Understanding Dampness in walls.

One of the common mistakes that property owners make with regards to damp wall issues is trying to carry out a quick fix to solve the problem by making attempts to paint the affected wall sections. It sounds ideal and very attractive, but hey, this never solves the root cause of the dampness and is rather most likely to re-occur if not fully dealt with.

Critical investigation by an expert is necessary to determine the type of damp and determine the most effective solution against it. If one  does not critically investigate the specific causes of the damp, he/she is most likely to offer a solution which is not required.



Bridging damp

It is caused when the external ground water table is higher than the   built-in damp-proof course. Similarly, it can occur when the internal  floor level of a structure is built above the damp proof course where the original floor has no damp membrane below it.

In cavity walls, bridging damp occurs if mortar or debris accumulate in the cavity and absorb water thereby exposing the walls to dampness. It can also occur can under the following conditions:

  • Application of external render over the DPC leading to direct contact of the wall with soil.
  • Also, soil or backfill raised higher than the DPC causes a bridging damp.





Penetrating damp

This is essentially excess water finding its way through an external point i.e walls, window/door opens, roof into a building usually because of an external defect.

  • Porous walls. Breathable walls are good but in whenever it rains or exposed to water, the wall is filled with damp due absorption of the water in contact.
  • Defective masonry. These act as weak points through which water is easily absorbed such as small cracks in the outside wall. As the damp builds up, these become bigger making the damp problem worse especially in old buildings.
  • Defective roof tiles
  • Cracks around doors and windows


Signs of penetrating damp in walls

  • Rotting skirtings
  • Presence of moulds
  • Wearing off of external plaster
  • Brick damages due the continuous absorption of water
  • Damp stains and patches



Internal factors leading to dampness in walls

Humidity.  Moulds are a great sign of a humid and this could be caused by probably poor mechanical ventilation.  Fighting this requires enough ventilation within the building.

Heating.   The internal temperature of a house should be fairly 200C under normal conditions. It is most expected in kitchens and bathrooms due to heat constantly emitted when in use. Too much heat say water heating emits vapor which condenses on the walls thus causing dampness. Here, insulation is the solution.


How do I treat wall dampness?

Before any treatment is proposed or rendered to fighting dampness in your walls, I suggest you arrange a detailed survey with our professionals at London Building Contractors, who’ll investigate, recommend and further treat against dampness in your walls to the dot.

If you are looking for expert technical solutions to solving any dampness problem in your home, office or any structure, London Building Contractors is here for you!



Posted on: December 7th, 2021 by London Building Contractors No Comments

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