Damp on internal garage walls

Bendy_House

Danger_Mouse said:

Thanks for the advice. Can you paint directly onto the wall once tanked?

Pretty sure you can - it's effectively a cement-based slurry, so should easily take emulsion. Probably won't be pretty, tho'!

koalakoala

Can you not complain if it’s a new house?

Danger_Mouse

koalakoala said:

Can you not complain if it’s a new house?

Yeah we have done and we're chasing them. Hopefully the builders will sort it but I think they'll just say its single skin so some damp is likely to come through.

andyf1980

Danger_Mouse said:

andyf1980 said:

We used some Thomsons Water Seal on the exterior wall of ours and that did the trick. It is single skin brick. 

Did you put anything on the internal side of the wall mate?

No, we haven’t done. We were getting quite a bit of mould but this seems to have stopped it completely. 

Bendy_House

Danger_Mouse said:

koalakoala said:

Can you not complain if it’s a new house?

Yeah we have done and we're chasing them. Hopefully the builders will sort it but I think they'll just say its single skin so some damp is likely to come through.

Perhaps best to chase this to see what solution they come up with, because once you do something - even paint the inside - they might shrug their shoulders and walk away.

Another thing to consider is, once you paint the inside, then 'tanking' might be off the table for you; pretty sure it would need to adhere directly to the brick.

On that note, afaIk, if you want to be 'certain' of stopping penetration, then tanking is, I understand, the answer. So, for that 'certainty', that's what you should be doing. If you paint first, you might be stuffed...

Danger_Mouse

Bendy_House said:

Danger_Mouse said:

koalakoala said:

Can you not complain if it’s a new house?

Yeah we have done and we're chasing them. Hopefully the builders will sort it but I think they'll just say its single skin so some damp is likely to come through.

Perhaps best to chase this to see what solution they come up with, because once you do something - even paint the inside - they might shrug their shoulders and walk away.

Another thing to consider is, once you paint the inside, then 'tanking' might be off the table for you; pretty sure it would need to adhere directly to the brick.

On that note, afaIk, if you want to be 'certain' of stopping penetration, then tanking is, I understand, the answer. So, for that 'certainty', that's what you should be doing. If you paint first, you might be stuffed...

Thought I would update the thread. The home builders came round earlier and said they can't do anything because when we had the garden landscaped (nothing to do with the home builders), they paved right up to the garage and slightly above the damp course.

I never know whether to believe the home builders or not because they try to get out of things but what they are saying makes sense. They've recommended to cut a strip off the tiles away and gravel it and they reckon that should stop the damp

koalakoala

I would say they are correct

Bendy_House

Presumably the damp area correlates with the subterranean part?

Danger_Mouse

Bendy_House said:

Presumably the damp area correlates with the subterranean part?

Yeah exactly, its only damp on the bottom couple of bricks at the back and the tiling is on the other side of the wall so makes sense what the builders are saying 

Bendy_House

That's great news, then - cause found :-)

Yes, if you excavate away a channel, that should do the job. Use an angle-grinder to cut a neat line, I'd guess ~150mm away from the wall. Clear it away to comfortably below DPC, and then back-fill with coarse gravel, ideally still keeping to below DPC level.

Really, the ground outside should be at least 150mm below the DPC level, but that would mean a what?, ~200mm+ trench, which might threaten to collapse?

I'd excavate first, clean the exposed wall, and see how well it dries. The trench will need to be able to drain freely, so it cannot just fill up with water after it's been gravelled. You could always add tanking to that side before adding gravel, and this would be more effective than it would have been on the inside. Or Black Jack it. Or Waterseal.

What do folk think would be the best approach? I'm wondering if there's a way of back-filling it with gravel to prevent the sides collapsing, whilst making sure there'll be no further dampages.