Mould on skirting boards? Why it happens and how to get rid of it

Mould on skirting boards is not only unsightly but it usually points to a bigger issue. If mould is left unresolved, it can have health implications and the cause could damage your home.

Thankfully, there are steps you can take to prevent, treat and cure this problem and removing mould from walls once the issue has been dealt with should not be too troublesome either. 

There are a couple of reasons why you might be finding mould on your skirting boards and in this handy guide we will be explaining what might be causing it to appear in your home as well as giving you tips and advice on how to resolve the issue once and for all. 

What causes mould on skirting boards?

There are usually two main culprits when it comes to mould forming on skirting boards and walls: condensation and damp. 

Although condensation as a cause is most likely in bathrooms and kitchens, where there are usually high levels of humidity, in poorly ventilated homes, condensation can become problematic in pretty much any space.

Where damp is the cause, things can be a little more complicated. Before the mould can be fully resolved, it will be necessary to first understand what causes damp and, secondly, to get to the bottom of what the underlying reason might be. Then, you can work out the best solution. 

In either case, both excess condensation and damp can, if left unchecked, lead to skirting boards that twist, warp and come away from the walls. They may also rot. This is a particular problem for those with MDF skirting boards and if not remedied quickly, you may end up needing to replace them, which is not always a quick or easy job.

How do I stop mould from condensation?

If you have a condensation problem then you are going to know about it. Droplets of water or little streams of water running down walls and windows are both sure signs.  

So, how to solve condensation? There are several ways you can stop this pesky problem and once the condensation is dealt with there should be no more mould to contend with.

"If condensation is the primary cause – typically in bathrooms and kitchens – then the solution is pretty simple," reassures Homebuilding & Renovating's DIY content editor Steve Jenkins. "Good home ventilation is vital. Open windows to let air circulate or switch on an extraction fan. If you don’t have one, think of getting one installed."

You can take a look at some of the best bathroom extractor fans on the market at the moment in our guide.

"Cold floors can attract condensation as warm moist air and steam condenses, particularly in kitchens and bathrooms," says chartered surveyor Ian Rock. "To deal with condensation, new extractor fans can help disperse humid air and improve ventilation. A less cold surface covering, such as wood flooring, can be placed over a layer of rigid insulation material to make the surface warmer."

You could also think about investing in a dehumidifier, like this 12 litre one for £184.99 from Elecci on Amazon. These remove excess moisture from the air before expelling dry air back into the room at a slightly warmer temperature. They are also great for getting wet washing dry faster. 

Does damp cause mould on skirting boards?

Dealing with mould issues caused by damp is a little more complicated because before you can select the correct remedy, you first need to find out where the damp is coming from. 

In some cases, the damp problem could be fairly easy to put right. If, for example, your damp is the result of leaking rainwater goods, blocked gutters or due to water getting behind bathroom tiles, simply mending these faulty features should fix the issue.

If there are no obvious causes, it will be necessary to dig a little deeper to find out how to treat damp in your home. If you live in an old house, it may well be that modern 'improvements' are the cause of your woes. 

"Nowadays the majority of cases of damp in period houses are caused by inappropriate building work that stops moisture escaping," explains surveyor and damp consultant David Kinsey. "With older solid walls it is advisable to remove incompatible modern materials such as cement render or mortar pointing that trap damp. Replace with traditional lime-based breathable materials that allow moisture to evaporate."

In the case of mould on skirting boards, the problem may well be originating in the floor. 

"Floors become damp where the evaporation of moisture from below is inhibited by vinyl sheet, rubber-backed carpets or other impervious coverings," explains David Kinsey. "New concrete floors or impervious coverings also drive excess moisture into the bases of nearby walls, where it rises by capillary action."

Of course there are other sources of damp that you should also be aware of. 

"Leaks from defective plumbing are a common cause of damp," says Ian Rock. "Copper pipes, such as those serving radiators, embedded in concrete floors are very prone to corrosion and leakage unless protected with tape or run within ducts. 

"To allow damp floors to dry out naturally, remove carpets and floor coverings. Once exposed it can take several weeks for floors to fully dry out."

If all other avenues have been explored, it will be well worth looking at improving the breathability of your floors.

"In old homes, solid floors laid on bare soil need to ‘breathe’ so any moisture can evaporate," explains Ian. "Smothering them with impermeable floor coverings, such as vinyl, will trap this ‘perspiration’. Ideally such covering should be replaced with a natural breathable floor, or quarry tiles bedded in lime mortar should be reinstated."

Finally check that your external ground levels are at least 200mm lower than the indoor floor level or Damp Proof Course (the black sheeting between lower brickwork). They should also slope away from the walls to allow surface water to run away from the walls of the house.

How do I remove mould from skirting boards?

Once you have got to the bottom of what is causing the mould and are sure the problem is not going to return, removing it should not be too difficult. 

There are several methods you can use to remove mould from skirting boards.

One of the best is to simply use a solution of warm water and washing up liquid, wiping off what you can with a sponge, cloth or scourer before drying the surface off with an old cloth or kitchen roll. You can then use a mixture of one part white vinegar mixed with one part water, spraying it onto the skirting boards. Leave it to get to work for around an hour then use a scourer to remove and dry off. Meanwhile Homebuilding's Amy Willis rates HG mould spray as the most effective mould removal product, which she tried out on mould on her bathroom ceiling along with a couple of other household products.

Alternatively, Steve Jenkins suggests using a paste made up from two parts baking soda to one part white vinegar. He recommends applying the paste to the mould and leaving it for around an hour. 

"For your safety put on rubber gloves and a face mask," says Steve. "Use a stiff brush to remove as much of the paste as possible. If needed use a kitchen sponge/scourer to get rid of any residue. Wipe down the area with a damp cloth. To help make sure that all the mould spores have been killed off, finish by spraying the affected area with a fine mist of water and vinegar and leave to dry."

Once you have removed all traces of the mould it is very likely that you will need to repaint your skirting boards — thankfully, there are ways of painting over mould that will leave your skirting boards as good as new. 

If the problem was really bad and your skirting boards had become badly damaged or come away from the wall, you will obviously need to buy and fit new skirting.