Can Ventilation Reduce Damp

Can Ventilation Reduce Damp

By Ruth MacEachern

Product Manager

It can be very worrying to discover a patch of damp in your home.  Damp in walls and ceilings can cause damage to the fabric of your property as well as creating the conditions for mould to thrive.  Damp and mould can be harmful to your health and cause severe difficulties for people with weaker immune systems such as young children and the elderly.  With this in mind, if you find damp in your home, it is important to deal with it quickly and prevent it returning.

Depending on the type of damp you have in your property, preventing the problem from recurring may require building work to be carried out, or improvements to your ventilation.

What causes damp

There are three main causes of damp found in UK homes, and they are named after the way the moisture is brought into the property.

• Penetrating damp
• Rising damp
• Condensation damp

Penetrating damp is caused by water leaking into walls or ceilings.  This water can come from a variety of different sources and fixing them will usually stop the problem.  A broken tile in your roof that is creating a leak; a crack in an exterior wall; a failed seal on a window frame; even a dripping radiator can all be a source of penetrating damp.  Once the source of the damp is identified and repaired, the damp itself can be treated to remove any damaged material.

Rising damp is often considered as a severe form of damp.  Rising damp is caused when there is no damp-proof course preventing moisture from being drawn up into your brick walls.  Rising damp is easy to spot in a home – it will only affect walls on the ground floor up to a height of about 1 metre above the ground.  To stop rising damp, a waterproof membrane or treatment will need to be added to walls above ground level to prevent the bricks from drawing water out of the ground.  This can sometimes be an expensive problem to fix.

The third type of damp is condensation damp, and unlike rising and penetrating damp which involve water from outside the property, condensation damp is caused by the activities of the residents of a house.

What is condensation damp

During the winter, you may often see beads of water on your windows.  This condensation forms during the night as the temperature drops.  The amount of water vapour that the air can hold changes with heat, and as it gets colder, the water vapour is released from the air to form droplets.  This is most noticeable on windows, but also occurs on other cold surfaces including walls.

On porous surfaces like walls, soft furnishings, and woodwork, condensation soaks through the surface and eventually saturates the underlying material.  Over time, the moisture will damage plaster and forms the perfect environment for mould growth which may damage your health.

The water vapour in the air comes from many activities in the house.  Cooking on a hob, opening a dishwasher when it is hot, bathing or showering, and drying clothes on radiators all release steam which contributes to the humidity of the home. 

Can ventilation help with damp

Improving the ventilation in your home will not address the causes of rising or penetrating damp because it has no impact on the way moisture is getting into your home, however better ventilation can stop condensation damp permanently.

By fitting modern extractor fans in the rooms with sources of water, you can reduce the amount of humidity.  The extractor fans draw the humid air out of the room and expel it outdoors.  The action of the fans creates negative air pressure in the room where the extractor fan is mounted and reduces the amount of water vapour that can escape into the rest of your home.

Reducing the amount of humidity in the air will reduce condensation throughout your home, particularly if you choose fans with built in moisture sensors that adjust their power level to address whatever moisture levels there are in the air.

Some homes with persistent condensation damp may benefit from the installation of whole house ventilation.  Positive Input Ventilation Systems (PIV) draw fresh air into your home continuously to displace humid air.  The air is drawn in at roof level and filtered to remove particles which also helps people with allergies.

Find out more

Could improved ventilation stop damp in your home?  If you are concerned about condensation or have noticed mould growth in your property, we can help.  Book a free home survey with our local ventilation specialists.  They will visit your property and identify the causes of condensation to be able to provide you with advice about the best solution for your needs.  Simply enter your postcode below to find an expert in your area.