Garage - damp coming under damp course: how to patch?

[motso]

Hi all,

I've had a quick check through the archive and haven't come across any advice on this specific problem. The external wall in my integral garage built in the 60's backs onto the neighbours alleyway to their garden. Rain collects and is seeping through into my garage under the damp course, along with mud/soil. Hoping to make the garage a bit more hospitable for exercising.

I'm thinking some Blackjack or similar will help seal the wall, but what could I do first to fill/seal the gap under the damp course?

Thanks in advance,

Tom.

 

[JohnD]

Show us the outside, specifically ground level relative to height of DPC, and the gutters, downpipes and drains responsible for carrying water away.

 

[motso]

Hi John,

Thanks for the reply, its tricky as don't want to worry my elderly neighbour, but here is an over the fence pic. There is guttering above (it's a flat roof) but don't think it is leaking unduly. Seems to be the neighbours path has been cambered to collect against my wall... not sure exactly on the relative height I think this path is higher than my garage floor though.

Tom.

 

[JohnD]

The path is too high. If it slopes towards your garage you will not solve the problem until the path is dug up and relaid at the correct height. Can you see if the DPC in the neighbours house is also compromised?

From what you say I doubt you will be able to cure it.

On your side, you could trench out the floor against the wall, point up any gaps, and lay DPM turned up against the wall before refilling with concrete, and possibly a dwarf wall on the dry side, but unless the floor itself has a DPM, which can turn into a tray with raised edges, the floor will always be damp, and so will the wall. If you have a slope you could form the trench as a gutter to lead water outside.

You could lay DPM and put a new floor on top of it, such as decking boards, spaced enough to ventilate the void beneath, or you could pour a new concrete floor on a DPM tray. I do not think you can make the walls dry. You could fit a drained lathing as used in cellars to isolate an internal cladding.

 

[JohnD]

P.s.

The white marks beside the neighbours house might be soap residue from a leaking washing machine or bath drain.

Do not waste time and money on silicone injections

 

[^woody^]

Coat the exterior with a quality water repellant.

 

[Charlie George]

The path level looks fine for next door as it is, unlikely to lower their path to please you, single skin garages are prone to damp entering below the dpc

 

[JohnD]

there does seem to be a lot of moss on the path, as if it has been washed off a wet roof in heavy rain.

has it come off your garage, or the neighbour's house?