Damp Proofing


PermaFix offers a mature, common-sense approach to damp proofing walls in old houses.  It is vital that the cause of dampness is correctly diagnosed in order to prescribe an appropriate treatment to remedy the problem. Effective damp proofing involves removing the moisture source or by providing a water repellent layer to prevent moisture from being transmitted into the home.

In order of being the most common, damp in houses can generally be attributed to one of the following;

  • Condensation occurs when air moisture content is too high in relation to temperature. It can be controlled by correcting the balance between moisture generation, internal temperatures and ventilation.
  • Penetrating damp occurs when moisture from an external source finds its way into the home.  With regular building maintenance such as repairing gutters, filling cracks in walls and repointing etc., this can avoided. Where porous walls are subjected to driving rain then breathable water repellent treatments make walls water tight whilst allowing moisture trapped within the wall to evaporate.
  • Rising damp occurs when a damp proof course is missing or is breached. It can be resolved by removing soils or cavity blockages that bridge the damp proof course. Where a DPC is missing or is defective then remedial damp injection treatment can be used to combat rising damp.

What is a DPC?

A DPC is the abbreviation for a Damp Proof Course. it is a waterproof layer that is built into a wall to prevent ground water from being absorbed into the home. A built-in DPC may consist of a horizontal layer of slate, engineering brick, bitumen or plastic. Some older buildings may have no damp course at all. Moisture from rising damp is uniquely identifiable through the presents of ground water salts, which are deposited when moisture evaporates

Different types of bricks and mortar have different levels of porosity. Modern buildings with cement mortars have lower absorption rates than older buildings with lime mortars. It therefore follows that damp proofing treatment is more often required in older properties.

Retrofit Damp Proofing

For effective damp proofing, a water resistant layer is introduced where the physical damp course is missing, irreversibly breached or otherwise ineffective.  A silicone based injection cream is inserted into the wall where it cures to form a chemical damp proof course. Salt contaminated plaster is removed and an air-gap membrane is used to allow the wall to dry out and to facilitate immediate plaster reinstatement.

PermaFix only use independently tested BBA Certified DPC chemicals. Our damp injection and membrane treatment makes damp proofing walls quick, cost effective and permanent.