Clay Based Paints (For Walls) – My Testing & Review

Out of the most non-toxic mineral-based paints I found in North America, BioShield Clay Paint is near the top of the list.

This clay paint has a high percentage of natural ingredients and the least amount of concerning additives out of any liquid paint available. It is also extremely low in odor.

The only paint that is more natural is Milk Paint, but Milk Paint is tricky to use on drywall. Clay Paint is the most natural paint you can use on interior drywall.

It is called a Clay Paint because clay is the main mineral filler. When comparing this with Chalk Paint, Clay Paint is higher in clay than calcium carbonate and Chalk Paint is higher in calcium carbonate. Both of these paint types can be free of acrylic plastic as the polymer, and use more benign PVA or EVA binders.

I found the odor of this clay paint, even straight out of the bottle, to be mild and non-offensive. Depending on your level of sensitivity, this may smell just slightly like polymers or it might smell totally benign to you – more like food than paint.

I gave two types of BioShield Clay Paint a test to see how it applied (not that easy!) and how it held up to stains (this varied by stain and topcoat as you will see).

I also compare clay paint to a slightly more conventional high mineral paint – Farrow & Ball, which is easier to procure, easier to apply, and more durable to water and stains.

Let’s dig into the testing to see if using Clay Paint is worth the hassle.

This post is not sponsored by BioShield, and BioShield does not have an affiliate program. This post contains other affiliate links. Upon purchase, I earn a small commission at no extra cost to you.

BioShield Clay Paint Review

BioShield Clay Paint 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.

Like every other paint that can go on new drywall, it does have a binder/polymer in it. The polymer is probably PVA or PVOH. It does polymerize so it’s not technically classified as a “mineral paint”.

It can go over wood and some wallpapers without a primer.

Durability

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.

Types of BioShield Paint

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 more washable.

In Australia, this is called Volvex paint.

Ingredients and Additives in BioShield Clay Paint

Ingredients in BioShield Clay Paint:

Water, clay, porcelain clay, chalk, alcohol ester (as a binder, this is the PVA), cellulose, pigments, 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.

What I like About BioShield (Pros):

• A fairly pure option.
• One of the lowest odor paints 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 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 that 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).

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 mineral paint, 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?

I put it to the test after applying the Wall Glaze and AFM Penetrating Waterstop.

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 Mineral Paint, that did remove a tiny bit of paint.

They did not do as well with the mayo, which left an oil stain.

Solvent-Free Paint paired 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 paired 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.

Clay Paint v. Farrow and Ball

Farrow and Ball Paint is another paint that is high in minerals and is made with a PVA and or EVA binder. It does not contain any acrylic binder.

They often market it by presenting it as high in natural mineral content. It certainly contains clay, but we don’t have the exact breakdown of ingredients to compare them accurately. In my opinion, these two paints seem very similar.

It’s extremely low in odor even when wet, just like BioShield Clay Paint.

Comparison: Farrow and Ball v. BioShield Clay Paint

• Both are high in minerals
• Both are acrylic free and use a more benign binder (PVA and or EVA)
• BioShield may well be lower in synthetic ingredients, we don’t know everything that is in Farrow and Ball
• Both are extremely low odor
• Both contain the same preservative
• Farrow and Ball applies like a conventional paint, whereas BioShield is tricker and has its own technique
• Farrow and Ball is more washable and more durable to stains
• BioShield needs a topcoat to be durable to stains
• BioShield is sold online, Farrow and Ball is sold online and in stores
• Both come in sample sizes
• Cost: BioShield $60 per gallon plus shipping, Farrow and Ball $100 per 2.7 L (0.6 gallon)

For those who are sensitive to chemicals, I would suggest getting a sample of each one.

I have tested both of these options and I prefer Farrow and Ball, since the application and durability outweigh the downsides of cost and more unknown ingredients for me.

Clay Paint v. Chalk Paint

The main difference between Clay Paint and Chalk Paint is that Chalk Paint uses calcium carbonate as the main mineral which leaves it with a chalkier look.

Some brands of Chalk Paint like Annie Sloan also appear to be free of acrylic binders, leaving Annie Sloan and BioShield as two pretty similar paints with a slightly different makeup of minerals and possibly the same binder (it seems to me).

Both are extremely low in odor.

The main draw of Chalk Paint is that it can self-prime over almost any surface even difficult to paint ones. Clay Paint does not have this benefit.

Comparison: Chalk Paint v. Clay Paint

• Both are high in minerals and have a matte look
• Both can be extremely low in odor depending on the brand (Annie Sloan and BioShield are low odor)
• Both can be free of acrylic binders, using non-plastic binders (depends on the brand)
• Both can be used on the wall, but both require a topcoat to be durable to water and stains
• Chalk Paint does not require a primer on drywall, while Clay Paint does in some cases
• Chalk Paint can go over almost anything, like shellac or oil-based paint, Clay Paint can not
• You can sometimes get away with just one coat of Chalk Paint

Clay Paint v. Milk Paint

The main difference between Clay Paint and Milk Paint is that Milk Paint uses an all-natural binder (casein) and contains no preservative as long as it’s a totally pure brand that comes in powder form.

I tested regular Milk Paint and SafePaint Milk Paint which is formulated for gypsum board drywall and it certainly applied much more evenly. However, it wasn’t perfectly even and the main drawback of Milk Paint is it’s hard to get that even look that you get from a paint in a can. And although Bioheild was a little finicky, it still applies more evenly (once you figure out the brush and roller technique).

Comparison: Clay Paint v. Milk Paint

• Milk Paint is 100% natural with no synthetic binder or preservative, while Clay Paint has a synthetic binder and chemical preservative
• Both are extremely low odor but Milk Paint could be preferred for those who only do well with natural odors
• Milk Paint can be used on drywall but it’s difficult to get it to look even, BioShield Clay Paint is finicky too but a little easier to get even. Farrow and Ball, if you consider that a Clay Paint, goes on perfectly even.

Which Paint Should You Pick?

I would consider BioShield Clay Paint if you want a mostly natural wall paint, and if the tradeoff is worth it for you. You will have to use a topcoat to have durability and test out your application technique to really get a nice looking finish.

Personally, I would choose Farrow and Ball over Clay Paint if I wanted the benefits of a high mineral paint, with no acrylic binder and extremely low odor.

I would consider Chalk Paint for priming over difficult to paint surfaces, like over a shellac or over an oil-based paint. It’s as low in odor as Clay Paint, and it also requires a topcoat to be durable, but has this amazing self-priming ability that no other (mostly) natural paint has.

Milk Paint is better suited to wood and terra-cotta, but you could use it on a wall. Those with severe chemical sensitivities may want to go with this option, the only one that is truly 100% natural and non-toxic, even though it’s hard to get it even on the walls.

Related Posts:

Mineral Paint (silicate paint) review

Chalk Paint full review

Zero-VOC synthetic wall paints

Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.