This a deep dive into the best mineral paints: chalk paint, lime paint and clay paint, to see which ones had the least amount of toxic additives and if any of them are really pure.
I test and compare all the brands available in North America. These are the least toxic paints that can go on interior walls, and the most natural paints.
What I found here was a lot of marketing greenwashing, as well as some interesting new paints that I had not tried before. I had to do a lot of wading through the nitty-gritty ingredients here to get to these recommendations!
This post is not sponsored by any of the mineral paint companies. The post includes Amazon affiliate links. I earn a small commission upon purchase at no extra cost to you.
I only found four mineral-based paints in North America that fit my criteria. Though as I investigated this, it became more and more unclear what should be defined as a mineral-based paint. They all have polymers!
I talk about some others that didn’t make the cut at the end.
Reasons for considering mineral-based paint:
- More natural, non-toxic, mineral-based paints might be more suitable for the chemically sensitive and others avoiding toxins. It may even be safe for you to apply them yourself.
- These paints are breathable, which is specified in many mold preventative wall assemblies (for example in passive house design).
- They give a natural look and feel to a room.
1. RomaBio EcoDomus Mineral Paint Review
RomaBio is a lime-based paint. It’s also a silicate paint that has another non-acrylic polymer in it (i.e. it might not be a pure silicate paint). The silicate paints are very safe, and in this formula, they help create a paint that has a really durable, washable surface that is still breathable.
Silicate paints are the type of paint that can technically be called mineral paints, but because of the unknown polymer in here, I’m not sure that this is a true silicate/mineral paint.
What I found out from digging into the ingredients and smelling it for myself, is that this one is actually (it seems to me), the most like conventional paint in odor level.
Although it is a breathable paint (95% breathable), which is specified for many builds, it did have that classic paint smell when wet (to my nose and to my estimation).
It’s not the same type of paint as ECOs or other 0-VOC paints, but the EVA ingredient and possibly the unlisted polymer are contributing to that odor that is associated with “new paint smell”.
What are the Additives in RomaBio Paint?
Their Interior paint is called EcoDomus (this is different from their exterior lime washes).
The ingredients for the white EcoDomus paint are:
Water, calcium carbonate (limestone), titanium dioxide (a metal mineral that makes things white, including food), ethylene vinyl acetate polymer (EVA) (a polymer that is common in paint and has that typical paint odor), undisclosed polymer, potassium polysilicate (liquid glass, very safe – this is the silicate part), talc, plus 13 undisclosed ingredients.
What are the undisclosed ingredients:
I’m not sure what that second polymer is, but here is a list of typical polymers used in silicate paints: styrene-butadiene, polystyrene, neoprene, polyvinyl chloride, polyvinyl acetate, acrylonitrile copolymers, acrylic polymers and copolymers (source).
Other typical additives in silicate paints include surfactants, small amounts of solvents, thickeners (like cellulose), stabilizers, modifiers. This also contains a preservative.
They also list their ingredients as follows: containing inert binders (4 – 18% depending on the product. They claim potassium silicate is the primary binder, but it also has EVA and an undisclosed polymer), natural thickeners (might very likely be a cellulose) and earth oxide pigments.
Does RomaBio Contain Toxins/Toxic Additives?
The VOCs in RomaBio EcoDomus
The paint is listed as 0 VOC, with no exempt VOCs. They do disclose detailed testing of the VOCs which reveal:
- Butanol 2.2 micrograms/m3
- 2-methyl-4-isothiazolin-3-on 5.5 micrograms/m3 (this is a preservative)
- Formaldehyde <2 micrograms/m3 (extremely low but there are aldehyde donors in here)
- Acetaldehyde <2 micrograms/m3
They state it does not contain: propylene glycol, polyethylene glycol (PEG), formaldehyde (though it has a small amount of formaldehyde/aldehyde donors based on the VOCs) or alkylphenol ethoxylates. They claim no toxic biocides/mildewcides/no toxic preservatives (but it does contain 2-methyl-4-isothiazolin aka Methylisothiazolinone which is a biocide and is not benign), no acrylic resins (though it does contain EVA and an unknown polymer), and no toxic binders.
