Natural Floors

Janine Bjornson is a natural builder, practitioner and educator. She began her career in natural building when she trained with The Cob Cottage in 1996. Since then, she has taught over 65 workshops in Canada and the United States, from east to west. Her passion for building with natural materials bloomed out of her love for the earth, in conjunction with her concern for diminishing ecological resources and toxic buildings. As a result of this, Janine has devoted the last 14 years to immersing herself in the world of natural materials and the knowledge of how we can shape dwellings that are healthy, healing, inspiring, and beautiful. She has developed a penchant for natural paints, and plasters and loves the concept of “naturalizing” any kind of home. She loves to share this knowledge with others and this is evident in her enthusiastic teaching style. Janine has assisted in organizing 2 Natural Building Colloquia. She has presented at the Natural Building Colloquium in Bath, New York, Kingston, New Mexico, and Kerrville, Texas. She taught the hands-on natural building component of New College of California’s EcoDwelling program, and Dominican University’s EcoDwelling program. She lives in Sebastopol, California. www.claybonesandstones.com.

Questions and Answers

Q: Do you have some natural ways to seal adobe floors without using linseed oil?

A: You may use other oils instead of linseed oil. Hemp oil, walnut oil etc., I do not know of another natural option besides using oil. You may wax the final floor but oiling it first creates a very hard floor that is water resistant. I suppose you could try the traditional method of celebrating and slaughtering a goat or sheep on the floor. The proteins in the blood create a great sealer. However, I do not know anyone who has tried that tradition. Good luck.

Q: I am interested in finding out the rate of application of linseed oil on a 500 sq ft rammed earth floor. I hope you can help, no luck from an stores yet.

A: (Kelly) I can tell you from my own experience applying linseed oil on a poured adobe floor of about that size, that it didn't take as much as I expected. I might have used a couple of gallons at the most. I started out thinning the oil with odorless mineral spirits or paint thinner for the first 2 or 3 coats, then went to the straight stuff for the last coat or two. It is really a matter of applying the oil and allowing it to soak in as much as possible each time, and then wiping away any standing oil before it congeals. The local pros tell me that they are heating the oil on the first several applications to get it to penetrate better.

Q: I am in the process of buying a new house, but I want to eliminate carpet flooring from the bedrooms because I suffer from allergies (Doctors recommend to eliminate carpeting). I am thinking of replacing the carpet with cork flooring or the latest trend: wood laminate floors. Also, I am considering engineered wood floors. My concern is that these floors have polyurethane, teflon, or aluminum oxide layers...Is there a brand, or type of floor that would be more “healthy” (besides bamboo flooring)?

A: Due to your allergies it is smart to avoid carpets and anything else that could harbor allergens. Therefore, having a floor system that is smooth and can be easily washed and swept is the best choice. If you can not find a flooring option that is compatible for you due to the possibility of toxic binders and sealers, I would recommend looking at getting some reclaimed or sustainably harvested wood. This way you could install something clean, free of irritants and have the power to decide which kind of sealing treatment you would prefer. Make sure that you get FSC certified wood and not an imposter. For sealers I would look at Bioshield, or Livos products.

If you find yourself leaning toward the cork flooring I would suggest using a system that is not a "glue down" system, this way you can avoid those toxic glues. Instead, use the T&G (tongue and groove) system that can be nailed down. They even have a system of T&G that is a floating floor and avoids using the nails. All cork, and bamboo options are not the same; make sure you find out exactly what their binders are. EcoTimber has Cork and Bamboo, and they say the Bamboo is virtually formaldehyde free??? They can send you the specs on the product if you ask to find out exactly what this means.

Another range of options would be to install, rock, stone, ceramic tiles, natural linoleum, or recycled glass tiles. If you are buying a home with a concrete sub-floor you could even think about installing a poured adobe floor (earthen floor). This is a beautiful non-toxic option that many chemically sensitive people choose.

Q: I Live in South Africa where I recently came across a traditional corcoleum floor made of wood shaving (first layer) and saw dust (top layer)- compressed and bonded with either a natural resin or other material. Have you ever heard of this type of flooring method?

A (Kelly): No, I haven't heard of this type of flooring. It sounds like an interesting approach to creating a natural floor. I would appreciate learning more about it myself; if you are able to find out more, please let me know.

