Bridged dpc and tanking advice

[peter1450]

Hi Have a detached house that at some time in the past a neighbour has had a path laid above the dpc level and we are experiencing damp on our inner walls. the walls have an unfilled cavity and we don,t get on with said neighbours ,so apart from a costly legal battle and an unsellable property i,m looking for a way we can solve the problem from our side! I was wondering if anyone has any experiance with tanking as done in basement flats etc or am i looking in the wrong direction? Any advice gratefully received.Cheers Pete.

 

[Softus]

How far is this path from your wall, and why do you think the DPC has been "bridged"?

 

[markthebuilder]

always treat the cause not the symptom
if it is due to nabours path then you need to get it lowerd or otleast you need to be abel to excavate and tank externaly
try a new aproach with nabour (ask him if he knows anything about damp and if he implies he dose aske him to look at yours and tell you what it is and what you should do about it) at this stage don't let on that you think its his path.

 

[Softus]

What a marvellous, helpful, and pragmatic post by markthebuilder.

Deep respect.

 

[peter1450]

The concrete has been laid directly against our exterior wall and approx 12 " above our DPC coarse. I would have thought this would be classsed as " bridging", especially if the bottom of the cavity is filled with years of builders rubble etc, any suggestions Softus?

 

[breezer]

although you dont like the way markthebuilder put it, he is right, if the path is 12 inches up your wall (so above the dc) the only solution is to remove it, but you only have o get it away from your wall.

perhaps a pic would help us all understand.

pic info is in forum information

 

[Softus]

The concrete has been laid directly against our exterior wall and approx 12 " above our DPC coarse. I would have thought this would be classsed as " bridging"...

Really? I'd class that as criminal damage. Failing that it's straightforward negligence. Either way it's going to f*** up your house big time.

 

[masona]

The concrete has been laid directly against our exterior wall and approx 12 " above our DPC coarse.

The only way is to break the concrete path up.

 

[gangman]

Peter
The problem you have is that damp is able to pass from the exterior wall to the inner wall. For this to happen the cavity must be bridged and this normally down to careless bricklaying. I've just done a job where I cut a new door opening in an exterior wall. The cavity was full of crap up to about a foot above the dpc and I've seen lots of cavities like this. You'll probably find yours is the same.

A lot of the time even if the cavity is bridged you don't get any damp inside it depends on how wet the external wall gets. In your case, with the path so high up your wall the moisture in the ground is enough to travel through to your inside wall and if the fall of the path is towards your wall, that's not helping either.

So if altering the path is not an option you'll have to clean the cavity. The best way if possible, is to cut holes at either end of the wall so you can see down the length of the cavity. Using a length of timber with a nail or screw through the end, pull out as much of the crap as you can. Try to clean out to about six inches below the dpc. When you come across some tight bits you can normally knock them loose by hitting the timber with a lump hammer. If you can't get at it all this way then you need to cut a series of holes either along the outside wall, but if that's not possible then on the inside wall. This way means a lot more making good but it's what you have to do to get the job done.

Let us know how you get on.