Updated in Winter 2019
Testing glues and silicones was the hardest part of building my tiny house since I did this when I was highly sensitive.
But you’re going to need glues, caulks and adhesives if you are building so it’s a good idea to start testing them out. This post covers low VOC, non-toxic options that are suitable for the chemically sensitive or the health-conscious.
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Non-Toxic Wood Glues
It’s difficult to extrapolate a small jar of dry glue to a house filled with it. (In retrospect I would have tested a much larger dry sample.) I smelled them wet because I got a clearer sign of their relative effects on me. Since I have not figured out a better way to test materials, that’s what I’m working with. It is often a better idea to sniff something dry as the rate of offgassing and curing can vary greatly between chemicals.
Here were my reactions to different glues:
Gorilla Glue – I found this to be difficult when wet, but not terrible. It seemed fine to me when dry. (Easy to find at hardware stores and on Amazon.)
Elmer’s Wood Glue – Not good for me when wet, but many chemically sensitive prefer this brand (Carried at hardware stores and on Amazon)
Roo Glue – White and wood glue – Not great when wet, but not terrible. It seemed totally benign when dry. The severely sensitive should try this brand even though it’s special order. (Available in the US and it ships to Canada).
Titebond – This is a brand that is recommended for chemically sensitive folks. I had already picked Roo Glue before I got a chance to test it. I do know people that build for the chemically sensitive who use this brand. (Easy to find at hardware stores and on Amazon). I would start here since it’s inexpensive and easy to order from Amazon and find in stores.
ECOS Wood glue – ECOS makes extremely tolerable products, and while I didn’t get a chance to test this one, I would expect it to be quite good.
Hide Glue is the most natural glue option for wood. It is a strong glue with no VOCs but it is not waterproof. You can mix it yourself from beads or flakes for the most natural option, or you can buy it ready-made which does contain additives.
Which Caulks are Mildewcide Free?
I would recommend getting a non-sensitive person to put them in jars and only testing them after they have dried. Note that caulks labeled for bathrooms or mildew resistant contain a mildewcide. Currently GE I is mildewcide free, GE II contains a mildewcide and DAP makes an aquarium caulk that is free of mildewcides. Any caulk labeled aquarium safe is free of mildewcides. AFM Safecoat and Chemlink Durasil are also mildewcide free.
Top Non-Toxic Caulk Brands
All caulks have a chemical odor when wet. I tested them at 24 hours, 48 hours and one week.
AFM Safecoat Caulk – Not the best when wet, not the best at 24 hours, but the best at one week. I used this in my bathroom, you can use this around the shower and sink. It can be used around doors and windows.
It comes in white and is generally a replacement for silicone. It is polyether resin that does not contain solvents (it’s not acrylic, latex, silicone or polyurethane). It is non-shrinking. 0-VOC. It does not contain a mildewcide. 35% elongation.
GE Silicone II Clear Caulk – This may be a better choice for the exterior. It was not as good at one week as AFM or Ecobond (Ecobond now out of business). We used this on the underbelly of my house and on my windows. It is low-VOC. I find that after a couple of weeks it is fine for me. GE I is the one without mildewcide. 50% elongation.
ChemLink DuraSil – This type of silicone-replacement caulk (also polyether) is highly tolerable. This company makes great products that you can find at the Green Design Center. I have not tested this one myself but I would expect it to be up there with the most tolerable. No mildewcide. It comes in clear and white. 50% elongation.
Aquarium Caulks – I have read that aquarium caulk is the least toxic because fish are exposed to it and they can’t handle chemicals. I tested two brands, Aquarium Silicone Caulker and one called Marina from a local pet food store, they were much more expensive than brands for home use (for no reason), and they were both the worst of the worst. So bad I would not recommend testing or using these brands. One super sensitive person preferred the Aquarium caulk Aqueon to GE and Ecobond.
Chemlink also makes an elastomeric caulk for sealing concrete and masonry called NovaLink35. I haven’t tested this one, but again it’s a great brand.
Caulking Materials – What Caulks are Made of:
Polyurethane caulks – usually contain isocyanate. Not as safe.
Acrylic Latex caulk – they have mildewcides in them. Painters caulk are usually acrylic latex and are sandable and paintable.
Silicone – While silicone itself is not toxic, chemicals are added to keep caulking in liquid form are. These chemicals offgas at different rates until the product is fully cured. For silicone caulk, look for 100% silicone, but each brand has different additives that affect people differently and offgas at different rates. 100% silicone is not really 100% silicone, but the chemical additives are not listed. Solvents used to keep silicone in liquid form are listed here.
Polyether – specialty silicone replacement materials are often polyether.
Construction adhesives are used for subfloors, to install doors (glue down threshold), exterior brickwork, under countertops, etc.
The best adhesive I have ever tested is AFM Almighty Adhesive. I had absolutely no problem and no reaction to smelling it while it was wet. This was a pleasant surprise after all the other glues and silicones. It is a highly tolerable very low chemical multipurpose adhesive (make sure it’s right for your application). Insider tip, this is the same formula as Build Secure by Chemlink.
I used Almighty this to install my shower, on subfloors, countertops and really anywhere this can be used since it’s the healthiest adhesive I have found. It has many applications, I always use this one if it works for the project.
Chemlink Wallsecure is a good adhesive for subfloors (they say less toxic than Liquid Nails).
Liquid Nails subfloor adhesive is also well tolerated by many.
Ecotite is another good brand liked by the chemically sensitive. Their ET 5500 is an adhesive that works on a number of surfaces. The 9500 is used for windows, doors and some kitchen applications. These links are to a Canadian store but you can find this product in the US as well.
Corinne Segura is a Building Biologist with 6 years of experience helping others create healthy homes.
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