DIY Doctor UK DIY Forums

Hi, I recently had a new damp proof injection in my circa 1980 house and where the guy drilled to inject and subsiquently filled the holes the bricks are damp in and around these immediate areas, the opposite of what i expected to happen, not sure if it just the damp proof sustance 'going off'. Does anyone know if this is normal or should i get him back around. We are not on good terms because of other work that he did in the house!

Any advise would be great.

stuartbest8,
If the injection was done with silicone liquid into the bricks they will look damp. I would not have expected this work to be necessary on a 1980s house so it may be the original DPC is forming a barrier to the silicone.
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Thanks for the advise, that sounds about right. We had a new injection done because we have had a damp problem on the ground floor which seems to be the whole way around and have had countless damp companies come in to look at the problem but with no definative answers. The internal plaster was put on right down to the concrete slab as well as the MDF skirting which we belived was acting as a moisture wick, the ground floor was re plastered up to a couple of feet and we thought that while this was being done we would do the injection too just in case it was that as well. I'm hoping now that this won't clash with the original DPC like you said and cause even more problems?!

Thanks again.

stuartbest8,
The concrete floor should have a DPM incorporated in it and this should have been lapped into the DPC around the walls. Therefore there should be no reason for damp to be rising out of the floor.
From the description of your problems I would suspect that mortar has been dropped into the base of your cavity walls and this is creating a bridge from the outer to inner leaf.
Sorry to tell you that I do not think this is the last of your damp problems.
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Hi.

This is what we feared, something in the cavity. Ill bet there isn't much that can be done about this either??! The walls at the moment don't have cavity insulation and i'm wondering whether this would help or hinder the situation?
Would you know any remedies for this?

Thanks again.

stuartbest8,
Cavity wall insulation will make the problem considerably worse.
Hire yourself an endoscope which includes a light source, drill holes through the outer brickwork courses big enough for the probe (2or3 courses above DPC level) and have a look to see if rubbish is bridging the cavity. If it is you will need to remove every 3rd brick one course above dpc level and dig out the fallen snots.
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