Technically, a mineral paint is a paint made with potassium silicate as the main binder. These are also called silicate paints. Any paint with a polymer binder that polymerizes is not technically a mineral paint.
Some companies are producing paints that they call mineral paints that are simply regular paints with mineral content. A paint heavy in clay or in chalk could be loosely described as a mineral paint, but usually, this is deceptive.
Paints are classified by the binder that they use. Calling any paint a mineral paint because it contains minerals is marketing lingo. All paints use minerals as the base filler/thickener.
Paint types, which ones are really mineral paint?
Zero-VOC acrylic latex paint – contains minerals like calcium carbonate (limestone), kaolin clay, and titanium dioxide. But this is classified as acrylic paint because the main binder is acrylic. Examples, ECOS Paint, a 0-VOC wall paint, and Fusion Paint a furniture paint that markets itself as a “mineral paint”.
Non-acrylic latex paint – contains a mineral base of calcium carbonate, clay, and titanium dioxide. The binder is PVA or EVA instead of acrylic. Examples, BioShield “clay paint” and Farrow and Ball paint.
Chalk style paint – this paint is defined by its heavy calcium carbonate content (limestone, aka chalk). It also contains titanium dioxide for the light colors. Chalk-style paints can contain clay, and likely contain talc. The binder is PVA and/or acrylic.
Milk Paint – is made with a mineral base of limestone, clay, chalk, and natural pigments. The binder is milk protein (casein).
Silicate Paint – is made with calcium carbonate, titanium dioxide, and possibly talc. The binder is potassium silicate.
As you can see all paint could be classified as mineral paint since minerals make up the base of the thickener.
I tested and compared the most natural, and lowest VOC options, that were low in synthetic additives:
- Silicate paint (the only one that is technically a mineral paint)
- Clay paint (high in clay, low in binders and additives)
- Chalk paint (high in calcium carbonate, low in binders and additives)
- Lime paint (high in calcium carbonate, low in binders and additives)
- Milk paint (all-natural, made with minerals and a natural casein binder)
This article reviews my experience with silicate paints and compares this type to the other contenders that have high mineral content and are low in synthetic additives. (I tested them all on drywall).
Why go with one of these more natural mineral-based paints:
- 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 sensitive people to apply.
- These paints are breathable, which is specified in many mold-preventative wall assemblies (for example in passive house design).
- They are especially well suited to concrete (and some only work on masonry), though many work great on any porous surface like drywall and wood.
- Some of these paints can give a natural look and feel to a room compared to regular acrylic latex paints.
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.
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). Silicate is a very safe binder.
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 (a rare combo).
Silicate paints are the only type of paint that can technically be called a “mineral paint”, 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 – compared to clay paint, chalk paint, lime paint, and milk paint.
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 zero-VOC paints, but something in here is contributing to that odor that is associated with “new paint smell”.
What are the Ingredients 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, and 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 zero VOC paints like ECOS and Ben Moore do not have a high perm rating. Most natural paints, like those in this article, are not washable.
- One of the few washable flat (matte) sheen mineral paints I found that does not require a sealer to be washable.
- Durable and not easily stained by oil, or 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 for any 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 zero-VOC paints like ECOs. It’s not clear that odor and VOC-wise, that it’s better than ECOs or other zero-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).
- Undisclosed ingredients.
Application Tips for RomaBio EcoDomus Mineral Paint
EcoDomus can be applied with a brush, roller, or spray like any traditional paint. This was the most like conventional no 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 no-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 need a 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, of both 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 gray color that the Eraser pulled up a little paint. It’s not obvious on the drywall.
They say you can clean it with mild dish soap or another mild cleaner with a soft rag or soft sponge.
2. Kiem Mineral Paint Review
Kiem Mineral Paint is a German brand that is also available in the US. They make a wall paint that is silicate-based with only a little acrylic binder.
This paint is extremely low odor, much lower odor than Romabio. And certainly much lower odor compared to the more typical acrylic wall paints.
I tested the Kiem Interior Mineral Wall Paint. It’s listed at 0-VOC and it’s for use on new or previously painted drywall, plaster, brick, stone, concrete, or stucco. (Not for use on bare wood, plastic, wood trim, doors, windows or floors). It’s self-priming on both bare and previously painted surfaces.
It’s very vapor-permeable. Perm rating of 77.
What are the ingredients in Kiem Paint:
Silicate and calcite fillers, titanium dioxide, silica sol, water, polyacrylate, hydrophobing agents, thickeners, stabilizers, wetting agents, and defoamers.
Other Silicate (Mineral) Paints:
- Ecologic Potassium Silicate Paint – which is only for masonry
- BEECK Mineral Paint – silicate paint
3. Comparison: Mineral Paint v Clay Paint
In terms of the most non-toxic paints I found in North America, BioShield Clay Paint is near the top of the list. This paint is marketed as a clay paint since clay is the main mineral/filler.
This has a high percentage of natural ingredients, and the least amount of synthetic or concerning additives apart from Milk Paint which is totally natural. It is extremely low in odor.
It does have a PVA binder/polymer in it so it’s not technically classified as “a mineral paint”.
