Do anti-mould paints really work?

They significantly delay mould growth but don't replace identifying and treating the moisture source.

How is a mouldy wall prepared?

Remove mould with a suitable fungicide, dry the surface, apply anti-mould primer then paint.

Anti-Mould Paints

Black spots on the bathroom ceiling or in the corners of north-facing walls - every homeowner's nightmare. Mould doesn't just ruin aesthetics; it's a serious health risk, especially for allergy and asthma sufferers. In this guide we cover everything from chemical composition to correct application.

What They Do, What They DON'T - and the 3 Categories

Infographic: What they do (prevent, protect film) vs what they don't (don't kill existing mould, don't fix structural issues)

The biggest misconception: anti-mould paint is not a magic filter that eliminates damp problems.

✓ Prevent New Mould

Special additives make the wall surface "hostile" to fungal spores - blocking new mould from forming.

✓ Protect the Paint Film

Keep the coating spotless in rooms with occasional high humidity (bathroom after a shower, kitchen steam).

✗ Don't "Kill" Existing Mould

Painting over a black spot? The mould feeds under the film and will soon peel it off.

✗ Don't Fix Structural Problems

Broken pipe, roof leak, rising damp? No paint will save you - they work surface-level only.

The 3 Categories & Primer vs Paint

Not all "anti-mould" paints are the same - three entirely different approaches:

Infographic: 3 categories - Chemical, Thermo-ceramic, Silicate + Primer vs Paint

A. Conventional (Chemical)

Acrylics with biocides/fungicides. They poison spores on contact. Ideal for domestic bathrooms.

B. Anti-Condensation (Thermo-ceramic)

Microscopic glass bubbles = light insulation. Keep the wall warmer → no condensation → no mould.

C. Silicate (Mineral) Paints

Potassium silicate = high pH. Fungi can't survive in alkaline environments. No biocides, maximum breathability (Sd < 0.05m).

Primer vs Paint

Primer: penetrates deep, kills "roots." Paint: hard surface shield. In "tough" rooms, the combination is the only sure solution.

The 4 Steps to Correct Application

Infographic: 4 steps - clean, dry, prime, topcoat

Preparation is everything - if you just open the tin and paint straight away, you'll fail:

Step 1: Clean & Disinfect

Gloves + mask. Bleach solution (1:3) or biocide wash. Never dry-sand live mould - you'll scatter spores everywhere.

Step 2: 100% Dry

Trapped moisture = destruction of the new coat. Wait until the wall is completely dry.

Step 3: Anti-Mould Primer

One coat of anti-mould primer - penetrates deep into pores, seals and kills the "roots."

Step 4: 2× Topcoat

Two coats of quality anti-mould paint (Kitchen & Bath) - tough, washable film.

Technical Corner: Standards & Chemistry

For engineers and professionals - the standards and chemistry behind anti-mould coatings:

Infographic: EN 15457, Zinc Pyrithione, Ag⁺, Sd value

Parameter	Description	Why It Matters
EN 15457	Standard for testing film preservatives against fungi	Proves biostatic/biocidal action (Class 0–1)
Zinc Pyrithione (ZnP)	Broad antimicrobial spectrum - replaces isothiazolinones	New generation, fewer allergens
Silver ions (Ag⁺)	Embedded in nanoclays - destroy bacterial DNA	No microbial resistance development
Sd Value (Breathability)	Silicates: Sd < 0.05m → maximum MVT	Prevents moisture trapping behind film

Conclusion

Choosing the right anti-mould system requires diagnosis. Poor ventilation? Conventional or anti-condensation. Historic building with trapped moisture? Silicate. Remember: paint is the last line of defence - good ventilation and no leaks come first.