A Guide to Non-Toxic Sealers, Stains, and Varnishes - My Chemical-Free House (2024)

This post is my overview post on sealers.

I’m starting with oil sealers for wood because these are the only totally pure and natural options. Natural waxes are sometimes used with oil finishes and so those follow.

But what about if you want to add a stain to the wood? Onto looking at both non-toxic water-based wood stains and natural oil stain finishes.

Then an overview of clear zero-VOC water-based wood varnishes – some of these are durable enough for floors and others are only for furniture or walls.

Cabinet paints are next. A notoriously difficult surface that needs a smooth and durable coating without added toxins or VOCs.

Another way of looking at sealers is not just as a protector against water and stains but to seal in an offending chemical or odor. An overview of those sealers is included.

Next are exterior sealants, a category that is almost always higher in VOCs than their interior counterparts, these are the healthier options.

Lastly, an overview of stone and concrete sealers and where you can use each of the non-toxic brands in this category.

This article contains affiliate links. Upon purchase, I earn a small commission at no extra cost to you.

1. Natural Non-Toxic Wood Sealers

i. Natural Oil Wood Finishes

Linseed, tung, refined hemp, soy, and walnut oil areall-natural oils that on their own can be used to seal and protect wood. They are called drying oils.

Drying oils penetrate, harden, and preserve wood – providing a long-lasting finish that does not turn rancid.

Coconut oilif refined can be used on wood and won’t go rancid. But it’s not a drying oil, meaning it won’t polymerize and form a durable coating (source). I wouldn’t recommend using olive or other (non-drying) oils because those can go rancid on wood.

Linseed and Tung Oil

Linseed Oiland Tung Oilare the traditional natural finishing oils for wood. These are the two toughest natural oil finishes, with tung oil being the toughest.

Both are great for wood floors. (Be sure to see my post on oil finishes for floors if you want to know which solvents are needed and how detailed the application is).

Although they are natural, legally no-VOC, and technically non-toxic, they do offgas aldehydes (and other compounds), which can be bothersome for the chemically sensitive.

I review tung and linseed in detail in their own dedicated post. That includes a look at Rubio Monocoatand Odies Oil.

I look at additives including possible metals, chemicals added, as well as which compounds they offgas, and when they fully cure.

Linseed and/or tung are often labeled as “teak oil” or “Danish oil”, though this is a general term that can mean either it’s pure or mixed with additives, as I go over in the post on these oils.

Hemp Oil Finish

Hemp Oilis often my top choice for an all-natural drying oil for wood (but not floors) due to how mild and safe the odor is.

I used hemp oil on all the interior wood in my chemical-free tiny home.

It does have a light aroma, which I would consider pleasant. I would test for your own sensitivities (and allergies) by buying a small amount first.

Hemp oil is the only ingredient in the Milk PaintCompany and the Homestead Housebrands.

I used the Milk Paint brand and was happy with it. If you order it directly through their website you can get 10% off with code mychemicalfreehouse. You can also buy it on Amazon.

It’s not the most durable of the wood finishes compared to linseed and tung oil and that’s why it’s not used on floors. Tung oil is the most durable, followed by linseed oil. If you do well with those oils, they are better suited for hardwood floors.

Make sure it’srefined hemp oil(made for a wood finish) as opposed to the edible oil from the grocery store.

This finish is certainly one of the safest and healthiest options for wooden toys, butcher block countertops, and other food-contact surfaces.

Walnut Oil

Walnut oil, another drying oil, is used on surfaces like concrete countertops, raw slate, non-glossy marble, granite, soapstone, sandstone, and onyx.

I tested the Milk Paint walnut oil (pictured on the tray) and the odor is very mild, even lighter than hemp. I was extremely happy with its performance on stones.

I go through sealing various stone types more in the countertop post.

You certainly can use it on wood, but it’s not as durable as the above oils, so it’s best suited to cutting boards, toys, bookshelves, and decor items.

You can buy Milk Paint walnut oil on Amazon or on their website. You can use code mychemicalfreehouse for 10% off on the website.

Rosewood Oil

Another oil to check out isPenofin Verde which is Brazilian rosewood oil mixed with other natural oils. They use “vegetable ester solvents” and I would expect a solvent odor and some offgassing here.

Oils need to be reapplied to wood every few years or more in high-traffic areas.

For information on using natural drying oils on stones (which ones work to protect stones and which ones can discolor them), see my post where I test them all.

ii. Natural Wax Wood Sealers

Wood can then be finished with a beeswax or carnauba wax polish for extra durability. Beeswax takes 30 days to fully dry.

Walnut oil with carnauba wax (pictured) is my preferred type. It works great and has no solvent. I have used this brand on stone and wood.

