How to stop your basement walls trapping moisture.
Cellars are naturally prone to damp and condensation, especially in older properties. Choosing the wrong type of paint can make the problem worse by trapping moisture behind the surface, leading to mould, peeling, and flaking.
Breathable paint allows water vapour to escape, helping your walls dry out naturally rather than trapping it in the fabric of your home.
Why Breathable Paint Matters in Cellars
Because cellars sit below ground level, they are often cooler and more humid than the rest of the house. Standard plastic based paints like vinyl emulsions create a moisture barrier that traps damp inside the wall.
Over time, this can lead to mould growth on walls, paint failure, and poor indoor air quality. Breathable paints let the walls release moisture vapour, improving the health of the space.
See Also: Breathable paints for old houses | mould on painted walls | Best damp proof paint for walls
What Makes a Paint Breathable?
Breathable paints have a high vapour permeability. This means water vapour can pass through the paint layer rather than getting trapped behind it.
Natural paints, especially those based on lime or silicate, typically offer the best breathability. Look for paints with a low Sd value to ensure proper airflow through your walls.
Understanding Sd Values – How to Spot Genuine Breathable Paint
Not all paints that claim to be breathable actually are. The true measure of breathability is the Sd value, which relates to how easily water vapour can pass through the paint surface once dry. A lower Sd value means higher breathability, and a genuinely breathable paint should have an SD value of 0.5m or lower.
Be cautious of mainstream 'eco' or 'breathable' labels that don’t disclose vapour permeability data.
The Best Breathable Paint Options for Cellars
Choosing the right breathable paint for your cellar depends on how damp the space is and how much use the room gets. Here’s a breakdown of our top natural and mineral-based paints, based on substrate and traffic levels.
For Damp Cellars Prone to Mould
Auro 327 - A lime based, anti mould paint that performs well in low-traffic, damp-prone areas. If your cellar is musty or has experienced surface mould, this may be a good choice.
Graphenstone Ambient Pro - A high quality, air-purifying paint that offers excellent breathability, mould resistance, and durability. Ideal if you're turning the space into a more usable room and want the cleanest air environment possible.
For Low Traffic, Dry Cellars
Auro 321 - A simple, matt white natural emulsion. It’s breathable, very cost effective, and great for refreshing storage spaces where walls just need a clean finish.
Graphenstone Nevada - Another budget friendly mineral-based, breathable matt white paint for interior use.
For Cellars That See Regular Use
Auro 303 - The premium choice from the Auro range. Offers higher durability and breathability, making it a good pick if you use your cellar as a workspace or utility area.
Auro 524 - Slightly more robust again, ideal if you're expecting more wear and tear on the surfaces.
How to Prepare Cellar Walls Before Painting
Your paint is only as good as the surface you’ve applied it to, so make sure you do some prep even if nobody ever sees your cellar!
Remove any flaking or peeling paint with a scraper or stiff brush
Treat any visible mould with a natural mould remover like Auro 412 and mould growth retardant like Auro 413.
Allow damp walls to dry out as much as possible before painting
Apply a breathable mineral primer if the surface has previously been painted or sealed
Proper prep ensures your new paint can bond correctly and perform as intended, ensuring your cellar and home remain healthy.
FAQs
Is limewash good for basements? Yes, but only if your walls are bare masonry or lime plaster. Limewash is extremely breathable but may need regular reapplication.
What if my walls are already painted? You’ll need to use a breathable mineral primer first to create a suitable surface for your new paint to adhere to.
Let us know if you’d like help choosing the right paint for your cellar walls. We’re happy to offer advice based on the surface type and the condition of the space. Contact our team by phone or email for help with your cellar project.
