Updated Winter 2021
Testing wood glues, construction adhesives and silicone caulks was the hardest part of building my 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!
You’re going to need them for repairs and renovations too. I would suggest knowing which ones work for you before that urgent repair is needed.
This post covers low VOC, low odor, non-toxic options that are suitable for chemically sensitive or health-conscious folks.
This post contains affiliate links to products I recommend. Upon purchase, I earn a small commission at no extra cost to you.
Non-Toxic Wood Glues
I compared the odor level of these glues when wet. It is usually a better idea to sniff something dry/cured since there can be a dramatic difference between how tolerable something is wet and when cured.
Testing when it’s cured is the most important test in most cases.
Top Non-Toxic Wood Glue Brands:
Many chemically sensitive prefer this brand.
This is a PVA based glue, with a mild acetic odor until it’s cured. PVA glues are some of the most benign. Though at my worst I did not do well with this when it was wet.
Carried at hardware stores and on Amazon.
ECOS makes extremely low-toxic products, and while I didn’t get a chance to test this one, I would expect it to be good.
The ingredients are acrylic dispersion, thickeners made of cellulose and polymers (plastics), and unlisted dispersing aids.
3. Roo Glue
Roo Glue makes white glue and wood glue. It seemed totally benign when dry. It was one of my top picks when I was extremely sensitive to chemicals.
The severely sensitive might want to try this brand even though it’s special order. Otherwise, stick to Elmer’s or Titebond wood glue.
This is a PVA glue.
Available in the US and it ships to Canada from their website.
This is a brand that is often recommended for chemically sensitive folks as a safe adhesive. I had already picked Roo Glue for my chemical-free house before I got a chance to test it.
My sofa was later made with this and it worked out well for me, though I received it after it had cured.
Out of the Titebonds, Titebond III technically has the lowest VOC level of the 3 main types of this brand’s wood glues. It comes in at 5.6 g/l VOC.
These are PVA glues.
I would start here with the testing, since it’s inexpensive and easy to order from Amazon and find in stores.
5. Hide Glue
Hide Gue is the most natural glue option for wood. It’s made from animal protein of the collagen from skins, bones, tendons, and other tissue.
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, but those do contain some additives.
The Titebond brand lists ammonium thiocyanate.
For the most natural non-toxic wood glue possible, this is the top choice. If you don’t need a waterproof adhesive and are not vegan, this is the healthiest option.
6. Gorilla Glue
I found this to be difficult when wet, but not terrible. It seemed fine to me when dry.
This is a polyurethane glue that will offgas isocyanates until it’s cured. Isocyanates are potential human carcinogens and known to cause cancer in animals. Like many products, if it comes to you cured it may be perfectly safe.
It’s easy to find at hardware stores and on Amazon.
Non-Toxic, Low-VOC Caulks and Sealants
Which Caulks are Mildewcide Free?
Note that caulks labeled for bathrooms or as mildew resistant contain a mildewcide. Currently GE I is mildewcide free, GE II contains a mildewcide. Any caulk labeled aquarium safe is free of mildewcides, including DAp Aquarium caulk and others listed below. AFM Safecoat and Chemlink Durasil are also mildewcide free.
Top Non-Toxic Caulking/Sealant Brands
All caulks have a chemical odor when wet. I tested them at 24 hours, 48 hours, one week and two weeks.
If you are chemically sensitive I would recommend having a non-sensitive person put a test amount into a jar and to sniff it when it’s cured.
AFM Caulk is one of the top choices and is one of two main caulks to have on hand in every build and renovation.
I used this in my bathroom, you can use this around the shower and sink. It can be used around doors and windows.
It’s used indoors anywhere where it interfaces with a paintable surface and is the non-toxic replacement for acrylic latex caulk.
My testing: Not the best when wet, not the best at 24 hours, but the best at one week.
Where to use AFM Caulk:
It can be used inside and outside. Around windows, cracks, tub and shower enclosures, backsplash, siding, walls and wood (like sealing molding) and general maintenance. It does not hold up as long in the bathroom as silicone with a mildewcide.
It is polyether resin (90-95%) with amino silane (1-3%) that does not contain solvents (it’s not acrylic, latex, silicone or polyurethane). It is non-shrinking. zero-VOC once cured.
You have to special order this one from Green Design Center.
Mildewcide: none. Elongation: 35%. Color: white. Paintable: yes
Alternative: ChemLink NovaLink 35 is a similar elastomeric silane modified polyether but comes in different colors, if that is needed. PSI of 145. 3M marine Adhesive Sealant 4000 also seems very similar to me (polyether 15-40%, white pigments 35-70%, plasticizer 10-20%, silane 1%), PSI 220-240 and is paintable.
GE 1 and 2 can be a better choice for some applications. This one is easy to get from the hardware store or Amazon, so if you need something fast this might be your top choice. Though I would suggest planning ahead of time to purchase better options.
My testing: It was not as good at one week as AFM or Ecobond (Ecobond is now out of business). I find that after a couple of weeks it is essentially odor-free (to me).
Testing again in 2020, most sensitive people would not pick up any offgassing at one week (it’s there, but extremely subtle). At two weeks I find this odorless, but when I was at my most extreme I could still pick up something very subtle at two weeks. Thicker amounts take longer to offgas.
Offgassing: Most of the caulks (at least all the silicone and polyethers) would be suitable for the chemically sensitive at 2 weeks. Only most extremely sensitive may still pick up some offgassing even at that time.
Where to use GE 100% silicone: Windows, doors, siding, trim, molding, baseboards, vents, around wires/pipes, in the bathroom, under countertops, and more.
We used this on the underbelly of my house and on my windows. It is low-VOC.
