The incorrect installation of a DPC- You will be supprised to know that we even deal with new builds where the developer/ contractor has put the DPC in at the wrong height.
Bridged Damp Proof Course- This can occur for a number of reasons but one of the most common is piling up earth or other materials against the wall outside the house, for example in a flowerbed.
This allows water from the pile to seep into the wall above the DPC and rise up the wall. The remedy is to simply remove the soil/debris which will allow the wall to dry out naturally. Other ways in which a DPC can be bridged are within the cavity of the wall.
High Ground Levels- By far the most common type of bridging to a DPC that we at ATRUSS PRESERVATION find is through block paving and crazy paving. Over the years previous owners have laid new paths /paving over the old original ones - thus bringing the current ground level above the original Damp Proof Course.
How can I check to see if my Ground Levels are too high?
If your property has an airbrick near the ground level then check to see that the ground level is not higher than the bottom of the airbrick. If the ground level is higher then chances are that the dpc has been bridged, dependant on how long the dpc has been bridged will determine any remeedial works in the future. It may be necessay to remove the defective plaster and install a new dpc or it could be as simple as reducing the high ground levels in the form of a French Drain this it is higher
Sometime debris such as cement or mortar can fall to the bottom of the cavity and create a path over the DPC for moisture, the remedy here is to locate the debris and remove it. If the site is not immediately apparent due to a localised damp patch it may be worth taking advice from a professional.
If you are laying a path or patio next to the house ensure you allow sufficient height between the new surface and the DPC, ensure you check your local building regulations or take appropriate advice on this otherwise you run the risk of damp during heavy rain conditions.
Finally, external wall coatings can bridge the DPC so ensure that any cement renedering or coating such as pebbledash or a Tyrolean finish does not extend below DPC level.
Failed DPC - The Damp Proof Course may have failed due to incorrect installation, ageing or use of incorrect or sub-standard materials.
Where is the DPC in my house?
In most cases the original DPC is level with the bottom of the airbrick. See picture below right where the original dpc can now be seen with the reduction of high ground level.
LONDONS NUMBER 1 CONTRACTOR IN REDUCING HIGH GROUND LEVELS
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Should you require a no obligation quotation on damp at your property please contact us now on 07984 712 428 or alternatively please fill in our enquiry form where we will contact you back regarding a survey.
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