Q. I bought a house recently which has a 30 year damp course guarantee.  It still has about 27 years to run. However, when carrying out some building work, I have discovered that the damp coursed walls have in fact been dot and dabbed, and then plastered.  Will this cause a problem for me later on, and with the guarantee?

Submitted by: D
 

A. Dot and Dab is certainly not an advisable procedure to use on walls that are known to have suffered from rising damp.

Moisture is always likely to be present at low level. What might happen is that moisture is absorbed by the porous plaster dabs which then passes through the plasterboard to eventually show as damp 'circles' on the decorative finish. This could cause you problems on your guarantee but whose guarantee? If the contractor who put the DPC in also did the dot and dab then he would be liable. He might also be liable if he did not leave adequate instructions for others with regard to the importance of correct re-plastering and what the consequences would be if these instructions were not followed. If you are talking about a third party guarantee then you are in trouble as dot and dab is not a recommended procedure. See BS 6576 and BRE Digest 245.