How Can I Prevent Damp In My Home?

What is damp?

In homes, damp patches form when excess moisture is allowed to build up in porous materials such as plaster walls and bricks.  If damp is allowed to build up in your home you may start to notice mould growing on walls, as well as seeing crumbling plaster and peeling paint.

Damp problems often tend to get worse in winter when cold temperatures make it harder for moisture to evaporate naturally, but in some homes, damp can be an issue all year round.

The first sign of damp might be a discoloured patch on a wall or ceiling, but over time, as mould starts to colonise the damp area, you may start to experience a musty smell around your property and may suffer from some allergic reactions from mould spores and mycotoxins spreading in the air.

Rising damp

Rising damp is often seen in older properties.  It is caused when moisture from the ground is drawn up into the walls.  Since 1875, most homes have been built with a damp proof course at the bottom of the walls – in modern homes, this is a plastic membrane that prevents water from soaking above ground level.

Statistics from the English House Condition Survey found that around 11% of homes built between 1900 and 1918 have the presence of rising damp and around 1% % of houses built after 1956 are also affected.

Rising damp only happens at ground floor levels as the moisture drawn up the wall comes from the soil in the ground. It is often confused with damp caused by condensation.   If you have discoloured patches up to about 1 metre above ground level in your home, or have noticed decaying skirting boards around exterior walls, your property may be affected by rising damp.

Preventing rising damp

Keeping on top of your home maintenance is the best way to avoid rising damp in your home.  The following will help prevent rising damp:

• Use an electronic moisture meter (which you can find in most DIY shops) to check the moisture levels in the walls twice a year.
• Ensure that the ground level outside your home is below the damp proof layer in the wall.  Dig away soil that is resting directly against the outside walls  of your home to leave a gap and prevent moisture from bridging the gap/

Rising damp is easy to spot but it is often confused with condensation damp. Condensation damp is easier to remedy and not as expensive to fix.

Condensation damp

Condensation forms on cold surfaces when warm air comes into contact with them.  High humidity levels found in “wet” rooms such as bathrooms and kitchens are the main cause of condensation in homes.

If the droplets of water that make up condensation are not removed from porous surfaces such as walls and ceilings, they can soak in to form damp patches.

Damp from condensation can occur anywhere in your home.  As the water is soaking in from the front of the wall, it does not always cause discolouration of your paintwork, however surface level damp can quickly be colonised by mould and you may start to see patches of black mould on walls or around window frames where damp has soaked in.

Preventing condensation damp

Improving the ventilation in your home is the most effective way to stop condensation damp from becoming a problem.

Fitting or updating extractor fans in your bathroom or kitchen helps to remove the humidity in the air at source to prevent it escaping into other rooms.  Modern extractor fans often include a humidity sensor that can detect moisture levels and automatically adjust power levels to clear the water vapour in the air more quickly.

If your home has condensation problems away from an obvious source of moisture, whole house ventilation such as Positive Input Ventilation (PIV) may be the best solution.

Stopping damp and mould

It is vital that you keep on top of home maintenance, especially on the exterior of your property because prevention is better than cure when it comes to damp problems. Check your roof regularly for damage, especially after stormy weather. Keep gutters clear and fix or replace as soon as any damage occurs.

During colder periods, it is important to keep your home warm.  Condensation forms when warm, moist air touches a cold surface like a chilly windowpane or a cold external wall. Loft and wall insulation can help create warmer spaces, and properly fitted double-glazing will help to avoid misty windows as the inner panel of glass is insulated against the cold air outdoors.

Be mindful of the amount of steam created when cooking on the hob.  Ensure that you use a lid on pans when using the stove and avoid opening the oven too often as this can release large quantities of steam that will quickly form condensation.  Use the extractor fan in your cooker hood both during and after cooking and ensure that you have a suitable extractor fan in the room.

When the weather is good it's a great idea to open the windows in your home to allow air movement and provide a way for excess moisture to escape. 

Choose moisture resistant paint and wallpaper - If your home is prone to damp or condensation, choose wall finishes that make problem prevention easier. Opt for painted surfaces and choose paints designed for use in kitchens and bathrooms. With formulas designed to resist moisture and steam, they’ll not only help to keep mould at bay, but will also wipe clean more easily if any mould develops.

Leave room for air to flow around large items of furniture.  Try to position furniture a few centimetres away from external walls, to allow air to circulate and prevent mould problems from developing. 

Good ventilation will help minimise condensation and stop if from forming damp.  Giving moisture a route to escape your home will help reduce humidity and stop reduce condensation related damp. 

One way to prevent condensation damp is to have a whole house ventilation system fitted in your loft space or hallway to ventilate your home.

EnviroVent has a range of ventilation systems designed to prevent condensation and mould problems. By fitting a whole house ventilation system and correctly ventilating your home, condensation dampness will disappear and your damp areas will dry out, ready for redecoration.