# Anti-damp and anti-mould paint: does it work? What it promises and what the sheets say

> Tin promises against data sheets, warranty terms and the biocides regulation: the paint can help the finish, but it does not correct the cause of the damp.

- Page: https://paredecerta.pt/en/guides/anti-damp-anti-mould-paint-does-it-work
- Language: English
- Updated: 2026-11-03

## Summary

- The data sheets we read tell you to identify and remove the cause of the damp before painting.
- The terms of Robbiotel's 10-year warranty exclude fungi and blistering where there is capillary rise or leaks.
- "Anti-fungal" means protecting the paint film with biocides, not treating the wall. The EU regulation requires active substances to be labelled.
- Paint can improve the finish once the cause is fixed. On its own it does not solve damp or mould.

Tins say "anti-damp", "anti-fungal", "anti-condensation". This guide sets those promises against what the data sheets, warranty terms and regulations actually say, and asks: does a paint like this fix a damp or mouldy wall? Short answer: it can help the finish, but it does not correct the cause. We do not compare brands and we did not test any product.

*Updated 3 November 2026. General information, not a substitute for a technician's assessment.*

## The essentials

- **The data sheets themselves say to fix the cause first.** Dyrup writes: "before using the product, identify the source of the damp and eliminate it".
- **Robbialac's warranty excludes the most common case.** The terms of the 10-year Robbiotel warranty exclude fungi and blistering where water rises by capillarity or leaks in.
- **"Anti-fungal" means protecting the paint film,** not killing the mould in the wall or drying it.
- **The Swiss federal public health office opposes paints with biocides in living areas,** because long-term risks are hard to assess. The US EPA says paint over mould tends to peel.
- **Never paint over mould** as a fix. See [mould on walls](https://paredecerta.pt/en/guides/mould-on-walls).

## Promise and small print

| Product (sheet) | What it promises | What the sheet or terms add |
|---|---|---|
| Anti-Humidade (Dyrup, April 2020) | "Barrier to water infiltration"; removes stains; reduces the chance of salts | Do not apply above 20% substrate moisture or on wet surfaces. For counter-pressure leaks or basements, waterproof from outside first |
| Robbiotel Acetinado (Robbialac) | "Prevents and solves fungus or damp-stain problems" | The sheet asks for 5% bleach or the brand's disinfectant and a 24 h wait. It admits that painting fungus-affected walls "is always a hard problem to solve" |
| Cozinhas e Casas de Banho (Barbot, Rev. 08) | "Reduces condensation forming on surfaces" | Substrate moisture below 5%. In fungus-prone rooms, add the brand's anti-fungal additive |
| Dyrustop Fungi (Dyrup, May 2020) | "Effective protection against fungi" | Add to every coat. Without ventilation and lower humidity, "fungi may return" |

The sheets do not explain how substrate moisture is measured, so Dyrup's 20% cannot be compared with Barbot's 5%.

## What Robbiotel's 10-year warranty says

The warranty extension terms (read in full) show what a maker will accept to promise:

- Covers blistering, cracking, loss of adhesion, fungi and surface-condensation stains on the film.
- **Express exceptions:** blistering caused by water infiltration and damp in the substrate, and fungi where there is "capillary rise, leaks in the substrate or singular points".
- Does not cover zones of permanent condensation, such as indoor pools, spas or saunas.
- The warranty must be activated within 30 days and each defect reported within 30 days. It applies to buyers of up to 10 litres per job.
- The maker pays for the product and budgeted labour, but only a share: 100% in year 1, 40% in year 5, 10% in years 9 and 10. Scaffolding is not covered.

We found no equivalent warranty in the Dyrup and Barbot sheets we read.

## What "anti-fungal" on the tin means

**Film preservatives.** Sheets such as Vinylmatt (CIN) quote laboratory tests: grade 0 at 7, 14 and 21 days (EN 15457 for fungi). A lab test measures new paint film, not a damp wall.

**Biocides.** Regulation (EU) No 528/2012 requires authorisation to market and use biocides (Article 17(1)). It defines type 6 (in-can preservatives, to extend a product's shelf life), type 7 (film preservatives, to protect "paints", among others, against microbes and algae) and type 10 (construction materials). When a maker claims an article has biocidal properties, Article 58(3) requires the label to say it contains biocides and to name the active substances.

That is why the Robbiotel page in the brand's shop says "contains biocidal products", names dry-film preservatives (octhilinone and terbutryn) and warns of a possible skin allergy (H317).

**Tests that are not about mould.** Robbiotel states over 99.9% "antibacterial action" (ISO 22196). That is a bacteria test. The fungus test on the same sheet is ASTM D 5590, result "complies".

## Cleaning before painting: the sheets disagree

- **Robbialac:** 5% bleach, several rinses, the brand's aqueous disinfectant, 24 h.
- **CIN (Artibiose):** do not use bleach. Do not apply if bleach was used in the previous 20 days. Two applications of 5 to 6 hours each, then 24 to 48 hours drying.
- **Barbot:** the brand's cleaning solution.

