What is Damp and How Do I Fix IT?

Damp is a common problem in homes, and it can cause a lot of damage. It's important to know how to spot the signs of damp, which include mould or mildew around windows and doors, a musty smell and discoloured patches on wallpaper and walls. Here we look at how to identify the different types of damp, how to treat damp, the cost of damp proofing and what to do if a homebuying survey shows signs of damp.

What is 'Damp'?

Damp is moisture that has been absorbed into porous materials such as stone, brick or concrete from the surrounding atmosphere. With time these materials expand as they absorb moisture from the air and this causes cracks in walls or floors. The moisture then evaporates back into the air leaving behind salts that are deposited onto surfaces such as paintwork or wallpaper. In addition to this salt deposition there may also be fungal growth (usually black mould).

How Do I Spot Signs of Damp in My Home?

It is important to recognise damp in your home and deal with it quickly to stop damage to the fabric of your property being done. If left alone can cause major problems in your home, especially where the dampness has prolonged contact with structural timber elements of your property, in this instance the damp can lead to rot which makes the whole damp problem much more expensive to resolve. There are also the health issues related to living in a damp home to consider. 

Below are common signs of damp to look out for, if you spot any of them you should take action fast.

  • A musty smell

  • A sense of increased humidity in the air

  • Discoloured patches on paint or wallpaper

  • Water droplets forming on walls or windows

  • Patches of dark mould on walls, ceilings, or around windows

  • Damage to skirting boards which exhibit signs of rot

  • Signs of a white residue on walls from soluble salts

  • Walls that feel cold when touched

  • Peeling wallpaper

Three Main Types of Damp

Not all damp is the same and each of the main types needs to be treated differently to solve the issues they cause. The three main types of damp are rising damp, penetrating damp and condensation.

Rising Damp

Rising damp is the process of ground water being drawn up through brickwork by capillary action. Moisture visible at the base of a wall could be rising damp, especially if a ‘tide mark’ is visible. The tide mark is often visible up to 1m or more above the floor level, sometimes higher, and may be accompanied by salt marks in the plaster as ground water contains salts that are left behind as visible marks when the water evaporates.

Houses built after 1900 will usually have a damp course in the wall and modern houses will have a membrane under the floor that links to the damp proof course to seal against any water coming in. If the barriers become damaged or compromised

For many homes, these barriers can be damaged, worn away, or compromised by higher external ground levels over time. Without these barriers, damp may start to appear on the walls or floors of your home.

Penetrating Damp

Penetrating damp is normally caused by defects in the fabric of the building that allow water ingress, such as blocked gutters, weathered pointing, defective roof coverings, poor maintenance of rainwater system, gutters, drains and downpipes, broken masonry or poor seals around windows and doors. The cause of the water ingress may determine how localised the effects are and how expensive the issue is to fix.

Condensation (& Mould)

Condensation is often recognised when you see water droplets running down walls or windows and sometimes through the presence of black mould on walls or ceilings. The majority of condensation issues are caused by inadequate heating and a lack of ventilation. 

How to Fix The Causes of Damp

Once you have identified that you have damp it is important that you fix the causes as soon as possible. If you need help to identify the type of damp and the causes, an independent damp survey will be your best bet to get reliable advice without the worry that the person giving you the advice wants to sell you remedial work to fix the issue. The recommended treatment depends on the cause and there may be multiple causes contributing to your issues, making identifying the cause and remedy tricky.

Fixing condensation issues

The best way to reduce condensation in your home is to produce less water vapour and improve extraction. When you cooking use a lid on the pan and turn the hob down once the water has boiled to reduce steam; avoid drying washing on radiators ventilate the room you are using by opening windows; vent your tumble dryer to outside or use a condensing dryer.

Fixing Penetrating Damp

Some issues such as a low level blocked gutter might be a DIY job, but fixing most building defects will require a contractor.

Fixing Rising Damp 

Determining whether you have rising damp is generally a job for a specialist damp surveyor who will also advise on the cause and remedy.

If you are unsure about the cause or solution for any form of damp we recommend you speak to a specialist damp surveyor in the first instance.