I also used beeswax on my window sills over the hemp oil to provide a more water-resistant finish and I was really happy with it. It also works well on counters, cutting boards, and toys.

ThisBeeswax/Carnauba Polishworks well but does have mineral spirits in it. Mineral spirits do evaporate quite quickly and leave the product once cured. I haven’t found odorless mineral spirits to be a very toxic ingredient but it’s not for everyone (it’s not totally non-toxic like the walnut oil mix above).

Hemp and beeswax mixed together make a great food-grade finish for cutting boards and other items. I like Fusion brand which is 100% hemp and beeswax with no additives.

Wax usually needs to be re-applied every year.

Natural Shellac Resin

Shellac is a resin and one of my top picks for many different purposes.

Shellac, in the purest version, is just the natural flakes of the resin produced by a beetle, and alcohol.

You can purchase flakes from Amazon.

Shellac can be used on many indoor surfaces, including floors, toys, and furniture.

Natural, de-waxed shellac, would be the purest choice for most projects. It does come in a synthetic formula as well, so be sure to check which type it is. Regular (waxed) would be used for some applications.

If you want to buy it ready-made, Zinsser makes one they claim is only shellac and alcohol. (If it’s not available on Amazon, try Walmart)

I discuss this more in the posts on sealing in toxins since this finish is great at sealing in offgassing and odors.

Oils for Earthen Floor Finishes

If you don’t have oxblood on hand, no problem, you can seal your earthen floor with any of the hardening oils we talked about under wood finishes. Linseed is typically used.

Beeswax can also be used in the final coat for extra protection if desired.

iii. Natural Non-Toxic Wood Stains

Natural Oil Wood Stains

Each oil in the section above will tint the wood to some degree, so you should test for the look you want to achieve – you might find thatyou don’t need a stain at all.

Or you may need a stain to lighten it!

If you do want a stain, I prefer the oil and stain in one options:

1. Rubio Monocoat

Rubio is a low-odor modified linseed oil finish with many color options. We don’t know a lot about what’s in it other than (modified) linseed and wax. It’s significantly lower odor than pure linseed. It does have a drier, the Part B, which smells like a solvent. You can use it without Part B. I have used it and review it in more detail in this post.

Out of the oil finishes this is the easiest to apply because you only need one coat.

It comes in 40 different colors including lightening shades like greys and whites. All of the colors are Toy Safe EN-17.

They claim zero VOC, though the MSDS does indicate some VOCs.

I really like this brand for both low odor, performance, and color options.

2. Tried and True

Tried and True has a pure polymerized linseed and pigment mix with nothing else added. This is the most natural option, with no solvents or additives.

Tried and True premixed oil and pigment stains went on beautifully. I tested the Java color on oak.

It comes in 5 darkening shades. This is my top choice if you want something pure and don’t need many color options. (Note that on floors, they recommend the final coats are done with the mix that has pine oil).

Legally linseed is zero-VOC, but it does give off natural volatile compounds. I do a deep review of linseed and tung oil in a dedicated post.

4. Osmo

A well-known worldwide brand, OSMO stains alone are low odor but they are meant to be used with the top coat of Polyox Oil.

Polyox oil contains sunflower, soya, and thistle oil, with waxes, including paraffin, plus de-aromatized white spirits, siccatives, and polysiloxanes. They declare all of their ingredients.

The Polyox oil had a very noticeable solvent odor for me, the majority of that odor did flash off somewhat quickly but the general odor did take more time than I expected to go down. I did not consider this low enough in toxins for me to use when I was sensitive.

I did really like the stain colors though. The Wood Wax comes in bright colors (along with the usual wood stain colors and greys and white) which would be fun for art and toys.

The Oil Stain, which is for floors, comes in 10 colors including lightning shades.

They claim very low VOCs.

I would put WOCA finishes in this same category of solvent-enhanced natural oil-based finishes. (I personally would not use WOCA or OSMO).

Water-Based Non-Toxic Wood Stains

The truly non-toxic water-based wood stains are more difficult to apply than the oil-based ones. A water-based stain that does not contain ammonia is the most finicky type of stain to work with.

If a water-based stain advertises that they don’t raise the grain then it can be assumed to contain ammonia.

1. ECOS Paints stains

ECOS makes the most tolerable finishes in my view. The stains come in 14 different shades (one grey one) and a clear coat of varnish follows.

This was highly tolerable for me when I was at my most sensitive. They also have tinted varnishes.

All of their ingredients are fully declared. These are acrylic-based, which is usually more tolerable than polyurethane, though less durable, and it works for most chemically sensitive folks. If you just use the stain then you can use your own topcoat, just make sure it’s compatible.

2. AFM Durotone

A recently improved formula from a popular brand for the chemically sensitive.

It comes in 11 colors including one lightening shade.