C: From what I can gather, it is a traditional method of flooring brought here (to South Africa) from England. The floor consists of two layers: One. Wood chips (planing room waste) is mixed with Magnesium chloride crystals and water (a slurry pulp) Magnesium Chloride and water solution is painted thickly onto rough concrete floor, and then the pulp is stamped and floated onto this (about 15-20mm). Two. Saw dust mixed with pigment (if preferred I guess) is mixed with Magnesium Oxide and water, same procedure (not too sure from here on)b 15-20mm thick This is left for a week or so, then sanded with a floor sander - somewhere (before or after sanding) the floor is washed down with I don't know what to stand for another two weeks or so and then sealed (don't know what type of sealer used) The finish is to die for, has a warm and almost soft feel under foot. I believe the floor is extremely hard wearing, resistant to everything and lasts for decades. Adherence is vital due to possibility of lifting (especially if under floor heating is present. If this sets you on to any information regarding corcoleum please let me know.

C: CORCOLEUM is the name of the company which manufactures industrial flooring. Corcoleum floors are magnesium oxychloride floors - usually used in industrial settings. In South Africa Corcoleum Flooring has been used as an alternative to wooden floors in sports halls. Also used in hospitals. Magnesium oxychloride floors are antiseptic and anti static, and can withstand great weight - many times the compressive strength of concrete - and is fireproof. It can be laid over wooden floors. Depending on the material used as aggregate it can be very much lighter than regular portland cement screed. Magnesium Oxycloride is used as a binder of wood or straw to make fireproof ceiling panels. In South Africa Corcoleum, which uses sawdust and wood flour as a filler (aggregate), has been used extensively in the restoration of old Cape Dutch homes. Mixed with the correct pigments the floor simulates a "cow dung" floor used by the early dutch settlers. The flooring is pleasant as it is easy to maintain, is "dust free", a good insulator (warm in winter and cool in summer) and resilient.

C (Gregory Kain): Corcoleum Flooring was started in 1925 in South Africa by a Hollander called Mr. G Kuyk he brought the process over from Holland. My father bought the company from him in 1963 ( Geoff Kain) and it has been in our family since then. Corcoleum is the name of the company and the product is called Maplette Flooring.  The floor is done in 2 layers first layer been of course sawdust mixed with Magnesium oxide (Magnesite) and Magnesium Chloride (MgCl2 x 6 H2O) both these products are natural products and when mixed together they start a chemical reaction and sets up hard. The second layer is made of finer sawdust, wood fibers and pigments again mixed with Magnasite and Magnesium Chloride. This process takes a lot longer in laying and is very labor intense. The total thickness of the floor is about +- 23mm thick. The day after the final layer is laid the floor then gets washed and then left for 5 to 7 day to dry out then it is dry buffed and sealed with a water based sealer. All of the products are natural and not harmful to the environment. The floor is 85% sawdust and was used mainly in factories but has become more popular in houses over the years. We can get the floor to set up to a strength of 35Mpa. The floor is also 100% fire proof. The floor is laid straight on to rough concrete a cement screed or old timber floors. For more information contact enquiriesATcorcoleum.co.za.

Q: One of our readers is frustrated to find it almost impossible to access organic adhesive and sealant for a wooden floor she is putting down in her home. I have tried through University academics in the British Isles but can't seem to help her and would really appreciate it if you could help or at least point us in the right direction.

A: I have been trying to find information to help your reader. I am not sure of the likelihood of finding an "organic" adhesive and sealer. I imagine that it would be extremely expensive if it exists. There are "natural" oil and wax finishes used for sealing, but I do not know if they are organic as well. She may try contacting: Green Building Store, 11 Huddersfield Rd, Meltham, Holmfirth, West Yorkshire, UK, HD94NJ, Telephone: 01484 854898 They have natural wood sealers and may be able to point her in the right direction for something organic.

Q: I read and appreciate your comments on bamboo. Its environmental friendliness makes me consider it for the floor in my home. I have, however, heard questions regarding formaldehyde off-gassing. My house is extremely air tight (but has an air-to-air exchanger to the outside), so off-gassing concerns me that much more. All manufacturers say that their bamboo's off-gassing is totally insignificant. They far exceed the European standards for formaldehyde. a) Is this standard safe, to your knowledge? b) How can I determine if the tests are valid?

