This a deep dive into the best mineral paints: chalk paint, milk 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 and most natural paints that can go on interior walls.
These paints are also all breathable (have high perm ratings).
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. Alnost 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 something in here is 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 low 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, likely the mildewcide, 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 a lower odor in my opinion 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 near the top of the list.
Though it seems to be extremely similar to Farrow & Ball paint which is much easier to purchase, easier to apply, and more durable!
This has a high percentage of natural ingredients, the least amount of concerning additives and is very low 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.
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.
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 wood and some wallpapers 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.
Clay paint is not suited for frequent cleaning. Grease and other contaminants can leave permanent marks.
You can add their Wall Glaze or AFM Penetrating Waterstop to add more water resistance and cleanability – I tested both of these, more below. They recommend the wall glaze for areas like the kitchen and hallway.
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):
- A fairly pure option.
- One of the lowest odor paint I have ever used (alongside Farrow & Ball).
- 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).
- Not easy to apply and the company was not willing to help me choose a brush and roller.
- They only ship to the 48 states (not Canada).
- No apparent reason to buy this over Farrow and Ball. A very close alternative in my estimation, that you can buy in Canada, the US, and Europe. That seemed to be extremely similar in makeup and odor. It’s also a PVA based paint high in minerals.
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. But the company was not helpful with me in finding the right brush and roller.
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. After some digging, 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. Splatter tests below.
I also tried their 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 and Solvent Free Wall paint held up so-so to mustard. I had to use the Magic Eraser, and like with RomaBio, that did remove a tiny bit of paint.
They did not do as well with the mayo, which left an oil stain.
I put it to the test after applying the Wall Glaze and AFM Penetrating Waterstop.
Solvent-Free Paint worked the best with AFM PWS. No stain from either mustard or mayo and it retains the same color and sheen.
Wall Glaze also worked well on Solvent-Free Wall Paint but there is an ever so slight mustard stain.
Their basic Clay Paint held up best with their Wall Glaze. With also an ever so slight stain that cannot really be seen from a few feet away. AFM PWS did not help the Clay Paint hold up well.
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.
Chalk Paint for 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.
Unique Benefits of Chalk Paint
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. It can be used just as a primer if you don’t want the final chalk 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 main post on paints). 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).
But What’s in it?
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 (possibly a slight acrylic odor, but nothing close to as strong as a regular acrylic paint).
I cannot quite identify what is in this by the odor. Some extremely chemically sensitive folks have done well with this paint, a few have reacted. I think it’s certainly worth testing out for your project.
Comparison to Rust-Oleum Chalked
Chalked has an affiliate program and I believe this is why most blogs say they prefer this over Annie Sloan. Annie Sloan is in my opinion lower odor.
Chalked paint in my estimation has a much more obvious acrylic odor and I would guess the base is far more acrylic. The odor is far more similar to a regular 0-VOC acrylic-latex paint.
They both have similar coverage and work well at priming over difficult surfaces. Chalked is certainly less expensive and easier to locate via Amazon or the hardware store.
Where to Use it
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 anywhere else that requires 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 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.
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, over waxed shellac, 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.
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 Annie Sloan wax it held up extremely well to mustard and mayo.
The unsealed Chalk Paint held up OK to mustard – there is a limit to how much you could wipe it and get it wet but I would say it did hold up to my test. It did not hold up to mayo.
I also tried the BioSheild Glaze and that helped it hold up perfectly to mustard and mayo as well.
AFM Penetrating Waterstop did not help it hold up to mustard or mayo even though I had great results using this over clay plaster.
4. Milk Paint Review
Milk Paint is a truly natural paint. The only one on the list that is 100% natural. It is a true zero VOC paint that is biodegradable.
It’s almost always safe for those with extreme chemical sensitivities, even when wet.
Where Can You Use Milk Paint?
If your walls are raw plaster or gypsum Milk Paint will stick to these surfaces, no special prep is needed.
Don’t use over a joint compound that has latex in it though, it doesn’t apply as well to that.
It works well over raw wood, on glass and masonry. It bonds with masonry walls so well that it would be tough to remove.
Previously painted surfaces likely need to be washed with TSP to strip the paint and also need a bond coat (which is a concentrated acrylic). You can apply it to other difficult to paint surfaces, like metal, by using the bond coat.
It can be used on kitchen cabinets but you need a durable topcoat over it. Wax and hemp oil can not endure a lot of water or harsh cleaning products.
What’s in Milk Paint?
Ingredients: milk protein (casein), limestone, clay, chalk, and natural pigments.
Applying Milk Paint
You mix the powder 1:1 with water. It was quite easy.
Depending on where you are applying Milk Paint and how durable you need it to be, you can choose from a number of topcoats including:
Natural oils: hemp oil, walnut oil (with wax), and, the most durable of the oils, tung oil. The oils tint the color, so make sure it’s compatible. Tung oil has the strongest odor of the three, hemp and walnut are both quite mild.
Natural waxes: like those from The Real Milk Company.
What I like about Milk Paint (Pros)
- The purest and safest paint out there. 100% natural and safe.
- Actually 0 VOC.
- Safe even when wet for the chemically sensitive. Almost everyone could apply this themselves.
- You don’t need a primer on most porous surfaces.
- You can choose from a variety of top coats.
- Easy to source this from Amazon or from Real Milk Paint.
What I don’t like about Milk Paint (Cons)
- If you are applying this to already painted walls, the number of steps involved does not justify this choice in my opinion.
- In most situations, you do need a top coat which is an extra step.
- If you need this to be super durable you need to go with a tung oil or durable water-based top coat. Those products have some odor and take time to cure and offgas.
My full test results are coming soon!
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. A great choice for masonry.
- Use BioShield or Farrow and Ball if you are very sensitive but still want something conventional (Farrow and Ball) or close to it (BioShield). Both are breathable, Farrow and Ball is more durable.
- Try Milk Paint if you want a truly 100% natural and safe product, and are painting over raw wood, gypsum, or plaster.
- Try chalk paint if painting over something difficult to prime like metal or shellac, 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. This is a soy-based paint but it is essentially an acrylic paint, just like conventional paints. The acrylic is naturally derived.
- 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 acrylic, 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.
- 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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