Rising Damp


Rising Damp

What is Rising Damp?

Rising damp is the term used to describe when moisture is absorbed from the ground into a wall.

Rising damp is caused by the rising of groundwater through capillary action. This means that ground water is effectively sucked up through tiny tubes in the bricks, like a series of straws. This water contains salts that also travel up through the wall causing the wall plaster to become hydroscopic. Rising damp primarily occurs in properties built prior to the 1950s. Most modern-day houses now have a DPC installed at the initial construction phase.

Rising Damp – what to look out for

Internal Signs

Symptoms of rising damp on internal walls include:

  • Decaying skirting boards
  • Damp patches on walls
  • Efflorescence (salt forming) on walls resulting in contaminated plaster,
  • Mould developing
  • Peeling and/or blistering of wallpapers and paints.

External Signs

Symptoms of rising damp on external walls include:

  • Efflorescence (salt forming) on exterior walls
  • Discolouration on exterior Walls
  • Corrosion of bricks and mortar

Rising Damp – Treatment

Internal work

Our experienced technicians will remove the contaminated plaster, fit a vented damp proof membrane to internal wall, reframe, insulate and plasterboard wall. We work in conjunction with other trades so if you would like us to take care of plaster work, electrical work and decoration we can provide a competitive cost for those trades too.

External work

Technicians will drill a series of holes in the wall at regular centres and insert a Damp Proof Course cream. The cream is delivered by hand pressure only from a simple applicator gun holes drilled into the mortar course. From here the low molecular weight Silane effectively migrates into the masonry pores and fully passivates across the mortar joint as the cream reverts to a liquid phase. Upon curing a hydrophobic chemical damp proof barrier is formed in-situ. Curing of the DPC starts immediately with the final cure taking 2-6 weeks depending upon wall thickness.