Tanking attempt on damp wall

[Ianharrison2000]

Hi,

I've recently paid quite a bit of money to have some walls stripped back to stone and tanked to prevent an issue with damp (I've also dug a French drain in the front to prevent water ingress). After only about 4 weeks I have damp once again coming through in the same places, but I'm not sure if the tanking has been done correctly. The tanking doesn't go fully to the floor, so it strikes me damp could rise on the inside of the tanking - but the builder assured me this was the correct way to do this.

Can anyone advise if this looks right, I'm not sure if I need to have the whole lot done again!

Ian

Sorry I think I've put this in the wrong forum and I'm not sure how to move it?

 

[freddiemercurystwin]

Tanking slurry's on the walls alone only work if the floor doesn't allow any damp through, otherwise you end up with this. How does the builder magically know the floor doesn't need tanking? Though there does seem to be a bit of dpm hanging out on the second pic. The slurry should have been applied to the floor too, did you both not discuss that beforehand? Slurry systems require meticulous attention to detail (ie mixing and application) and often a render coat on the walls if brickwork for example or a screed on the floor if that's in poor condition before the slurry and even then the water pressure behind the wall can push the slurry off.

IMO slurry's are very hit and miss and whilst the cheapest solution they're the least reliable and can then turn into the most expensive solution should you need to then redo it or redo it with a better more reliable system.

 

[Ianharrison2000]

Tanking slurry's on the walls alone only work if the floor doesn't allow any damp through, otherwise you end up with this. How does the builder magically know the floor doesn't need tanking? Though there does seem to be a bit of dpm hanging out on the second pic. The slurry should have been applied to the floor too, did you both not discuss that beforehand? Slurry systems require meticulous attention to detail (ie mixing and application) and often a render coat on the walls if brickwork for example or a screed on the floor if that's in poor condition before the slurry and even then the water pressure behind the wall can push the slurry off.

IMO slurry's are very hit and miss and whilst the cheapest solution they're the least reliable and can then turn into the most expensive solution should you need to then redo it or redo it with a better system more reliable system.

Thanks for the reply, I didn't discuss with the builder exactly how they were going to do it, I asked them to tank the walls and explained what the issues were. I understand the floor may have had DPM, but I was surprised it hasn't been taken down to the floor.

In order to resolve this is it possible to add tanking to the bottom bit or will it all now need re-doing?

Ian

 

[freddiemercurystwin]

Any break in waterproofing layer will be a weak spot, so linking the wall slurry to the floor dpm is vital. I suspect that's unlikely to be possible but really depends where the dpm is and how it's terminated in relation to the base of the wall and if it can be linked to the wall tanking. It might be that a floor slurry is required that can be linked to the wall slurry. You really need to find a suitably qualified builder to answer all that, perhaps some investigatory works to see exactly what's waterproofing the floor are in order.

Extending the slurry right down to the floor may work but I would be skeptical, you'll still have a break in the waterproofing layer.

Unfortunately if there is a way water tends to find it.