Mildewcide: GE 1 is mildewcide-free. Elongation: 50%. Color: Clear. Paintable: No.
Alternative: If GE Silicone doesn’t work for you, you may want to try DAP, their aquarium calk is mildewcide free, Dow Corning 100% Silicone, or Durasil below.
This is a neutral cure silicone that is a safer version of 100% silicone. This is one of two brands to have on hand (the other is AFM Safecoat Caulk). This one for interior and exterior non-paintable applications and AFM for paintable applications.
You can find it at the Green Design Center.
Mildewcide: No. Elongation: 50%. Color: Clear and White.
4. Silicone Aquarium Caulks
I read that aquarium caulk is the least toxic because fish are exposed to it and they can’t handle chemicals (especially biocides). But it turns out fish are a little different than people.
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 apparent reason), and they were both the worst of the worst to me.
So strong in odor I would not recommend testing or using these brands if you are chemically sensitive.
Marine caulking is not the same as aquarium caulk (it’s for marine applications, not fish tanks). I tested GE Marine Silicone Sealer. It had that same pungent odor though, like vinegar times a million.
It did, however, offgas quite rapidly. After one week it was at the same point as GE 100% Silicone, and at two weeks it was just as good (virtually odorless).
5. Chemlink Novalink35
Chemlink makes an elastomeric caulk for sealing concrete and masonry called NovaLink35.
I haven’t tested this one, but it’s a great brand and many chemically sensitive folks do well with it.
Caulking Materials – What Caulks are Made of?
Polyurethane caulks – Usually contain isocyanate. This type smells strongly like typical fresh paint, and takes quite a long time to offgas. They can be made without solvents. If they do contain solvents it would typically be mineral oil, toluene or xylene. It’s not used as widely as the others. I tried Loctite PL S40.
Acrylic Latex caulk – They have the mildewcide octhilinone or carbendazim in them as well as a benzoate plasticizer (which has largely replaced phthalates) and naphtha (source). They are often water based but still could contain mineral spirits, mineral oil, and propylene glycol (source). Painters caulk are usually acrylic latex and are sandable and paintable.
I tried DAP Dynoflex 230 latex caulk and DAP Alex Plus, an acrylic latex with some silicone. At one week they both had more offgassing than the silicones, though they had different chemicals offgassing. At two weeks Alex was still clearly offgassing (at three weeks I could still pick up the odor, at 5 weeks it was very mild), and Dynoflex was close to done at two weeks.
Silicone – While silicone itself is not toxic, the chemicals added to keep caulking in liquid form are. For silicone caulk, look for 100% silicone. There are different types listed below that offgas different chemicals. Once they are cured, you may find them to be essentially the same.
The chemical additives in “100% silicone” are not usually listed. Silicone doesn’t usually have a solvent but some have traces of benzene and toluene (source). Plasticizers are typically added. The biocide, if it has one, is likely to be phenoxarsine oxide, according to Pharos.
Acoustical Caulk – this non-hardening sealant prevents sound leakage. They are mostly water-based acrylic. They are about 20% ethenylbenzene. In smaller amounts, they typically contain plasticizers, naphtha (as the solvent), ethylene glycol, and formaldehyde.
Solvents common in caulking (of all types) include acetone, methyl ethyl acetone, toluene, xylene, and naphtha (Source).
Types of silicone caulk and what chemicals they offgas:
1. Typical silicone caulking is acetoxy silicone and it offgasses acetic acid. On the SDS you will see “odor: acetic acid”.
2. The less common type, labeled “neutral cure silicone”, does not give off acetic acid, but instead offgasses alcohols, methyl ethyl ketoxime or acetone. (source)
3. Aquarium caulk is usually acetoxy silicone without mildewcide. It might be labeled aquarium caulk or you can just get GE 1 if you are avoiding mildewcide, which will be less expensive.
4. Paintable silicone caulk is a mix of silicone and acrylic latex.
Polyether – specialty silicone replacement caulks are often polyether. My top pick is AFM Caulk.
Construction adhesives are used for subfloors, to install doors (glue down threshold), to build stairs, exterior brickwork, under countertops, and more.
Non-Toxic, Low VOC Construction Adhesives
Almighty is the best adhesive I have ever tested. 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 odor, multipurpose adhesive (make sure it’s right for your application). The PSI is 500.
It is a polyether (30-80%) and nepheline syenite (30-60%) adhesive, with 1-5% amino silane.
I used Almighty to install my shower, on subfloors, and my countertops. I would use this anywhere and everywhere this can be used since it’s the healthiest adhesive I have found.
Insider tip, this is the same formula as Build Secure by Chemlink.
Wall Secure is made for bonding drywall, gypsum, landscape blocks, capstones, stone, foam, fiberglass, FRP panels, and ceiling systems.
I haven’t tested this one but this brand makes great low toxin adhesives.
3. Ecotite ET 5500 and 9500
This is another good brand that is well-liked by the chemically sensitive.
Their ET 5500 is an adhesive that works on multiple surfaces: PVC, concrete, glass, aluminum, painted surfaces, wood plywood, marble, metal, and more.
At about one week most would find this odorless. At two weeks it seemed totally offgassed. I was very happy with this one.
The 9500 is used for windows, doors, trim and some kitchen applications. At three weeks it’s still not odorless/offgassed. I’m not as happy with this one as it did not stop offgassing by three weeks.
The bottles say odorless, but the point in time that it is odorless depends on the conditions (curing rate) and how sensitive your sense of smell is.
Right off the bat, the 5500 is significantly milder, and lower odor than conventional adhesives.
Corinne Segura is a Building Biologist Practitioner with 6 years of experience helping folks create healthy homes.
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