What I Like About RomaBio (Pros):
- The Matte does not require a primer on new drywall.
- Matte is 87% natural.
- There is a fair amount of disclosure on what’s in it and a lot of disclosure on the final VOCs.
- One of the only breathable (high perm rating listed), and washable paints. Most regular 0 VOC paints like ECOS, Ben Moore do not have a high perm rating.
- The only washable flat (matte) sheen mineral paint I found that does not require a sealer to be washable.
- Durable, washable and not easily stained by oil, food (ketchup mustard etc).
- High quality – expect the quality and ease of application of regular paint. You do not have to do a sample board due to unusual application techniques/tools.
- You can use it in the bathroom and kitchen. It is mold resistant and can take splatter.
What I Don’t Like About RomaBio (Cons):
- It doesn’t have that much lower odor than regular 0 VOC paints like ECOs. It’s not clear that odor and VOC-wise, it’s better than ECOs or other 0 VOC paints (it might even be worse for some folks).
- It might be harder to tolerate than other mineral paints listed here for many folks with chemical sensitivities. Possibly due to variations in which polymer is tolerable for different folks).
- Many undisclosed ingredients.
Application Tips for RomaBio EcoDomus
EcoDomus can be applied with a brush, roller, or spray like any traditional paint. This was the most like conventional 0 VOC paint and it was the easiest one to choose the right roller for. Painters should have no problem applying it.
When applying it to the wall it is easiest to use a roller (not a brush). For silicate paints you can use polyester rollers.
I found this was easy to apply with a brush and roller, even for a beginner painter. It had the ease of application of a regular 0 VOC paint. I used a medium pile roller and it worked just fine. A short nap roller on drywall would be smoother. Wooster is a good one.
You don’t need a sealer on this one. Matte is two coats, satin and eggshell are primer plus two coats.
How Does RomaBio EcoDomus Hold Up?
You need to wait 14 days for a full cure to start scrubbing it.
I put it to the test with mustard (for the staining) and mayo (for the oil). The mayo was no problem to wipe off, both off the matte and satin.
The mustard stained both of them. It did not come off with a soft sponge with soap and water. It did come off with the Magic Eraser, though you can tell on the grey color that the Eraser pulled up a little paint. It’s not obvious on the board.
They say you can clean it with mild dish soap or other mild cleaner with a soft rag or soft sponge.
2. Bioshield Clay Paint Review
In terms of the most non-toxic of the mineral-based paints I found in North America, BioShield Clay Paint is the winner.
It has a high percentage of natural ingredients, the least amount of concerning additives and the lowest odor.
I found the odor of it even straight out of the bottle to be mild and nonoffensive. Depending on your level of sensitivity, this may smell slightly like polymers or it might smell totally benign to you.
Like every other paint that can go on new drywall, it does have a binder/polymer in it. The polymer is PVA. It does polymerize so it’s not technically classified as “a mineral paint”.
It can go over new drywall that has a skim coat with no primer. It can also go over previously painted walls if they are not glossy without a primer.
Whether you can put it over new drywall that is taped and mudded at the seams depends on the color of the paint and your skill level – you might see this transition between the two different materials if you don’t use a primer.
It can go over wood and some wallpapers without a primer.
A clay paint will not be washable. These would be contrasting needs. Clay paint is not suited for frequent cleaning. Grease and other contaminants can leave permanent marks.
For bathrooms, clay paint is not ideal, as it should not receive regular water exposure. I would not use this in a bathroom personally as the area around the sink will generally get splashed.
I like their basic Clay Paint. They also have a slightly more modified one that is called their Solvent-Free Wall Paint (NB all water-based paint is solvent-free as a general rule).
I couldn’t pick up much of a difference between them (odor-wise), but the solvent-free paint was smoother in its final finish, and it is more washable.
