18th Aug 2021

Painting over mildew
Aside from being unsightly, mould and mildew damages walls and can pose health problems to homeowners.

Unfortunately, mould is common in many houses, particularly on walls or ceilings exposed to moisture. The fungus usually appears as black or grey spots and they spread quickly, creating spores that can pose respiratory issues. Apart from breathing problems, they are known to cause allergies like headaches and fatigue. Luckily, it is easy to treat mould and mildew and restore the beautiful colour of a property. Here is a guide to assist painters in tackling mould and mildew in various houses.

Remove the Mould From the Surface

After identifying mould-infested areas in a property, most painters would opt to paint over the green or black patches. Unfortunately, paint products do not kill the fungus, and the patches will grow over the new coat of paint. First, identify the mould type and treat the hazardous and non-hazardous fungus separately. For hazardous fungus, find suitable detergents to remove mould and mildew.

Bleach is effective in eradicating mould patches from various surfaces. You can dilute the bleach with water and pour it on mildew-infested places to destroy the fungus and prevent further spread. However, you can use a stronger solution if you plan to repaint the surfaces.

When removing mould, avoid scraping it off when it is dry; it will release the spores and cause respiratory problems. Always moisten the surface to reduce the vaporisation of spores and use a microfiber cloth to trap any particles.

Prepare the Surface

After removing the mould and mildew from the surfaces, it is time to prepare the walls for painting. Find a combination shave hook or use a stripping knife to scrape off any flaky paint and crumbs. Brushing down or vacuuming the walls will ensure the crumbs, remaining mould particles and flaky paint do not ruin the new paint. You can also use abrasive/sandpaper to remove any paint and mould in corners and seams around the house.


Mould and mildew infestation eats through the walls and can leave rough patches. Porous drywalls and patches will soak up excess paint and the results can be uneven and will lack the sheen finish of the paint. If you want to conceal the existence of fungus, the appearance should be consistent on the walls. A primer can help you achieve shiny paintwork and remove any evidence of mould on surfaces. Besides, priming seals the patches on the drywall and the porous surfaces to prevent the soaking of paint. Even if you are painting over wood surfaces, ensure you have a suitable primer to seal off the fungus.

Choose the Right Paint for Mould and Mildew Prone Areas

Building walls are susceptible to mildew and mould growth. While you cannot solve all the issues, you can choose suitable paint. Some paints are more resistant to fungus by inhibiting their growth. Some brands have created specific paints for areas susceptible to mildews and mould and these products have anti-mildew formulations and chemicals to minimise fungal growth. You can also add mildewcide additives, which inhibit the growth of mildew patches to reinforce paint’s anti-mildew properties.

Apart from additives, you should go for less porous and glossy paints. They are not prone to mould and mildew growth since the fungus cannot stick to the glossy paintwork. Also, avoid paints made with linseed oil; it attracts fungal growth on surfaces. You can also advise homeowners to paint walls that are susceptible to mildew with dark colours. Darker shades dry faster after exposure to moisture compared to brighter colours which reflect sunlight.

Repainting the Walls

When the walls are dry and clean, you can paint the walls with oil-based or water-based paint. While one coat of paint will cover the areas affected by mould, you should apply two coats to remove any evidence of fungal growth. The mildew-resistant paint will also reduce maintenance after painting.


Mould and mildew can be a menace that makes a house look old and ugly. Besides, it can cost homeowners lots of cash in buying new paint to redo the affected areas. However, professionals can relieve them of the burden by using the above tips to handle mildew and mould. Destroying the fungus prevents future growth on the surfaces. Moreover, the mild-dew resistant paint can reduce the maintenance required for walls and ceilings and make the newly painted surfaces look shiny for an extended period.

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