Can you remove mould yourself?

When you can do it yourself

There are cases where calling a specialist really is not necessary, and we say so plainly. You can deal with it yourself if all of these apply:

• the patch is small — roughly up to the size of your palm;
• the surface is smooth and non-porous — tiles, painted wall, glass, plastic;
• it appeared recently and for the first time;
• you know the cause and can deal with it (for instance the extract was not working, or the room was rarely aired);
• there are no small children or people with respiratory conditions in the household.

If even one of these does not apply, doing it yourself usually amounts to postponement rather than a solution.

What to check before you do anything

Before buying a product it is worth establishing two facts that change everything that follows: how humid the air is and whether the ventilation works. Both checks cost close to nothing.

• Hold a thin sheet of paper against the ventilation grilles in the kitchen and bathroom. If it does not stick, the extract is not working.
• Buy a hygrometer and measure the humidity in several rooms over several days in a row.
• Check whether there is a gap under the bathroom door — without an air supply the extract will not work even with a clean duct.
• Move furniture away from external walls and look at the wall behind it.
• Wipe a small part of the patch, note the date and see whether and how quickly it comes back.

The last check is the most important, because it answers the main question. If the patch does not return for months after cleaning, you really did deal with it. If it comes back within weeks, the moisture source is still there, and no product will change that.

When you cannot

• A porous surface — wallpaper, plasterboard, plaster, timber, insulation. The fungus grows inside the material, and surface treatment does not reach it.
• The patch comes back — meaning the cause has not been dealt with, and another round of cleaning will change nothing.
• A large area — more than roughly half a metre.
• The cause is not clear — without a measurement there is no way to know whether it is condensation or a leak.
• A smell with no visible patch — the fungus is somewhere you cannot see.
• After flooding — there is water in the structure, and it has to be dried out first.

The porous material limit is the one most often crossed by people working on their own. Wallpaper with fungus cannot be treated — the fungus grows both in the paper and in the adhesive layer beneath it. A plasterboard sheet with a dark patch means the paper facing is a food source, and its core holds moisture long after the surface is dry. In both cases the material has to be removed, and that is no longer a question of which product to buy.

What actually works, and what does not

The most important thing to know about shop-bought products: their job is to treat the surface. None of them is intended for fungus that has grown into the material, and none of them changes why the material is damp.

Bleach deserves a separate note, because it is the most common home remedy. On a smooth surface it works. On a porous one it mostly bleaches — after a few hours the patch looks as if it has gone, but the fungus in the material has stayed and will return. People then conclude that "mould is very stubborn", when in fact it was never removed.

The most common mistakes

Two of these mistakes cost more than the rest. The first is painting over: the paint hides the patch for a few months, the fungus underneath keeps growing, and in the end both the paint and what is under it have to come off. The second is treating a wall that is still wet after flooding — that is money entirely wasted, because treatment does not work in wet material.

What changes the price if you do call us

The price range for mould work is wide, not because it is vague but because the scope of work varies by a factor of several.

Prices

If after reading this page you conclude the case is within your own capability — good, that was the point. If not: inspection with moisture readings from €40, treatment from €1.50/m², minimum from €80.