1940s bungalow with brick cavity walls that appear filled. Removed skirting and found lots of drilled holes just above timber floorboards - presumably created by chemical dpc application in the past. What should I fill these holes with before refitting skirting, that will not create an issue?
Internal chemical dpc holes - what to do?
- Thread starter BPO
- Start date
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Thanks. Size about 20mm diameter. I had been thinking woodwool or lime mortar to prevent any moisture issues? Try to stay away from foam - I just can’t control it 
and been advised not to use unless no other option due to its non breathability.
and been advised not to use unless no other option due to its non breathability.Sponsored Links
OP,
You can fill the holes with any kind of mortar or even custom rubber plugs - no problem.
But why, unless they have been drilled clean thro the bricks into the cavity, even fill them?
They will be covered by the skirting - they are not a problem as such. Forget about them.
More interesting, is why the wall had a DPC installed in the first place?
Why did you remove the skirting?
Any present signs of damp on either side of the wall?
You can fill the holes with any kind of mortar or even custom rubber plugs - no problem.
But why, unless they have been drilled clean thro the bricks into the cavity, even fill them?
They will be covered by the skirting - they are not a problem as such. Forget about them.
More interesting, is why the wall had a DPC installed in the first place?
Why did you remove the skirting?
Any present signs of damp on either side of the wall?
I'd use Acrylic sealant. It's not as flexible as silicone but will seal it then fully set and won't cause issues with anything else, e.g. glue for the skirting or paint. Silicone shrugs off most paints, so can be a right pain if you get the merest smear anywhere you ever want to paint.
The only issue with acrylic sealant is that it shrinks. So you'll end up with a recessed hollow where the hole was, which won't matter but it will be sealed.
I wouldn't leave them open. It's entirely possible that some will be into the cavity where bricks have broken out so they may have cold air blowing through. At best they compromise the insulation provided by the inner brick.
Silicone sealant can be weird. I used some on the edge of a floor then put commercial carpet tiles down. Despite being fully set, it liquified the backing of the carpet tiles which wicked up into the carpet pile as a black stripe along its edge. It's acidic and quite reactive, with sometimes strange results.
The only issue with acrylic sealant is that it shrinks. So you'll end up with a recessed hollow where the hole was, which won't matter but it will be sealed.
I wouldn't leave them open. It's entirely possible that some will be into the cavity where bricks have broken out so they may have cold air blowing through. At best they compromise the insulation provided by the inner brick.
Silicone sealant can be weird. I used some on the edge of a floor then put commercial carpet tiles down. Despite being fully set, it liquified the backing of the carpet tiles which wicked up into the carpet pile as a black stripe along its edge. It's acidic and quite reactive, with sometimes strange results.
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