enjoyed Kevin McClouds program but am particularly interested in his current project as I aspire to do something similar . Would love to learn more about natural building etc , especially straw bales housing and natural insulation . Cheers Greg

Thank you so much Jeffrey for writing in such detail about that alluring concept of Kevin Macleod’s cheese floor. His program gave very few details and his website gives even fewer!
I would love to use this process myself. Your information has made that dream more accessible.
Thank you. Diane, New South Wales

It seems this is the only website about cheese floor :)
I missed the samples and some explanations about the cracks too.
Thanks for sharing your thoughts about them.
What about the hair? I had the impression that they didn’t put enough hair in the mixture.
Sydney, Australia

I have no personal experience with using human hair, but I have heard it said that it has a tendency to clump together.

Handy tips above, as well as Diane’s comments on the paucity of details in Kevin McCloud’s website (saves me searching it). Anybody able to give ALL the recommended proportions of sticky to aggregate to fibre.
I live in Spain, where goats’ milk would be easier to source – is its casein suitable? Should fibre be chopped? If so, to what length?

I’m about to start laying a floor, would love answers pronto!

Jo, La Alpujarra, Andalucia

Hey Jo,

Sadly in natural building recipes don’t really work as your materials are going to be different to my materials. You clay could be more pure, or your aggregate may, or may not have clay in to affect the mix.

Your best bet is to mix up some test batches and create test bricks the depth of your intended floor pour. Recording the ratios carefully you should be able to work out your best mix. If the sample cracks, then there is too much sticky, if the sample crumbles then it has too much aggregate. Try a starting point of 3 sand to 1 clay and experiment from there.

I would also spent time reading up on earthen floors, as the casein is a small additive to regular floor mix.
Ziggy wrote a good blog on his floor:

I have never personally used Casein in floor pours, But I have been very satisfied using a plain earthen mix then linseed oiling the floor to give hardness. I’m not sure how even the cheese floor would perform without a linseed treatment.

Fibre should be chopped and screened for the final layer, again it depends what your fibre is!

As for the goats milk, A litle research shows that ‘goat’s milk contains only trace amounts of an allergenic casein protein, alpha-S1, found in cow’s milk.’ so perhaps not.

Good luck with your floor!

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