Why Do My Interior Walls Have Damp Patches?

Why Do My Interior Walls Have Damp Patches?

Do you have damp patches on your interior walls? If so, there are many reasons why this may be happening. Here we explore some of the most common causes and how to fix them.


If your home is regularly over-heating, this may cause your exterior walls to fog up, without you even noticing. This can then seep into the internal wall cavities and leave internal damp patches on walls. To eliminate this issue, make sure that your heating system has been adjusted to meet the current needs of your home (if not, call out an HVAC professional).

The air conditioner is too strong or too close to the wall

The air conditioning is working fine, but you are experiencing a moist or damp spot because your home has an unusual amount of humidity. This is caused by the evaporative barrier being washed away by the large amounts of dew that occur in your particular environment. If this is not under control, look for a humidifier for your home to help regulate humidity levels naturally.

A leaking pipe

There are many different scenarios that could cause a leak, but a few of the more common ones include:

Excess water traveling into your walls from sprinkler systems and roof leaks

Water under pressure from broken pipes or faucets that may have been neglected and have now burst their way through the barrier

Fungal growth in your basement

As some fungi feed on moisture, fungal growth may be severe in very damp climates. This can cause damp patches to appear on ceilings and floors in your basement.

In order to eliminate the damp, cut out the fungus and dry the area by opening windows or running fans. To prevent any future occurrences, make sure that there is no standing water in your basement.

basement tanking

A humidifier is too close

If you have ever experienced a pet getting sick after having a lick of wet carpet, you may have discovered that keeping your house too warm can cause significant humidity issues. If this is occurring in your home it could be because of moisture from a nearby humidifier. You should try to keep a reasonable distance between your humidifier and other objects, as this will help prevent any moisture build-up.

Radiators and plumbing stacks

In certain homes, radiators can overheat and cause water leaks, which could possibly lead to damp patches on your walls. To fix this issue you may need to upgrade the radiator valves or the radiator itself.

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