Identifying problems with Damp - is it Condensation, Rising or Penetrating?

Damp is a serious problem affecting many households across the country. As well as being unsightly and damaging to buildings, damp can also lead to health issues such as asthma and a compromised immune system.

Furthermore, this even becomes detrimental to the value of your house and will often deter buyers from even considering your property as a viable option.

With so many issues surrounding damp, it is important to understand the different types and the causes behind each.

Armed with this information, homeowners can make the best decision on how to combat this problem.


Condensation is the most common cause of damp but fortunately, the easiest to remedy. Excess water vapour within the home can have a variety of causes, including poor ventilation, clothes drying, cooking and many other day to day activities.

The problem occurs when this water vapour has nowhere to go and condenses on cold surfaces, such as windows and walls.

It is for this reason that condensation tends to be a bigger issue in the winter.

Condensation can lead to the growth of black mould which can cause allergic reactions and breathing problems. The damp itself can cause damage to paint, wallpaper and even window fixtures.

Thankfully, there are many methods in which to combat the problem of condensation. Ventilation is paramount in preventing a build-up of water vapour within your home.

Any time you are carrying out activities such as cooking or washing clothing, try to ensure proper ventilation. This can include anything from the use of extractor fans to simply opening a window.

If you have a lot of condensation, it may be beneficial to invest in a dehumidifier that will actually remove the water vapour from the air.

In terms of window fixtures, plastic is better than wood as it is waterproof. However, if you have wooden window frames you can get around this by painting them with fungicidal paint in order to stop mould growth.

Penetrating Damp

Penetrating damp happens when water leaks into the house due to structural problems within the roof or guttering.

For example, a faulty or blocked gutter may not be transporting rainwater from the roof to the ground and therefore the water leaks into the interior walls.

Another contributing factor to penetrating damp is older brickwork which has become more porous and more likely to let moisture in. This type of damp can lead to mould growth and damage to your roof and wall structure. It goes without saying, this can have huge implications on your health and even your safety.

It can sometimes be difficult to distinguish between penetrating and rising damp but there are signs to look out for. Penetrating damp usually gets worse after a period of heavy rain, whereas rising damp is continuous. The damp patch itself is more likely to appear at the top of walls but can actually move around the building, in a horizontal pattern.

Fixing a penetrating damp problem involves checking your entire property for any problems. This means cleaning your gutters and possibly even replacing them, should the issue not resolve. You should also check your roof, paying special attention to flat roofs and insulation. Rendering is another issue to keep in mind as any cracks should be filled to prevent water from getting in.

Rising Damp

Rising damp is less common than condensation and penetrating damp but can be much more insidious and difficult to deal with. It is caused by brickwork and masonry absorbing water from the surrounding ground, leading to a build-up of water within the wall space.

Usually, there is something called a damp-proof course that prevents this from happening. This is a horizontal barrier made from plastic or slate, situated under the floor or within the walls which stops the moisture from getting past a certain point. If there is a problem with your damp-proof course, you don't have one, or if the exterior water is above it, then rising damp can occur.

Signs to look out for include a tide mark that covers the bottom half of your walls, mould growth and a general musty smell.

Rising damp can also cause a lot of damage to your home, degrading paint, wallpaper, floorboards and plaster.

If you suspect that your home doesn't have a damp-proof course, it's best to consult an expert and you may have to install damp-proof membranes or a full course in order to fix your problem.

You could also look into why so much water is entering you home. If the soil around your house is higher than your damp course, try digging it out to prevent water from entering at a higher point.

PIV - Positive Input Ventilation

Loft or surface-mounted PIV units are a great solution for condensation and mold problems. They introduce filtered air into your home forcing the damp air out.

Read more about PIV systems here

Buy Nuaire PIV Units here

Buy Vent Axia PIV Units here