Ingredients and Additives in BioShield Clay Paint
Ingredients in Bioheild Clay Paint:
Water, clay, porcelain clay, chalk, alcohol ester (as a binder, this is the PVA), cellulose, pigments, preservatives (you can email them for the details on the preservative, they are common ones but not benign).
Ingredients in BioShield Solvent-Free Wall Paint:
Water, chalk, asbestos-free talcum, titanium dioxide, polyphosphate (a water softener), cellulose, alcohol ester, sodium hydroxide, and preservatives.
What I like About BioShield (Pros):
- The purest or least “offensive” paint on the list, in my estimation.
- The lowest odor paint I have ever used.
- No-VOC. Usually tolerable for the chemically sensitive.
- Chemically sensitive folks may even be able to apply it themselves.
- No time (or less time compared to some others) needed for offgassing before reentering the room.
- 100% transparency in ingredients.
- No primer needed in some applications.
What I don’t like about BioShield (Cons):
- Not washable, it stains easily, means you either need to apply a labor-intensive wall glaze, or AFM Penetrating Waterstop in high impact areas. (The Solvent-Free Wall Paint is more washable.)
- You may need another paint option for the bathrooms.
- You may need a primer over new drywall that doesn’t have a skim coat (and you will have to choose a primer that you tolerate).
- They only ship to the 48 states (not Canada).
Application Tips for BioShield Clay Paint
I applied BioShield Clay Paint and Solvent-Free Wall Paint without a primer over paper-based drywall (2 x 2 pieces with no drywall mud).
I found it relatively easy to apply and I really liked the finish. I thought it would be more difficult to apply than it was.
The application is not the same as regular paint or RomaBio which went on more conventionally and was more forgiving of my medium nap roller and beginner’s technique.
I did have trouble finding the right brush and roller that did not leave such a textured finish. A more skilled painter should not have as much trouble with this.
My medium nap roller left it quite textured. If you are new to painting or to clay paints, you might want to test out your brush and roller to see what the texture will look like. I was not happy with my texture and the company would not recommend a specific brush or roller.
It is a plus that this can be applied with a roller. A low nap roller is recommended for a conventional-looking finish on drywall, like Wooster 3/8th nap rollers.
A beginner should do a test sample on a test piece of drywall.
Two coats are required, with a longer dry time in between than many other paints. Cures in about 10 days. I will report back with my spatter tests when it’s cured.
I also tried the Wall Glaze on top of the paint as a protective coating. The ingredients of the wall glaze are cellulose, alcohol ester, silica, carnauba wax, clay, water, and preservative.
How did it Hold up?
Without the glaze, the Clay Paint held up pretty well to mustard. I had to use the Magic Eraser to get it out completely, and like with RomaBio that did remove a tiny bit of paint (which was not noticeable on the wall, only on the sponge).
It did not do as well with the mayo, which left a slight oil stain. It was not very noticeable after cleaning it off.
3. Annie Sloan Chalk Paint (on the Wall) Review
Annie Sloan is well known for their Chalk Paint®. It’s best known as a furniture paint, but it can also be used on walls.
They do have a separate paint that is labeled as wall paint. Right now it is not available in North America (only Europe), I tried their regular Chalk Paint on paperbacked gypsum wallboard.
The most interesting aspect of this paint is its self-priming ability over a wide range of surfaces. You don’t need to prime or sand most surfaces. The finish is ultra-matte, a chalk-like look.
There are not many non-toxic paints that can be used on cabinets, this is one of them. (I mention the others in the post on paints and sealers). What’s easy about this one is it goes over many cabinets types and finishes without sanding or priming.
It also works as one of the only non-toxic chalkboard paint (to write on).
The most obvious downside is we don’t know what’s in this paint. They claim extremely low VOCs. I don’t find it as potent as regular paint but it does resemble an artist’s paint (not an acrylic odor though).
I cannot quite identify what is in this by the odor. Some extremely chemically sensitive folks have done well with this paint, some have reacted. I think it’s certainly worth testing out for your project.
