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A Guide to Rising Damp in Older Properties

Rising damp is a common problem in older UK properties built before damp proof courses started becoming standard. It occurs when moisture from the ground rises up through porous materials like brick or stone by capillary action. This leads to wet walls and potential damage.

Signs of Rising Damp

Rising damp is quite easy to spot in ground floor rooms, so it is something to look out for when viewing an older property as a buyer or potential tenant. If you are buying an older property, a home buyers survey carried out by a house surveyor in Norwich will look for issues like rising damp, and any problems will be highlighted in the survey.

The main signs to watch out for include:

  • A ‘tide mark’ on walls – a distinct horizontal damp band about 1 metre from the floor
  • Blistering, cracking or peeling wall plaster
  • Damp patches showing on walls, often getting progressively worse lower down
  • A musty smell and possible black mould growth on affected walls
  • Wallpaper loosening at the bottom
  • Rotting skirting boards at floor level

Causes of Rising Damp

One common cause of rising damp is the lack of a damp proof course (DPC) in properties built before 1875. A DPC is a horizontal barrier inserted into walls that blocks moisture rising up from the ground.  Modern homes have a DPC added at the construction stage. 

The failure of an existing DPC due to age and deterioration can also lead to rising damp. Chemical DPCs have a lifespan of 20-50 years. 

High groundwater levels or poor drainage drawing excessive moisture into the property from outside, which is often an issue in cellars below ground level.

Alterations like concrete floors or raised patios can ‘bridge’ an existing DPC and allow damp to bypass it.

Consequences of Rising Damp

Rising damp can lead to a number of problematic issues if left unchecked:

  • Deterioration of plaster, wallpaper and internal decor as moisture causes it to blister, bubble and peel
  • Damage to timber skirting boards, doors and floors as the moisture causes rot
  • An increase in mould growth which can aggravate allergies and respiratory issues
  • Damp encourages populations of insects like woodlice and silverfish
  • A general unpleasant musty smell throughout affected rooms
  • In very severe cases, weakened walls requiring extensive rebuilding

Treating Rising Damp

The main options for treating rising damp are as follows:

Installing a New Damp Proof Course

This involves cutting a channel into the mortar and inserting a new chemical or physical barrier to moisture. It is the most effective treatment if done properly.

An aging or damaged DPC can be replaced by a new one. The old DPC is raked out and a new material is injected into the space.

Moisture Control Systems

Electro-osmotic or chemical moisture control systems can be installed to draw moisture out of the wall. These are less intrusive than a traditional DPC but require ongoing maintenance.

Prevention is ideal, so when renovating older properties install a DPC where missing. Maintain a DPC by keeping exterior ground levels down. Consult a damp specialist if you have any concerns about rising damp. Acting quickly prevents further damage.

Jason Holder

My name is Jason Holder and I am the owner of Mini School. I am 26 years old. I live in USA. I am currently completing my studies at Texas University. On this website of mine, you will always find value-based content.

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