Damp proof injection holes

[bbegent]

Hi all, looking for some advice.

Long story short:
-moved into house,
-realised there was a damp problem
-got told the classic rising damp story
- noticed all the airbircks had been rendered over and floor was rotten
- had floor rebuild and airbrocks added at subfloor level
- Also noticed windows had no been properly sealed and rectified this

This solved 90% of the issue

However now there are a few isolated bricks that are still very wet. Note the bricks above and below them are dry.
The bricks in question have all been drilled in the past for a damp proof injection (there are other bricks that have been drilled that aren't wet).

Also outside of house is rendered down past this level so can't see the bricks that were drilled from the outside.

Render is in good condition other than a small crack around the gas pipe entry, bricks that are on show could probably do with repointing?

Am I right in thinking these holes are letting in water causing penetrating damp? If so what is the best solution?

Patch the render, repoint the brickwork and fill the old holes somehow??

Picture attached for reference.

Thanks in advance

 

[noj]

Probably just need to give them more time? When they're dry just fill the holes with a bit of lime mortar/plaster.

And the usual case of an injected dpc above floor level, keeping the bricks around the joists as wet as possible!

 

[aockenden]

And the usual case of an injected dpc above floor level, keeping the bricks around the joists as wet as possible!

LOL! Ruthless… but accurate.

 

[aockenden]

Wait, I thought you said the injection holes had been rendered over externally? If that’s the case then how would they be allowing penetrating damp in from the outside?

 

[bbegent]

Wait, I thought you said the injection holes had been rendered over externally? If that’s the case then how would they be allowing penetrating damp in from the outside?

Good point but I'm wondering if it's from water trapped behind the render from when the windows were unsealed or from the crack around the gas pipe

 

[bbegent]

Probably just need to give them more time? When they're dry just fill the holes with a bit of lime mortar/plaster.

And the usual case of an injected dpc above floor level, keeping the bricks around the joists as wet as possible!

It's been quite a while now and they seem to get a bit better then worse again, not sure more time alone is the answer

 

[noj]

It clearly shows that the injected damp proofing hasn't damp proofed those bricks! Explains why they then cover their holes with 1m of waterproof plaster too.

The holes could be penetrating into a cavity that's filled with moist debris (if you've got a cavity)? Or simply go into a cold void making those bricks cooler and prone to condensation?

Poke a stick or ideally an endoscope in and see if there's any difference between the wet and dry bricks, or depth of holes.

 

[aockenden]

Good point but I'm wondering if it's from water trapped behind the render from when the windows were unsealed or from the crack around the gas pipe

Ok but you’ve also said you fixed the leaky windows at this point? Surely if that were the original source of damp penetration, these bricks would be gradually drying out more and more now that it’s fixed.

Hard to tell from the pics if this crack near the gas pipe looks like a plausible explanation for the issue or not.

One obvious question is, is this a cavity wall or not?

 

[bbegent]

Not a cavity wall