Like the clay paint, it has a matte finish that is not scrubbable. The company does not recommend using Chalk Paint on walls in kitchens, bathrooms and walls that require a tougher, scrubbable finish.
Like with clay paint, you can use wax over it to provide more protection and durability to use it in high impact areas. But waxing a whole wall is a very big job.
I tried the Annie Sloan Wax. It smelled like petroleum products to me and I did not tolerate it. It was the only finish in this post I did not tolerate (just the wax part).
That’s not a deal-breaker for me, you can use this without a wax or use a different brand of wax finish. I tested a couple of other finishes over it, and will report back in part two on the wax coats and how everything held up to my stain tests.
If you are in Europe they do recommend the wall paint for kitchens, bathrooms, and walls that require a tougher, scrubbable finish. (The wall paint does not require the wax and is not considered breathable).
What I like About Annie Sloan Chalk Paint (Pros):
- Very Low VOC.
- Low odor, will be suitable for many chemically sensitive folks (but not all). To my nose, it’s much lower odor than Romabio.
- Very versatile – it can be used on walls, floors, wood, cabinets, concrete, metal, matte plastic, earthenware, brick, stone and more.
- Rarely is sanding or priming the surface first necessary.
- Unique matte, chalk-like look.
- One coat and no primer needed, make this the fastest to apply.
- The artist quality to this paint and its pigment would make me choose this one for a wall mural or decorative design (though it is very fast drying so it’s not easy to blend on the surface).
What I don’t like about Annie Sloan Chalk Paint (Cons):
- I have no idea what is in this paint. Hardly any hints to any of the ingredients. Very few claims about what’s not in it either. The SDS only lists two alcohols and ammonia – nothing about the binder/polymer or minerals.
- Some extremely sensitive folks may not tolerate it, or may need to leave the room until it’s cured.
- The dark red that I used did need a second coat to be totally even.
- I didn’t tolerate the wax, and many people I know would not tolerate it.
Tips for Applying Annie Sloan Chalk Paint to Walls
For most purposes, one coat of paint is enough (it wasn’t for me and the dark red, though the coverage was very impressive compared to every other paint I have ever used). You don’t need to prime walls.
You can apply it with a brush, make sure you use a natural or natural/ synthetic mix brush like this Annie Sloan brush. You may want to try Purdy White Bristle (natural bristle) or the softer Purdy Ox Hair Brush.
Annie Sloan prefers brush application with random brush strokes to a roller application. But you can use a roller to apply it to the drywall.
It seems that most people use a roller, as it is easier for most people. You will want a high-density foam roller.
I used a natural bristle chalk paint paintbrush for a 2 x 2 drywall sample and I was happy with the look of the brush marks. For a bigger area, you will want a larger brush than the chalk paint brushes used on furniture.
I recommend painting a sample on a piece of 2 x 2 drywall to test out your brush type, technique and texture. As well as testing to see if you only need one coat.
It’s 30 days for a full cure. For bedrooms and low impact wall rooms, you don’t need to wax it.
If you are waxing it, this large wax brush can be used to apply it to the walls. Remove excess with a cloth. The wax was not tolerable for me, and I would not recommend it for most chemically sensitive folks.
How did it Hold up?
With the wax it held up extremely well to mustard and mayo.
The unsealed Chalk Paint held up fine to mustard – perhaps there is a limit to how much you could wipe it or scrub it but it did hold up to my test.
I also tried the BioSheild Glaze and that helped it hold up perfectly to mustard and mayo as well.
4. Charleston Lime Paint Review
Charleston Limewash makes lime wash and lime paint. Lime wash is just for painting over plaster or masonry. The lime paint can go on primed or already painted walls.
What I like about this paint is simple ingredients and full disclosure.
The odor is familiar to anyone who has used even basic acrylic artists paints.
Once dry, this would qualify as 0 VOC. With lime as the main ingredient, it does not require a preservative mildewcide in it.
Ingredients of Lime paint:
The paint is made of 45% calcium hydroxide (lime), and approximately 5% acrylic. They claim those are the only ingredients (pigments and water of course, too).
