Why Would you Want a Breathable Paint?
Some wall assemblies call for breathable walls. In Passive House design high permeability of interior wall coverings is often specified to ensure that the system is highly breathable to the interior.
In some assemblies the opposite is called for, a vapor retarder paint (a less breathable than usual paint) is specified.
All latex paints are somewhat of a vapor retarder.
This post provides options for more breathable paints as well as other high perm wall coverings like plaster and wallpaper.
It’s a good idea to have breathable paints on the interior of basement concrete walls as that is a crucial area that should be able to dry to the interior.
The perm rating is the measure of the permeability of moisture through the coating. The higher the number, the higher the permeability (or breathability).
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Perm Ratings of Conventional Paint
- Alkyd (oil-based) semigloss 0.57
- Alkyd flat 19.9
- Latex paint generally in the 2-3 perm range it can be as high as 8-10 perm. Flat paints are more permeable.
- Latex vapor retarder paint 0.45
Breathable Paints & Wallcoverings
Annie Sloan Chalk Paint
- What is it: A paint that is high in calcium carbonate (25-50%), with an unspecified (but likely acrylic) binder, it has a chalky finish that is not durable to water without a topcoat.
- Perm Rating: Annie Sloan Chalk Paint claims to be permeable but did not have an official perm rating. Any paint that needs a topcoat in order to be durable to water is going to be breathable. Though the choice of topcoat will of course dictate the final perm rating.
- Where to Use it: On new drywall, previously painted walls, wood, concrete, and masonry.
- Where I Would Use it: I really like Chalk Paint and I would use this on wood walls, drywall and concrete walls, if the area isn’t expected to get very dirty I would leave it without a sealant.
- Where to Buy it: Find a local stockist through their website.
Rust-Oleum Chalked Paint
- What is it: A competitor to Annie Sloan, this chalked paint has similar self-priming abilities and a super flat finish. They do disclose the binder as an acrylic. It appears to me to have more acrylic in it than Annie Sloan.
- Perm Rating: The perm rating has not been tested, but I would expect high perm rating due to low binder levels in Chalked Paint.
- Where to Use it: Same applications as Annie Sloan.
- Where I Would Use it: I would use this on wood walls, drywall and concrete walls, if the area isn’t expected to get very dirty I would leave it without a sealant.
- Where to Buy it: Easy to find on Amazon or the hardware store.
Romabio Masonry Flat
- What is it: A pure potassium silicate paint. Not washable. A great pure option for basement concrete walls. No mildewcide is added – it’s naturally mold resistant due to the mineral content.
- Perm Rating: 70+ (completely breathable)
- Where to Use it: Interior and exterior masonry wall surfaces (cementitious, brick, stucco). Interior and exterior wood surfaces and trim.
- Where I Would Use it: A top pick for interior basement concrete walls if you want it to be totally breathable but don’t need it to be particularly washable.
- Where to Buy it: Sometimes available on Amazon, otherwise check their website for local dealers.
RomaBio EcoDomus Interior Paints
- What is it: A silicate paint (a mineral paint). Potassium silicate is the primary binder, but it also has EVA and an undisclosed polymer. It’s one of the only breathable and washable options. Similar to the above paint but more washable and less breathable.
- Perm Rating: Between 20 and 65, depending on whether it is their gloss, satin, matte or super flat. (Less glossy = more breathable).
- Where to Use it: Unpainted drywall, raw wood, natural stucco, plaster, absorbent brick, and stone. With a primer, it can also be used over previously painted surfaces and concrete/concrete based stucco.
- Where I Would Use it: A top pick for interior gypsum (drywall), or tongue and groove wood walls as it’s a great mix of breathable and washable. My full test results of this paint are here.
- Where to Buy it: Amazon
Farrow and Ball Paint
Farrow and Ball Estate Emulsion
- What is it: A conventional paint that is matte, breathable, and also wipable. It is very low in odor and the main binder appears to be PVA.
- Perm Rating: It’s not clear what the exact perm rating is but they do claim it’s in the most breathable category.
- Where to Use it: On primed walls, or unpainted plaster.
- Where I Would Use it: Interior walls, especially drywall when a super low odor conventional paint is needed and the exact perm rating is not needed.
- Where to Buy it: At a local dealer or via their website.
Real Milk Paint
- What is it: A 100% natural paint that comes in powder form. It’s made of milk protein (casein), limestone, clay, chalk, and natural pigments. You mix it yourself with water. It requires a topcoat to be durable to water, though the SafePaint formula can take a wet hand on the wall no problem. You can use many different coatings as the topcoat if you need it to hold up to stains (covered here).
- Perm Rating: The Milk Paint itself is breathable but the final perm rating will depend on your topcoat. The natural oils are the most permeable option.
- Where to Use it: You can technically use it on new drywall. The original formula gives an uneven finish and the SafePaint is far more conventional in its application. Both look great on raw wood. It can be used on raw concrete as well.
- Where I Would Use it: I like this finish on wood mainly, I would use it on concrete walls. The last place I would want to use it on drywall – but for someone who is too chemically sensitive for all other options it can be used.
- Where to Buy it: Real Milk Paint direct from them or from Amazon. Old Fashioned Milk Paint from Amazon.
Linseed Oil Based Paint
Linseed oil-based paints are usually fairly permeable but they do span quite a range of perm values so you will want to ask each company specifically.
I have seen them range from 2 to 20 perm.
AFM Naturals Interior Paint
- What is it: A natural oil-based paint. The oils are soybean, flaxseed (linseed), and thistle oil. The base is natural minerals, the polymer is polysiloxance (a silicone). Metallic driers are used (but no lead or cobalt). They also make a primer.
- Perm Rating: Breathable the company says, but no official perm rating.
- Where to Use it: Primed interior walls and ceilings, properly cured and primed plaster, masonry, woodwork, and primed metal.
- Where I Would Use it: I love the idea of natural-based products so I would be keen to use this on interior walls (like drywall) if linseed oil is tolerated and if the exact perm rating is not needed.
- Where to Buy it: Through Green Design Center.
Other Breathable Wall Coverings
- Clay plaster
- Lime plaster
- Gypsum plaster/Plaster of Paris – perm 11-15 (source)
- Concrete based stucco – perm 3.8 – 5.8 (source)
Paper-based wallpapers with water-based inks are breathable.
My wallpaper post goes into detail on many more brands.
You definitely don’t want to use vinyl wallpaper (including vinyl coated wallpaper) or acrylic wallpaper on exterior walls when you use AC inside. Those wallpapers are a vapor barrier and in that situation you can easily cause mold.
Corinne Segura is a Building Biologist Practitioner with 7 years of experience helping others create healthy homes.
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