The Causes of Rising Damp, Risks & How To Deal With It

Rising damp is the common term for the slow upward movement of water in the lower sections of walls and other ground-supported structures.

There are many signs that would indicate you have rising damp problems within your property.

These include tide marks on your interior or exterior walls, salts coming through your plasterwork or brickwork, wallpaper coming away from your interior walls and even a change in the overall air quality (usually noticed by people not living in the property).

Rising damp occurs when your damp proof course (DPC) breaks down and allows water/water vapour from the ground to rise into the brickwork and then into the internal plaster thus contaminating it.

The water/water vapour that causes the problem contains hygroscopic salts (nitrates and chlorides).

They absorb moisture from the atmosphere which in turn increases the amount of water in the wall and the speed in which the damp will rise up the wall.

Although rising damp of up to 5 meters in height has been observed, the height of the damp rise is typically much lower and is rarely above 1.5m.

Rising damp has been a widely observed phenomenon for at least two hundred years. There is also strong evidence to suggest that it was a problem understood by the Romans and Ancient Greeks.

Rising damp has been proven to have a negative effect on the human body especially those listed below
Babies and young children
The elderly
Those who suffer from skin conditions such as eczema
Those who suffer with breathing problems such as asthma
Those with a weak immune system

This is backed up by the NHS and can be found on their website on a page entitled can damp and mould affect my health?

Rising Damp Treatment

Firstly we remove the contaminated plaster to a minimum height of 1 meters from the internal floor or 300mm above the last trace of damp if plaster is contaminated above the 1m measurement.

We would then insert our chemical into holes drilled with correct spacings between.

We include vertical DPC injection where applicable. The chemical we insert into the wall will provide the protective barrier and thus stop the damp from rising above that point again.

The brickwork would then be treated with an anti-sulphate solution to stabilise the salts ensuring no further contamination to the new plaster.

Once left to dry a little, we apply a lightweight cement based renovation plaster and once the correct wall levels are made we then allow to dry.

Please note: the renovation plaster used needs 12 hours minimum to cure owing to variables such as the water quantity present in the wall.

We then refit the skirting boards and if new is required we will source and refit for extra cost. We even remove and remount the radiators.

The next step is to skim the treated area to a smooth finish.

Although not mandatory, Midland Damp Doctor strongly advises that the whole wall is skimmed to eliminate the line that is visible. When the skimming process is complete you can usually see the meeting point of the renovation plaster and the existing plaster.

By skimming the whole wall you eliminate any visible line once dry.

Please note: you cannot feel a difference in the plaster as it is blended in by our (NVQ level 2 qualified plasterers). (Link to the qualifications all our plasters will have)

The process and products we use ensures all our work is completed to British Standard for both internal plaster finishes BS – 5492 1990 and for a chemical damp proof course BS – 6576 – 1985.

Rising Damp Warning!

Some other damp proofing companies and cowboy builders have been known to substitute the lightweight renovation backing plaster for cheaper products such as regular sand and cement with added waterproofer or even normal carlite based plasters.

This goes against British Standards and is not recommended. This may also create other problems, because of the weight and mass of the material it may attract condensation.