A: (Kelly) I am inclined to consider bamboo flooring as a nice green alternative, but I don't know the answer to your question about European standards for formaldehyde.

C: Considering bamboo flooring is what awakened my concern about formaldehyde. In my opinion, once again the US standards, driven by whatever forces, are the lowest in the developed world. But bamboo, of course, grows in the developing economic world--even more dicey in my experience. As I understand it, they're are 3 main formaldehyde standards, rising in quality: US, European, Japanese. Bamboo is great, I think. Formaldehyde probably worse than we yet acknowledge. The companies in the US that sell bamboo flooring, at least as represented by their staff on the telephone, have not a clue about testing. One simple example: "We sent them a sample in 2000. I think the sample was about 6 months old." Does this mean there are no rules about how long ago the testing sample flooring material was produced?. If so...meaningless. Does it mean that after that one test, 5 years ago, they're trusting their supplier in China to keep the product the same--at extra cost to the supplier? Of course there is off-gassing of formaldehyde in many products. I wish I'd been more aware of this when I started my new home. But my last decision is the flooring. Safe bamboo flooring? I simply don't know.

Q and A (Kelly): I have tons of sand. Can I make great floors this way? Can I seal them and make them washable and water resistant? I'm about to make a 20,000 sq ft floor area building for my business and I'd like it to be beautiful and healthful!

You can make adobe by mixing about 2 parts sand to 1 part clay mixed with water, with some chopped straw added to help bind it, and use this to make beautiful adobe floors. The same mix (minus the straw) can be used for rammed earth floors. The process of doing this is not really so simple that you could expect to do it well without some prior experience or training...so I suggest that you seek this out. Both adobe and rammed earth floors are fairly durable, and can be made water and stain resistant by oiling and waxing. These floors are not as maintenance-free as concrete or tile would be.

What's the ongoing maintenance that they'll need?

We had an adobe floor throughout much of the house I built awhile ago, and the regular maintenance mainly involved giving it a light re-oiling with linseed oil once a year. Beyond that I had to periodically repair particular spots where the adobe chipped up for some reason. I did this by mixing the original powdered adobe soil with straight linseed oil to make a paste and troweling it into place.This would dry over several days into a very hard patch that was hardly visible.

I have Mex tile in my home and it sounds similar to that. Occasionally it chips and I make a mix and fill it.

Adobe is more like dried mud than low-fired tile. Tile usually has a much higher percentage of clay in it than adobe.

What about stabilizing with magnesium or Portland cement?

This is possible, and it might make it more durable; such stabilization is used with standard adobe bricks in certain situations.

I'm especially thinking of the basement floor where pallet jacks will be carrying lots of heavy stuff across the floor.

If this is the case, I would think that an adobe floor would not be your best choice. This is just the sort of treatment that can make a mess of a nice adobe floor, where people often take off their shoes to protect it.

Q: Which non-toxic sealer can be used to cover concrete?

A: There are a number of concrete sealers on the market. Which one you would choose depends upon the details of your floor. Is it an interior concrete slab? Or exterior? Is the concrete new or old? What kind of traffic will it get, and what are main protection concerns?
AFM Safecoat has a few options. The prices range depending upon the product and who you will buy them from. You may want to check out:
-Safecoat Mexeseal
-AFM Penetrating Water Stop
-AFM Safecoat Paver Seal
-SafeChoice X-158
-AFM SafeSeal

Q: I am interested in waxing an earthen floor that has had 5-6 coats of boiled linseed applied to it. What is the specific process for waxing the floor including types of wax (Carnauba and/or beeswax), ratios of wax, preparation of the wax (heating etc.), application techniques and finishing techniques.

A: To finish your earthen floor with a wax layer, make sure your oil layer is dry (fully absorbed). Then, make a paste by melting 1 part wax with 2 parts linseed oil. While the paste is still warm, rub it into your floor with a clean, lint free rag. Be careful when melting the wax and mixing it with the linseed oil. Boiled linseed oil has drying agents that are flammable, therefore, you want to be careful with the oil. Beeswax is one of the more common waxes to use. I have only used Beeswax but I understand that Carnuba wax is very hard and works well. I would suggest mixing a small amount of the wax mixture to begin with as a little goes a long way. The wax will wear off over time and you will need to re-wax to make it waterproof again. The frequency of re-waxing will be dictated by the frequency of foot traffic.