Follow the sheet of the system you choose and do not mix brands. Ventilate and protect skin and eyes. The Swiss and EPA cleaning guidance is in [mould on walls](https://paredecerta.pt/en/guides/mould-on-walls).

## Why paint does not correct the cause

Paint can give a tougher finish and, in some cases, let vapour pass (Robbiotel states sd 0.14 to 1.4 m). It cannot:

- stop water rising from the ground or entering through a leak ([three types of damp](https://paredecerta.pt/en/guides/damp-walls-three-types), [leak from upstairs](https://paredecerta.pt/en/guides/leak-from-upstairs-who-pays));
- remove the salts that keep returning ([salt on walls](https://paredecerta.pt/en/guides/salt-on-walls-efflorescence));
- replace ventilation and heating where the problem is condensation.

Dyrup notes that walls painted with the additive need regular ventilation and dehumidification. If the film is already failing, see [peeling paint, blisters and stains](https://paredecerta.pt/en/guides/peeling-paint-stains).

## When it can make sense

Once the cause is fixed, the wall is dry and the mould removed, a paint with film protection can be a reasonable choice in a bathroom. See [which paint for each room](https://paredecerta.pt/en/guides/which-paint-for-each-room). Ask the seller in writing what the warranty excludes.

## What we could not confirm

- **How well anti-damp paints work on a real wall.** We only have maker statements. We found no independent test.
- **What "substrate moisture" means in the sheets** (method and unit).
- **Whether the preservatives named are approved today for this use.** We read the regulation, not the approved-substance lists.
- **Dyrup's data sheet for an anti-mould paint.** We read the Dyrustop Fungi additive.
- **DGS guidance** on anti-mould paint. We found none.
- **Prices and durability.** No reliable source.

## Sources (read on 3 November 2026)

- PPG Dyrup, [Anti-Humidade, ITC 1029](https://dyrup.pt/kentico/getmedia/239678e1-7a1a-49f5-9a7c-27f4a6f1170f/Ficha-tecnica_Anti-Humidade.pdf), April 2020 (in full).
- PPG Dyrup, [Dyrustop Fungi, ITC 1007](https://dyrup.pt/kentico/getmedia/74be9be4-f071-4e93-a77f-ec44f59ec684/Ficha-tecnica_Dyrustop-Fungi.pdf), May 2020 (in full).
- Robbialac, [Robbiotel Acetinado data sheet CC 032 24.1](https://cromoblobacc.blob.core.windows.net/cromoblobbucket/production/products/files/ROB_025/technical_data_sheet_pdf/pt_PT/025_Robbiotel_Acetinado.pdf) and [Termos e Condições de Extensão de Garantia Robbiotel](https://cromoblobacc.blob.core.windows.net/cromoblobbucket/production/products/files/TermoseCondi__esGarantiaRobbiotel/variation_scopable/web/Termos_e_Condicoes_Garantia_Robbiotel.pdf) (in full), and the [product page in the Robbialac shop](https://loja.tintasrobbialac.pt/pt/robbialac/robbiotel-aquoso-acetinado_p1168.html) (safety information).
- Barbot, [1601 Cozinhas e Casas de Banho](https://barbot.pt/wp-content/uploads/2024/01/1601-FT-COZINHAS-E-CASAS-DE-BANHO-Rev.-5.pdf), Rev. 08, 29/11/2024.
- CIN, [Artibiose 18-230](https://idoctec.cin.com/Home/Document/18230-DEC-CIN-BT-PT), rev. August 2026, and [Vinylmatt 10-250](https://idoctec.cin.com/Home/Document/10250-DEC-CIN-BT-PT), rev. July 2026.
- European Union, [Regulation (EU) No 528/2012](https://eur-lex.europa.eu/eli/reg/2012/528/oj/por) (Articles 17 and 58, Annex V). EUR-Lex would not open for us: we read the Spanish version of the Official Journal (L 167, 27.6.2012) and translated.
- Swiss Federal Office of Public Health (FOPH), [Mould in living spaces](https://res.cloudinary.com/adminch/image/private/s--IEfWBxCL--/v1719952980/Bundespublikationen/311_311_por.pdf), Portuguese version, February 2021.
- U.S. Environmental Protection Agency, [A Brief Guide to Mold, Moisture and Your Home](https://www.epa.gov/mold/brief-guide-mold-moisture-and-your-home).

## FAQ

### Does anti-damp paint solve damp in the wall?

It does not correct the cause. Dyrup's sheet says to identify the source of the damp and eliminate it before applying.

### Does the 10-year warranty cover mould that comes back?

Not where there is capillary rise or leaks. Robbiotel's terms expressly exclude those cases.

### Can I use anti-mould paint over mould?

No. The EPA says paint over mould tends to peel, and the Swiss FOPH does not regard it as a correct repair.

### What do the biocides on the label mean?

They are film preservatives, regulated by Regulation (EU) 528/2012. The label must name the active substances when biocidal action is advertised.

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Source: https://paredecerta.pt/en/guides/anti-damp-anti-mould-paint-does-it-work. Independent information, not legal or tax advice.