A top coat is required – either water-based or oil.

If you are staining pine, that wood is notoriously tricky, see my dedicated post on sealers for pine.

iv. Clear Water-Based Wood Sealers

1. ECOSvarnishes, which are acrylic-based, are super low toxin. In my experience, they are not as durable as the polyurethane alternatives.

I used ECOS sealer on the wood in my kitchen and I was very happy with it. I have not had problems with water marks, but I would not use this on the floors. I would use this on items that don’t require a super durable finish, like wood paneling or bookshelves.

I find this to be a very tolerable brand that I was able to apply myself at a time when I was very chemically sensitive. My post where I test and compare all the water-based finishes is here.

2. AFM Polyuresealis liked by many. It is a very tolerable formula by a high-quality brand. This brand is a durable low-toxin polyurethane finish for hardwood floors.

3. Vermont Natural Coatings PolyWhey was my top choice for a durable coating that holds up well on floors and was very low odor. It has the best combo of durability and low odor that I have found.

4. Other very low-odor polyurethanes and acrylics: BioShield Aqua Resin, Earthpaint Aqualine and Easy Safe 1K, and Vermeisteer. I compare them all in a dedicated post.

I tested and compared all of the clear wood finishes – the full post is here.

5. Danish Soap finish. An unusual non-toxic way to finish floors is a Danish process using soap as the finish. You can either use just soap, or soap and lye. Lye is quite toxic while it’s reacting, but it’s safe when it dissipates.

When used in the making of soap the lye reacts with other components and in the end, you just have a safe soap product.

PS. If you are looking for a clear sealant to seal paint (whether to make it glossier, more durable to wear and tear, or more waterproof) this post on paint sealers covers that topic.

v. Non-Toxic Kitchen Cabinet Finishes

Clear Finish for Cabinets:

• AFM Acrylacq is a clear alternative to conventional lacquer. It is acrylic and siloxane. You can get a matte look by using 2 coats of gloss finished with a coat of matte. Or you can use the gloss or satin. AFM is my top choice in this category. VOC 93 g/l.

• AFM Poly BP This is a polyurethane finish (with a little bit of acrylic). This is another durable finish for cabinets. VOC 93 g/l. You can also use their exterior version of polyurethane called EXT.

• EarthPaint Easy Safe 1korNanoTech Clear.

• Vermont Natural Coatings PolyWhey Floor Finish can be used on cabinets. These are polyurethanes that are partially naturally derived. I like this brand because it’s a great mix of durability and low odor.

Water-based cabinet finishes are not as durable as lacquer finishes. However, lacquer needs to be professionally applied and is toxic until fully cured. You may find some factory finishes that don’t have offgassing because they have been UV-cured which speeds up the curing.

My detailed testing of these water-based brands can be found here.

Natural Oil Finish for Cabinets:

• Rubio Monocoat Oil Plus for furniture comes in a lot of cool colors. It is easy to touch up and has been reported to work well on cabinets. If you don’t mind the natural linseed oil and some unknowns with the formula, I really like the quality of this finish. I would be tempted myself to use this on cabinets because this finish is so easy to apply and to retouch (something that other non-toxic cabinet finishes cannot claim). Also, oil-based finishes tend to outperform water-based finishes.

Paints that are suitable for cabinets are found here.

vi. Sealing in Toxins

Sealing in Fungicides

If you are buying new wood-framed windows, the wood will likely have been treated with fungicides and should be sealed with AFM Safe Seal,AFMTransitional Primer, or Zinsser Shellac.

This version of shellac from Zinsser claims that the only ingredients are shellac and alcohol. That’s one you can find at Walmart as well as Amazon. You can also mix the flakes yourself with Everclear alcohol.

Sealing in Formaldehyde

AFM Safeseal is used to seal in formaldehyde in engineered wood products.

You can also use shellac which is one of the best sealers to seal in odors and VOCs, including formaldehyde. I have tested these side by side on formaldehyde offgassing and they both performed very well.

Safeseal is made with acrylic polymers and is extremely low odor.

Sealing in Wood Odor/Terpenes

Clear-Coat Options

Shellac is the best sealer for sealing in the odor of wood. Depending on where the wood is, you may need to go over that with another sealer that can take water better.

That shellac is dewaxed, it’s thinner, but it’s easier to paint or coat over. You can go over dewaxed shellac with AFM Acrylacq.

Acrylacq can also be used on its own. The vendors estimate that it seals in the odor on its own by about 80-90%.

Painted Options

All acrylic paints seal wood odor to some degree.

The other option is to use shellac followed by paint. I like Bullseye (waxed) shellac followed by Annie Sloan Chalk Paint or Rustoleum Chalked.

