Did you know that there are thousands of mould remover sprays on the market, with the majority of cleaning products containing bleach? When you visit your local supermarket, you are guaranteed to find a mould spray in the household cleaning aisle, with statements such as “Removes 100% of Black Mould”. However, the effectiveness of killing mould on surfaces with bleach is often misunderstood. If you’re looking for reliable and practical advice, our damp and mould specialists are here to cut through the common myths.
Do Not Spray Mould, Spray the Cloth
Spraying bleach or any mould spray directly onto a mould patch might feel like the right step, but it can actually make the problem worse. Applying bleach directly as an anti-mould remover spray can spread fine spores into the air, increasing the risk of inhalation and allowing spores to settle deeper into fabrics and porous surfaces.
Instead, dampen a cloth with your chosen cleaner and wipe the area gently. This reduces airborne spores and helps remove visible mould more safely.
Why is Bleach Commonly Used for Mould?
Bleach is often used as a black mould remover because it is a powerful disinfectant. On hard surfaces like tiles and bathtubs, bleach can kill visible mould and remove surface staining quickly.
People also choose bleach because it’s a widely available and affordable household cleaning product. But familiarity does not always translate to effectiveness.
How Bleach Reacts With Mould on Non-Porous Surfaces
Bleach can be effective on non-porous surfaces such as glass, ceramic tiles, sealed countertops and metal. On these materials, the bleach solution stays on the surface and breaks down mould cells, helping to kill them and lighten surface stains.
However, your success depends on how you use it. Let cloths soaked in the bleach solution rest on the affected area rather than spraying directly. This maximises contact with the mould without splashing chemicals around the room.
Limitations of Bleach on Porous Materials
On porous materials such as wood, plaster and fabric, bleach has a major limitation. It does not penetrate below the surface. When bleach only sits on the surface, it may remove visible colour but the underlying mould can stay alive, hidden deep within the material. This is why you might notice mould returning after cleaning, even when you’ve used a strong mould remover spray for walls.
David Bly, Cornerstone’s Managing Director, shares his views on why household solutions often fail to deal with mould effectively:
“They don’t have the bio or fungicidal elements in them necessary to deal with the mycelium. Bleach-related products can deliver a very clean surface and, as mould is a visual detriment, it is believed the problem is solved post this undertaking!”
Why Mould Often Returns After Bleach Treatment
If mould comes back shortly after treatment, that’s not unusual. Since bleach doesn’t reach the mould roots inside porous materials, the visible mould may be removed while the hidden colony survives and regrows.
David, Cornerstone’s damp and mould specialist, explains why mould problems return after cleaning:
“Mould has a root system (mycelium) and the use of bleach-related products does not deal with the roots. In the absence of dealing with the root causes, the growth will return in a shorter timeline.”
Without addressing the cause, such as damp, poor ventilation or even hidden leaks, mould will almost always return, regardless of what black mould remover you use.
When Professional Mould Treatment Is Recommended
If mould covers a large area, returns quickly after cleaning or keeps coming back despite regular cleaning, it may be a sign of an underlying damp or ventilation issue. Mould specialists, such as Cornerstone, can:
- Identify the source of moisture.
- Treat mould inside walls and cavities.
- Recommend long-term prevention methods.
Professional intervention is especially important for health-sensitive environments. Don’t rely on short-term fixes. Get professional advice you can trust! Contact Cornerstone today for a specialist damp and mould assessment and take the first step towards a healthier, mould-free property.