Clay Paint similarities with Mineral Paint
- Both paints are breathable.
- Both are high in minerals and low in synthetic binders.
- Both paints are technically 0-VOC.
- Some situations do not require a primer on drywall for both.
Clay Paint differences compared to Mineral Paint
- Clay paint is not suitable for frequent cleaning. It can easily be stained by grease and other substances. You can add their Wall Glaze or AFM Penetrating Waterstop to add more water resistance and cleanability – I tested both of these. The topcoats are recommended for areas like the kitchen and hallways.
- Clay Paint is not a good idea on bathroom walls.
- 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 the transition between the two different materials if you don’t use a primer. 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).
- Clay Paint is definitely lower in odor, especially when wet,
- Clay Paint is more suitable for folks with extreme sensitivities, especially if applying it ourselves.
- Clay Paint has full disclosure on ingredients.
- Clay Paint is not that easy to apply and the company was not willing to help me choose a brush and roller. Romabio was very easy to apply, just like a regular paint.
- Clay Paint requires making up a sample board to test your application.
My post on Clay Paint shows my full tests and full review.
A good alternative to BioShield Clay Paint is Farrow and Ball Paint Estate Emulsion which seemed similar to me. Farrow and Ball is easy to apply, just like any regular wall paint.
Ingredients in Bioheild Clay Paint:
Water, clay, porcelain clay, chalk, alcohol ester (as a binder, this is the PVA), cellulose, pigments, and preservatives.
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.
4. Comparison: Mineral Paint v Chalk Paint
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. I tested this out alongside Romabio mineral paint and this is how it compares.
Chalk Paint is not often used on walls because on its own it is not very durable to stains. A dirty hand on the wall could easily leave a mark. It’s not recommended for bathrooms and kitchens.
For some people, leaving the Chalk Paint without a topcoat in a room like a bedroom (with no kids!) will be no big deal. You can add a wax topcoat for extra durability to water and stains which will bring its performance closer to that of a mineral paint.
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 known and suspected ingredients in Annie Sloan Chalk Paint are listed here.
Annie Sloan Similarities to Romabio Mineral Paint
- Also a breathable formula.
- High in minerals and low in synthetic binders.
- Both have a long cure time.
Annie Sloan Differences Compared to Romabio Mineral Paint
- Annie Sloan is not scrubbable or as durable to water and stains, it needs a wax coat to try to compete.
- Chalk Paint is much lower in odor when wet and faster to reach odorless.
- Chalk Paint has a better ability to self-prime over a wide range of surfaces and doesn’t require a primer. This extreme versatility and ability to stick to many surfaces without a primer is one of the main benefits of Chalk Paint. It sticks to and can be used on walls, floors, wood, cabinets, concrete, metal, matte plastic, earthenware, brick, stone, over waxed shellac, and more.
- It’s possible that you can get away with one coat of Chalk Paint in some circumstances. Though you often need two coats. Romabio is two coats and in some cases, you need a primer as well.
For tips for applying Annie Sloan Chalk Paint to walls see my post dedicated to Chalk Paint.
Rustoleum Chalked is similar but definitely has an acrylic binder, is a little higher odor when wet, doesn’t always self-prime, is less expensive, and is a little more durable.
5. Comparison: Mineral Paint v Milk Paint
Milk Paint is a truly natural paint. The only one on the list that is 100% natural. It is a true zero-VOC and toxin-free paint that is biodegradable.
It’s almost always safe for those with extreme chemical sensitivities, even when wet.
If your walls are raw plaster or gypsum drywall, 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. The original formula should be used on raw wood.
The SafePaint wall formula is the only one that can go over regular primers and some regular paints. I used it in the photo above on raw drywall, and I couldn’t get it perfectly even at the seams.
It does require a topcoat to be durable, my post dedicated to Milk Paint goes over those options as well as tips on how to apply it.
Milk Paint Similarities to Romabio Mineral Paint
- Both are breathable.
- Both are high in mineral content.
- Both are technically 0-VOC.
- Both can be used without a primer in some circumstances.
Milk Paint Differences compared to Romabio Mineral Paint
- Milk Paint is 100% natural.
- We have full disclosure on what is in Milk Paint.
- Milk Paint is much lower in odor when wet and is more suitable for people with extreme sensitivities.
- Milk Paint is not wipeable without a topcoat, where Romabio is, Romabio is much more durable.
- You should make up a sample board for Milk Paint, because it’s not that easy to get it even on the walls.
Ingredients in Milk Paint
Ingredients: milk protein (casein), limestone, clay, chalk, and natural pigments.
Summary – Which Mineral Paint to Choose:
- Use RomaBio or Kiem if you want an easy solution that applies like typical paint and is matte, breathable, and washable. A great choice for masonry. Kiem for a super low-odor option.
- 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.
- Try Milk Paint if you want a truly 100% natural and safe product. It’s ideal over raw wood.
- Try Chalk/ed Paint if painting over something difficult to prime like metal or shellac, or if you want to save time with just one coat.
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 paint. 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 Mineral Paint – did not make the list because this is an acrylic paint. The company says very clearly that this is made with 100% acrylic binder. Just like all other paints, the fillers/thickeners are minerals.
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