For more on this topic, see my posts on Sealing in New Offgassing and Sealing in Fragrance, Smoke, and Related Chemicals.

vii. Exterior Wood Sealers

Natural Oils

To protect exterior wood like decks, siding, fences, and outdoor furniture against the elements, you could use more potent oils than you might use inside – oils based on linseed oil or tung oil are durable.

1. Rubio Monocoat Exterior Oil, like their interior oil, this is linseed oil-based, but they don’t declare all of the ingredients.
2. AFM Penetrating Oil is made from polymerized linseed oil, organic flaxseed oil, isoaliphate, modified soybean oil, hemp oil, carboxylate metallic salts of calcium, manganese & zirconium.
3. I like Milk Paint Company Outdoor Defense Oil. It is made of tung oil, pine oil, and zinc. If you do well with tung and pine oil, this could work for you. It’s very durable, and while the application is a bit tedious it’s going to be the most durable natural oil for fences, decks, and outdoor furniture.

Water-Based Sealants

1. Vermont Natural Coatings Exterior PolyWhey is the best of the water-based synthetic coatings and it can hold up as well on decks, fences, and other outdoor wood.
2. AFM has a new exterior clear sealercalled Polyureseal EXT which is an acrylic/polyurethane. It can be used on outdoor furniture. It can be applied to raw wood or wood stained with Safecoat wood stains, and concrete or previously painted surfaces that are properly prepared.

For more options and details on these sealants see my dedicated post on deck, fence, and outdoor furniture stains and sealers.

2. Non-Toxic Tile, Concrete & Stone Sealers

i. Stone, Concrete, and Brick Sealers

For a detailed look at concrete floor finishes, see this dedicated post.

1. AFM Mexesealis a surface coating for masonry/stone. It is for unpolished marble, limestone, granite, sandstone, slate, fireclay (brick, tile, terra cotta, pavers), and concrete. Mostly for honed stones – though it can work on some polished stone (you would have to test it). Good for slate floors, and concrete floors. In sum, use on porous interior tile or masonry surfaces where oil and water repellency are desired. Not for use outside.You can use it on shower walls but not shower floors. The product is polyurethane and acrylic. Very low VOC.

2. ECOS sealer/stainis for concrete, masonry, brickwork, and plaster. They make a solid color concrete sealer and semi-transparent concrete sealer. These are acrylic coatings with a little bit of silicone in there.

3. ECOS clear sealeris acrylic, just like the stains with pigment. You can use it on concrete floors.

4. AFM Penetrating Water Stop(zero-VOC) for porous, mineral-containing surfaces such as brick, pavers, concrete block, other cementitious materials, stone, and stucco.I used it on my concrete bathroom tiles and on the clay plaster in my kitchen. The only components listed on the SDS are silicone and lye. This product does not create a film on top of the surface, it is more like a densifier.

6. AFM Watershield is a clear, penetrating sealer that repels water, grease, and oils. For use on porous surfaces such as concrete, stucco, brick, and stone. This can be used over American Clay Plaster. This can also be used outdoors on vertical wood surfaces e.g. under eaves that are raw wood or those stained with water-based stains such as AFM Durotone. Not for use on decks or horizontal fence railing. This is an acrylic sealant.

7. Milk Paint Soapstone Sealeris walnut oil and carnauba wax. It works well on interior stone countertops and stone tiles made of soapstone, concrete, raw slate, honed marble, granite, sandstone, and onyx. You can buy this from the Milk Paint store and Amazon. I have used this sealer on many stone surfaces and I have been really happy with it. It’s all-natural and low odor. It needs some time to cure, but all natural oils do.

8. SimpleCoat. If your countertops or floor tiles are a white or cool-toned light-colored stone, an oil sealer will not work as it will yellow it too much. SimpleCoat is one of the only non-PFAS sealers for light stones.

9. Hemp Oil is also a drying oil, and like walnut oil, it does work on most stone and concrete (as well as wood). It can change the color of some stones, so test it first. It passed my tests, but it can yellow or green just a little, depending on the base color of the stone. It’s for interior use.

10. Acri-soy is a concrete sealer that can also be used on stone as well. This is an acrylic made from natural sources. This page explains what that means. This is my top pick for a concrete floor finish (more in my post on concrete floors).

11. Tung oil also makes a good finish for concrete and many stones. It can be used on concrete floors and birdbaths as well. It is often preferable to other oils in outdoor conditions. (I review the offgassing odors of tung and linseed in a dedicated post). Tung oil forms a very durable coating on high-wear surfaces.

For a detailed look at my testing of natural sealers on stone surfaces see my dedicated post.

ii. Concrete-Based Grout Sealer

For sealing grout there are a number of good options,I discuss grout sealer options in my post on grout and thin set.

Corinne Seguraholds certificates in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes.

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