Is concrete outside bridging damp course?

[wadsterboy]

I moved into a 1900s semi last year. In the survey for damp, the firm carrying it out found damp in the front wall of the living room, below the window. However, as the mortgage company didn't put a retention on the mortgage, I wasn't required to do anything.

Now it's come to redecorating and I want to try and sort out the problem. So I have hacked off the plaster from under the window, which was slightly cracked and came off pretty easily, which suggests it was shot. However, the wall wasn't damp to the touch. I have read lots about the great DPC con, so I think I'm going to try and find the source of the damp. And I think this might be it...

You can see a picture here www.jawaddington.co.uk/outsidewall.jpg

As you can see, there's a sloped plastic cover on the front wall, which is designed to cover the cellar window. However, it goes quite high up the wall. Also, the concrete slopes up from the garden to the wall.

I'm struggling to see though, where the original DC might be - can anyone advise on whether it looks like the DC is being bridged by this outside stuff, or whether the concrete is too high and causing rain to splash up the wall? I'm planning on removing the concrete and therefore lowering the outside level, as well as moving the sloping cover further down the wall.

There is also a small garden wall that runs around the small front garden and meets the house. Funnily enough, the corner inside that is the dampest area in the whole room (the plaster feels damp - and it's round a socket!) is in contact with that garden wall. I'm thinking that I will chisel out the end bricks and mortar on the outside garden wall and insert a physical strip of DC vertically and then mortar back in - does that seem like a reasonable approach? Should the DC sit right against the brick or should it be sandwiched in between the mortar?

Any help appreciated!

Thanks...

Alex

 

[Softus]

I'm struggling to see though, where the original DC might be - can anyone advise on whether it looks like the DC is being bridged by this outside stuff, or whether the concrete is too high and causing rain to splash up the wall?

I can't see any sign of a DPC in your photo, but that doesn't mean it isn't there.

Everything in the picture is so far below the level of your internal flooring that I wouldn't expect any aspect it to be causing the problem.

I'm planning on removing the concrete and therefore lowering the outside level, as well as moving the sloping cover further down the wall.

It certainly can't hurt to do that.

There is also a small garden wall that runs around the small front garden and meets the house.

OOPS!

The wall meeting the house doesn't sound like a good idea to me, because it's prone to trap moisture against the house wall at a height above the DPC.

Funnily enough, the corner inside that is the dampest area in the whole room (the plaster feels damp - and it's round a socket!) is in contact with that garden wall. I'm thinking that I will chisel out the end bricks and mortar on the outside garden wall and insert a physical strip of DC vertically and then mortar back in - does that seem like a reasonable approach?

Possibly, but unless you can prevent water running down the wall behind the vertical DPM then I'd expect continuing problems. Lead flashing would work; sufficient mortar benching might work, as would a sloping tile affixed to the top of the garden wall to deflect the rain.

 

[kingandy2nd]

We had a similar comment on our survey that stated the outside level should be at least 150mm below the inside floor level. You're picture looks like you've got more than 150mm.

However, I wouldn't hurt to remove the concrete if it was part of you plans anyway. More important I would think is to re-grade the garden/yard so that the water flows away from the house - or at least ensure if water flows to a drain.