Damp or Mould: Knowing the Difference

rising damp sussex, damp or mould

If you have damp or mould the first thing to do is find the cause. Damp and mould can affect your health, so it’s important to get rid of it soon.

Usually, it’s caused by excess moisture, which can result from leaking pipes, rising damp in basements or ground floors, or rain seeping in because of damage to the roof or window frames.

In a newly-built home, damp can occur if the water used when the house was built is still drying out.

A common place for mould to grow in your home is the bathroom.

The causes of this are lingering moisture caused by lack of ventilation, leaky toilets, sinks and plumping pipes and damp cellulose materials such as rugs, paper products, wood, wallpaper, grout, drywall and fabric.

How Can It Affect Your Health?

According to NHS Choices, damp and mould in the home can cause respiratory problems, infections, allergies and asthma, and it can also affect the immune system.

Inhaling or touching mould spores can cause three types of symptoms:

Allergic reactions are the most common.

Mould infections can occur when mould spores are breathed into the body, allowing mould to grow inside them.

There are a few dozen moulds that are particularly toxic to humans, and these moulds release highly toxic chemicals called mycotoxins.

In order for intoxication to occur by these toxic moulds, significant quantities are needed to intoxicate.

Knowing the Difference

Each needs to be treated in different ways, and damp repair costs can vary dramatically, so it’s important to know what type of damp is affecting your home before you try to get it fixed.


Condensation is the most common kind of damp. It is caused by moist air condensing on walls, particularly in rooms with a lot of air moisture, such as kitchens and bathrooms. It’s mainly, but not always, a winter problem, as at this time of year walls are much colder than the air inside.

You may notice water droplets on windows or walls, see dark mould appearing, particularly on glass or around windows, and/or notice an unpleasant smell.  If left untreated, condensation can damage paint and plaster and cause window frames to decay, so when you see it form you should wipe it away with a cloth.

Rising Damp

Rising damp is caused by ground water moving up through a wall or floor. Most walls and floors allow some water in, but it’s usually stopped from causing damage by a barrier called a damp-proof course or damp-proof membrane.

If you have rising damp, you may notice damaged skirting boards or plaster, as well as peeling paint and wallpaper, often with wet patches. Rising damp may dissolve soluble salts from the ground and building materials, which can then crystallise, forming a white, powder-like substance. This, along with the water, can leave tide marks along the wall.

Archers can help with your rising damp, so get in touch with us today for safe and quick removal of your problem.

Penetrating Damp

Penetrating damp is caused by water leaking through walls. This type of damp may expand across your walls or ceiling, but this will move horizontally, rather than by travelling up walls (as is the case with rising damp).

Penetrating damp is usually caused by structural problems in a building, such as faulty guttering or roofing, or cracks in the walls, which mean walls or roofs are regularly soaked with water. It can also be caused by internal leaks, such as pipes under the sink or bath.

Penetrating damp often shows up through damp patches on walls or ceilings, which may darken when it rains. You’re more likely to get penetrating damp if you live in an older building with solid walls, as cavity walls provide some protection.

Speak to our experts for resolving your penetrating damp problems.