Q: We are going to rent (from friends) a house with carpet over concrete flooring. We want to get rid of the carpet but not spend much on flooring. The concrete is rough and I imagine very cold in winter. I was wondering about putting some type of earth floor onto the concrete. Can this be done? What would be the best method to use? I visited a house once that was mud and cow dung on the floor. It was lovely underfoot. I guess they sealed it with something but what kind of maintenance would this require? if you know about doing this I would love some advice.

A: (Kelly) You certainly can put a mud or adobe floor over concrete, but this will not solve the problem of cold coming through. For greater comfort you would probably need to place a layer of insulation over the concrete before applying the earthen material (unless the concrete happens to be insulated from below). I have seen this done using dense foam board of the sort that is made for direct burial. This of course would raise your floor several inches (perhaps 5 or 6 inches), and this may not be practical. There is an article about adobe floors that I wrote here.

Q: We are building our house with wood, and as the wood dries inside we have some cracks in the floor. Have you ever heard of people filling the cracks with a mixture of beeswax and sawdust?

A: (Kelly) Beeswax never really hardens into something that I would expect to be very durable for a floor. I have mixed sawdust with white carpenter's glue (which dries rather clear) to make a putty, and this has worked well. It can be sanded to blend in with the original wood nicely.

Q: We would like to make earth/clay floor for our traditional Mongolian yurt. Any advise on how it can be done will be greatly appreciated.

A: If you do not have any experience making an earth floor I would suggest purchasing a booklet on the process. Bill and Athena Steen of the Canelo Project have a booklet on earthen floors. Their web address is: www.caneloproject.com .

Some basics tips that I think are important: -Testing, testing, testing!! I always make several different large (1 yard or metre square) tests. I lay them out at the thickness you will pour the floor in. I try a different recipe for each test. When they dry I can see which tests crack, crumble, or are hard and crack-free (how I want them to be). Then I know the recipe I will use when I pour the real floor. Testing, and RECORDING your testing is one of the most important things.

-Find a good clay soil source. The better your clay soil, the more durable your floor will be. If the soil does not have enough clay content, the floor will be crumbly. If the soil is too silty, the floor may be dusty.

- I lay my floors in three stages. A base coat mix (1.5 inches thick), a secondary base coat mix (1.5 inches thick), and then a top coat (.5 inches thick). It doesn't matter too much if the base coats crack, but your really want that top coat perfect (hard, dust-free, crack-free).

Q: I live in India. I have fixed, rough, unpolished Kota stone (kind of Sandstone )in my living room. During renovation a lot of paint, cement, dirt, grime has accumulated on it and I cant find any way to clean it...mainly because it is rough. Can you advise on how I can clean the floor and keep it dust free for easy maintenance? The color is grey-green and I want the color to really show.

A: I am sorry to hear your Kota stone has been covered with paint and such. It is very difficult to remove these kinds of things from textured materials such as stone without using noxious, and toxic materials to clean them.  As I have never been to India, I do not know what kinds of materials you have at your service. The most obvious thing that comes to mind, is a lot of 'elbow grease' and a wire brush. This may be able to remove much of what is now on your stones. The bristles of the brush can get into the crevices. We have something here called "Tea Tree oil". I use it as a 'home remedy' for removing stubborn things like paint and primer. It is fairly expensive if you are using it in large quantities. Maybe you have something similar in India that is natural and will help to break down the paint etc. I do not know of any home recipes for this. There are natural products that companies sell here in America, to seal masonry and give it a shine, but they are manufactured.

Q: For thermal mass and health reasons, I'm leaning toward concrete with in-floor heating for the ground floor of our new home. What would you recommend for surface treatment that will provide an attractive look but will also be more sustainable and not off gas. I have multiple chemical sensitivity. Are the etching chemicals and coatings on the market safe?

A: (Kelly) It seems to me that you have several avenues to explore. Tiles are certainly an option, as they are durable and do not off-gas. Also you can mix oxide colorants directly into the concrete before it is poured, so that it is integral with the the floor and cannot chip or be scratched, and these are completely safe as far as I know. As for the surface treatments that are available, I am not sure how much they might off-gas. I suggest checking with the manufacturers or ask local concrete floor specialists about this.

