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 acrylic latex paints are somewhat of a vapor retarder (class III 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
Chalk Paints
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, Walmart or at local stores.
Mineral Paints
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
Kiem Mineral Paint
What is it: A silicate paint (a mineral paint) with just a touch of acrylic. It’s a breathable and washable options.
Perm Rating: Between 75 and 85.
Where to Use it: Use on new or bare, plaster, drywall and wallboard, masonry, concrete and stucco.
Where I Would Use it: A top pick for interior gypsum (drywall). My full test results of this paint are here.
Where to Buy it: Through Green Design Center.
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 binder is VAE in their Estate Emulsion, Estate Eggshell, Full Gloss, and Dead Flat. These sheens are acrylic free.
- Perm Rating: Their perm ratings are in European units but they did say in an email that Estate Emulsion and Estate Eggshell would convert to approximately > ~25 Perms.
- 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.
Milk Paint
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.
Another brand of linseed oil paint is Allbäck Linseed Oil Paint which I describe in my main article on paint.
Other Breathable Wall Coverings
Plaster
Breathable plasters:
- Clay plaster
- Lime plaster
- Gypsum plaster/Plaster of Paris – perm 11-15 (source)
- Concrete based stucco – perm 3.8 – 5.8 (source)
See my article on choosing a non-toxic plaster.
Some Wallpaper
Paper-based wallpapers with water-based inks are breathable.
Brands with particularly breathable lines include Farrow & Ball, which use their breathable paints to make the designs, and Veruso Lino, which is only paper and has no ink or paint.
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 8 years of experience helping others create healthy homes.
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Bee says
What I’m noticing is that if you go with permeable paints you suddenly don’t have really vivid bright choices, and no purple at all. That’s very frustrating, as I really hate muted shades and pastels, and want bright jewel tones and particularly blue-violets. :\ Yet I have lovely lime walls. I guess I have to go with wallpaper after all.
Corinne says
some of the brands have bright colors but they don’t have a full range of bright colors.
Friedrich Koch says
We have used lime wash for external and internal walls all over Europe for hundreds of years years and they still do it today. It kills all germs, is inexpensive but you need to wear goggles, mask and long sleeve protective gloves. Don’t beath hydrated lime power when you mix with water and get nothing into your eyes or onto your skin. I like to ask your forum what you think about lime wash as an alternative to other paint or plaster surface coating. AAC external walls have already a flat surface due to high accuracy of the product. When lime dries it absorbed CO2 out of the atmosphere and turns back to lime stone again. I like to read your comments. Thank you, Best Regards Friedrich Koch
My email is: [email protected]
Corinne says
I like Limewash.
Lawerence says
I meant Coastal Zone 4.
We are having the insulation and drywall installed in the next 2 weeks so I hope you get this message quickly and MemBrain is very difficult to source so delivery takes up to 10 days.
Lawerence says
I am in Coastal Zone 5 at edge of Zone 5. Building code requires a vapour retarder (even though vapour is a tiny portion of source of moisture in a wall compared to air leaks I have read). We are finishing a basement, Below grade is insulated with XPS. Above grade stud walls will be Knauf fiberglass insulation.
My wife and I are seniors and chemically sensitive.
I don’t like poly vapour readers as it smells strongly and it affects us. Also 6 mil is very impermeable.
Do you know if MemBrain smells or degasses like poly. It would be very expensive to buy and we only need 200 square feet of a 1000 sq ft roll so if you know about smell and degassing, it would be helpful.
The vapour retarder paint seems like an alternative but risky if we react to the paint. I tried a Sherwin Williams sample on a piece of drywall. Unpleasant smell when applying and drying but in two days it seems to be gone. We would only need to use this on the above grade wall, 2oo sq ft.
Corinne says
I haven’t sniffed the smart barriers.
Enda O'Kane says
Installing Insulation in attic. Wall cavities already filled.
Am due to re paint all my ceilings. Want to use a paint to help reduce vapour in attic which has caused some flakes of plaster falling from my slates over the years in this pre war house.
Thankfully no mould or timber damage.
I am aware of these smart vapour barriers/retarders but these are difficult and time-consuming to install.
Would two coats of latex paint reduce the vapour penetration?
Do you know of a latex vapour retarder paint?
Corinne says
It’s not clear where you want to use a vapour retarder paint and where the moisture problem is. It’s usually not a good idea to use a vapour retarder paint which is why I don’t list them.
Dan Wood says
An alloy of lead and tin is still widely used in construction. Lead-based paint was banned in 1978, but researchers have shown that paints, including those by well-known various manufacturers, do contain lead. So only in 5 out of 21 prototypes the level of lead did not exceed the maximum recommended indicator of 0.009%. That is why builders should renew their lead certificates every 5 years
Corinne says
Hi please commment with this research about current house paints containing lead.
Jen says
Sorry – I meant to say that polyethylene sheeting will trap water in the interior wall assembly and promote mold growth.
Jen says
Thanks so much for this information!!!
It would be helpful to provide a suggestion for no or low VOC latex paints that serve as a vapor retarder. I live in zone 5 where codes call for an interior vapor barrier in the wall assembly. I’m trying to avoid polyethylene sheeting which is likely to trap mold in the interior wall assembly and facilitate mold growth. Suggestions?
Corinne says
I would not recommend vapour retardant paints so I would not list them here. You might look at the “smart” membranes.
Jen says
Do you not recommend them because of the VOCs? I cannot find any no VOC options and the lowest VOC option I found was 44g/L. Thank you
Corinne says
no, because it’s almost never a good idea to block moisture that way. Especially a bad idea if you use AC.