Weep holes and rising damp: What should I do?

  • Creation Date: Wednesday, 19 June 2019

This interesting question came in recently:

I live in an area where the water table is high. As a result, I have paint bubbling, at the bottom, on the inside of an exterior wall. I assume this is a result of rising damp. I have noticed that newly built homes have  weep holes, at intervals, along outside walls. My house does not have these holes and I was wondering if I should drill some holes along the outside wall to stop the rising damp and as a result stop the paint on the inside from bubbling. Is this advisable? Please advise.

Les responds to this reader as follows:

Thank you for your enquiry. This is a common problem and the vast majority of "quick fix" methods tend to be a medium-term solution only. The most common solution is to drill many holes into the wall on both inside and outside and impregnate the wall with a silicone based product that seeps into the brickwork and then solidifies to form a moisture barrier. The problem may reappear in time where the penetration of the chemical was inhibited or did not reach. Simply drilling holes in the outside of the wall will not solve the problem of rising damp as it works by capillary action and moisture will simply work around the holes that were drilled.