Q: I would like to use a concrete floor in my kitchen/living room and I was wondering if you know any ecological sealants that protects it against staining and dusting?

A: I do not often work with concrete, therefore, I do not have personal experience. However, here are a few sources for you to check out:

Green Building Supply has a list of products- www.greenbuildingsupply.com

The Real Milk Paint company sells Tung oil which can be used on Concrete floors- www.realmilkpaint.com

Here is a link to a photo of a concrete floor sealed with Tung oil at the Salmon Creek Falls Environmental Center (scroll down for photo)- www.realmilkpaint.com

AFM Safecoat also has masonry sealers- www.afmsafecoat.com

Q: We are thinking of sealing furniture and floors with boiled linseed oil/mineral spirits. One site - www.naturalhandyman.com - suggests that boiled linseed oil may contain arsenic, beryllium, chromium, cadmium, nickel which may cause cancer or birth defects. What are your thoughts on this?

A: I had not heard that boiled linseed oil contained those particular ingredients. I have never picked up a can of boiled linseed oil and seen the warning label that the handyman listed on his website. This could be due to the regulations and ingredients of different brands in different states (in the United States for example).

It seems clear that the drying agents are what we are concerned about in boiled linseed oil. The agents differ brand to brand, country to country. I would suggest looking up the msds sheet on your local brand of boiled linseed oil to see the ingredients. You can do this easily on the internet. I have always recommended wearing the proper safety gear (gloves and respirator) when using products like these. And make sure to read the labels to use it safely, particularly in regards to rags and cleanup! Keep in mind even organic and natural materials warrant proper handling for safe health. For example wearing a respirator when working with straw or sand will help keep particles out of your lungs which is important on preventing lung disease. Lastly, you might want to contact a company that specializes in natural materials to find something suitable for your use. If you are in the united States, I would recommend contacting Bioshield.www.bioshieldpaint.com

Q: We have an earth floor that was laid six years ago. The top layer is clay sand and cow shit drenched in linseed oil. It is a little soft so we have put cups under some of the furniture to stop their feet sinking in. It has been a little sticky from time to time but this year it really seems to be breaking up. Every time we sit on a dining chair it sticks and pulls a little plug out of the floor. Even a rug sticks to the floor although it does not break it when it comes away. Today my partner just stood still for a while and his slippers pulled a patch of floor up with them. We have not done much maintenance just a wax mixture on some areas a couple of times. Should we perhaps have washed it more? I see some people are re-oiling every year is that what we should have done? What can we do now?

A: I do no think that your situation has been caused by lack of maintenance. I know many floors that have never had linseed oil applied after the initial oiling and some people choose not to apply wax at all.

What I am curious about is this "It has been a little sticky from time to time". This seems strange to me. Normally a floor can be a bit tacky right after the last coat of oil. This will go away swiftly with use. If the tackiness does not go away ever, it is because all excess oil that did not penetrate should have been removed. So now the question is: why does your floor get tacky off and on? It makes me wonder what is happening underneath your floor. Is it possible there is moisture wicking up from underneath? Do you know how the floor was installed? Was there a capillary break of some sort to prevent moisture from moving upward (layer of drain rock for example).

It also sounds like it is possible the recipe for the floor mix was not super strong if it easily dents. That could arise from a number of factors. That said, these floors are softer, they are not like concrete by any means which is one of their alluring features. It is always recommended to use caps or felt bottoms under the legs of furniture to prevent point loads and scratches. It sounds like you may have to re-do the top coat of your floor, and possibly more depending upon the installation method.

Q: We built our home with an earth floor, and it is very dark and beautiful. Now I am trying to lighten up the house. Can you think of a way to lighten up the floor? I was wondering about adding something, lime perhaps, to the oil and applying a new top coat. Any ideas?

A: The only thing that I can think of to lighten the floor is to poor an new topcoat using light colored materials. The problem in terms of painting something on, is getting something to bind to the oil finish on the existing floor. You might want to contact Sukita Crimmel from Claylin in Portland, Oregon since this is her specialty. She may have some other suggestions. www.claylin.com

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