Damp Proofing

Since July 1998, revised building regulations see all new dwellings and buildings required to incorporate some degree of radon preventative measures at the time of construction. The degree of protection required is dependent upon whether the site is located within a high or low radon area.

Radon gas prevention membranes also act as a damp proof membrane, preventing ground vapour from entering a building.

In a modern building, a watertight damp proof course is placed in block work at a low level, which serves as a barrier against upwardly moving ground dampness. In earlier times, rising ground dampness and its effects were not well known, and with the exception of very far sighted practice, old stone and brick walls were not provided with a damp-proof course.
 
The end result is that the affected walls are permanently damp at a low-level, being visibly affected in the form of damp staining of decorations, breakdown of plaster, deterioration of skirting timbers, window panelling timbers and doorframes.
 
We provide the two main systems by which rising damp is eliminated:

• Siliconate Or Liquid Chemicure Injection Damp Proof Course 
• Electro-Osmotic Damp-Proof System.

 
However, prior to committing to remedial damp proof treatments, with associated disruption and expenditure, it is essential that the actual cause of low-level dampness is established. Other factors could contribute; such as pipe leaks, incorrect level of damp proof course, defective floor, or high external ground levels.
 
If a building does indeed have rising damp, you would expect to see some or all of these issues:

A common area affected by falling damp is chimneys stacks. Where pointing, render and flashings have been fitted incorrectly or indeed just worn down over time, we can see damp staining on the chimney breast internally.
 
Falling damp in an attic space can also lead to issues with condensation. Attic spaces are typically humid areas; the perfect environment for mould spores to germinate and spread.

Buildings on sloped ground are more vulnerable, as the slow flow of groundwater downhill puts additional hydroscopic pressure on walls.
 
Lateral damp causes more problems than just an unpleasant odours, it can also lead to structural issues for walls which the entire building is relying on for support.
 
Lateral damp can be exasperated if hygroscopic salts contaminate the walls. These salts are constantly absorbing moisture from the air, which can rapidly accelerate a damp problem.
The increase in moisture content in the air can also lead to increased condensation and mould with all the associated health problems they cause.

The issue usually begins with condensation, which is amplified by cold bridging and both then lead to the presence of mould.
 
So, let’s start with Condensation.
Condensation is caused when moisture-laden air comes into contact with a cold surface –the air is cooled to a point where it can no longer hold its burden of water vapour. At this point, dewpoint, water begins to drop out of the air, and it is seen as condensation on surfaces.
 
Cold Bridging, also known as thermal bridging, is quite simply a gap in insulation. Such bridges are commonly found at junctions of a building i.e. wall to floor, window to wall.
 
Cold bridging is very common in older buildings where an emphasis on energy efficiency and air tightness wasn’t common place.
We can see that if cold bridging is likely to occur around a window and condensation is likely to fall on the glass, these two features are likely to lead to mould spores germinating and multiplying.
 
The positive outlook with these issues is there are many things that can be carried out by the building owner / occupier to alleviate the issues in the short term.