What is rising damp and what are the signs of a problem?

What is rising damp?

Rising damp occurs when excess moisture from the ground absorbs up into porous building materials such as stone, brick, earth, mortar and into the structure of the building. The moisture evaporates from either face of the wall, allowing more to be drawn from below. Rising damp is common in older buildings, but can also occur in more modern buildings if your damp-proof course has been damaged.

Though rising damp may cause unsightly aesthetic damage, it can also cause the structure of the building to be compromised and cause you bigger problems in the future. Damp walls also encourage mould growth, which can lead to health problems for occupants.

You can often identify rising damp by just looking at and touching your walls, though if you are unsure whether there is a real problem, it is best to have a water damage professional do an assessment.

What are the tell tale signs of rising damp?

There are a number of typical signs that can identify rising damp including:

TIDE MARKS AND DAMP STAINING

One of the most common signs of rising damp are tide marks left on walls. Tide marks are caused by evaporation and salts from the ground. You will usually notice them anywhere up to one metre above the skirting board.

If you do not notice tide marks, another frequent tell tale sign is damp patches or staining. usually, these damp patches are yellow to brown in colour and similar to tide marks, you will notice them again up to one metre above the skirting board.

PEELING WALLPAPER

If you’ve noticed wallpaper coming off or peeling from the wall there may be a damp issue. Usually the wallpaper will start coming loose from the skirting board first, and the corner of the wallpaper may be curved up.

DECAYED SKIRTING BOARDS

As with many forms of dampness, rising damp has the potential to cause rot within timbers it comes into contact with. Look out for skirtings that are cracked, easily crumble or localised fungus growing on or creeping out of the side. Also, look out for damaged or flaky paint.

SALTS WITHIN THE PLASTER

Fluffy deposits in the plaster are a sign of salts within the plaster. This is another sign of rising damp. These salts are washed out of your bricks and into your plaster leaving what can often look like blistering patches on your walls.

BLACK MOULD

If you start to notice black mould appearing above your skirting board it is a clear sign that there is some form of moisture issue affecting the area. This is especially true if you have no other black mould within the property and the black mould you see is localised from the skirting board to up to one metre above.

What are some other signs of rising damp?

If the above listed signs of rising damp don’t quite fit with the damp issue you’re experiencing, but you still suspect rising damp, start by running your hands around the suspected area. If you have wallpaper on your walls, you may hear a suspicious ‘crunching’ sound – this is the salts that have been drawn up from the ground. Then if possible, look at the exposed surface of the brick or stone work. Check to see if there are any salts forming and whether the brick is actually wet.

It is also important to note that rising damp only occurs on ground floor levels as it is moisture from the soil that is being drawn up the walls and therefore causing the rising damp problem.
If your damp problem is on the first floor or above, you may just simply have a condensation problem or a penetrating damp issue.

Identifying rising damp

Sometimes rising damp can be misdiagnosed. So if you are not sure and you want some expert advice, give us a call at Zephyr Ventilations. We can assess your moisture problem and give you the right specialised advice.