What I like about Lime Paint (pros):
- Mild acrylic odor, will cure to 0 VOC.
- I found it more tolerable than conventional acrylic paints due to the high lime content.
- Full disclosure of ingredients.
- No preservative is needed with lime.
What I don’t like about Lime Paint (cons):
- The main drawback is that it needs a primer on the wall first. It’s likely that you will end up using ECOS or another similar 0 VOC primer.
- It has 5% acrylic, so it is not totally natural, and not everyone will do well with acrylic.
- They don’t provide a wax or topcoat to go with it.
- The light blue color I choose required a primer and three coats, making it the most labor-intensive of the paints here.
- The paint did not have an even look.
- It’s tricky to apply – you should do a sample board first.
Application Tips for Charleston Lime Paint:
The color was bright blue in the container but it dried to a baby blue. It was difficult to apply evenly, and because it dries to a different color than when wet, and dries fast, it was not that easy to tell if it was applied evenly.
I used straight across brush strokes, random brush strokes are recommended.
After two coats I could see how it was evening-out. I applied three coats, and I was not left with an even finish with two or three coats. You will want to experiment here with brush types, dilution rates (don’t go too thick as it will be harder to get it even), and practice to make sure you get the look you want.
I preferred a smaller brush. On a wall, you will need a larger brush. Something smooth like Purdy Nylox. The company did not recommend a specific brush.
Limepaint and Annie Sloan dried super fast, you had to work fast. Biosheild and Romabio were not too far behind but had a slightly longer work time.
How did it Hold up?
The lime wash with no coating would not be expected to hold up to my mustard and mayo test. Both stained it.
The mustard was removed with the Magic Eraser which removed a lot of paint and left a very obvious area of paint removal. The mayo stain was even worse. I will test out patching that up but with the way the lime paint shows overlaps, I don’t think I will be able to.
Summary – Which Mineral Paint to Choose:
- Use RomaBio if you want an easy solution that applies like typical paint and is matte, breathable, washable. And, you can tolerate the offgassing.
- Use BioShield if you are in the most sensitive category and want the most benign option.
- Try Limepaint if you do better with an acrylic binder.
- Try Annie Sloan if painting over something difficult to prime, if you want to save time with just one coat, or you like the look of it better.
Paints that Didn’t Make the List:
- Earthborn Paints – are available only in the UK/Europe
- Green Planet Paints – these paints are a little different. I wanted to include them though it was too difficult for the company to send a sample to Canada (also they don’t have sample sizes). This is a soy-based paint that is not quite like any of the other options out here.
- Auro – In Europe they sell the more pure mineral paint but they do not sell this in North America at this time.
- Fusion Paint – This is a furniture paint. It is an acrylic mineral paint. I don’t know what percent is acylic, but I’m not sure what classifies it as a “mineral paint”. They do claim 0 VOC. The percent of acrylic would change whether I classify this as a mineral-based paint or an acrylic paint.
- Milk Paint – doesn’t really go on the new drywall so easily, so it was not included here. On new drywall, it requires a bond coat, then at least two coats of milk paint. The finish can crack on the wall and it also requires a sealer like hemp oil or finishing cream on top. Milk Paint could have been included here but one of the distributors convinced me not to.
- Farrow and Ball – Farrow and Ball is a latex/acrylic paint but they describe it as a mineral paint: “We start by mixing chalk, china clay and titanium dioxide with water to create our base paint.” Many synthetic paints have these minerals as their base.
- ECOS – ECOS paint, the favorite of the 0 VOC paints currently, also contains chalk, clay and titanium dioxide like F&B, but it is still classified as an acrylic paint. I talk about 0 VOC conventional paints in the post on paints and sealers.
Note: All paints have minerals, a binder, a solvent and usually a preservative. In all of these water-based paints, the “solvent” is water. Any paint with a polymer binder that polymerizes is not technically “a mineral paint”. Paints that were largely mineral-based with a small amount of binder, or a less toxin binder were included in this post. Again, all wall paints have a binder!
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