Damp

SG27

Looks like the op has cross posted with their thread on the DIY forum. https://forums.moneysavingexpert.com/discussion/4612161

lottie0311

I just thought it fell into both and would be great for the most opinions.

I know the problem can't be soil outside the house, the house is surrounded by concrete and there is nothing built up against the house, the floor of the house is also concrete.

There is no problem with the internal decoration, which y gut feeling says surely it can't be that bad? I'm more bothered about what it's gonna cost as that will determine if the buyer wil still go ahead.

DRP

lottie0311 wrote: »

I just thought it fell into both and would be great for the most opinions.

I know the problem can't be soil outside the house, the house is surrounded by concrete and there is nothing built up against the house, the floor of the house is also concrete.

There is no problem with the internal decoration, which y gut feeling says surely it can't be that bad? I'm more bothered about what it's gonna cost as that will determine if the buyer wil still go ahead.

is the concrete outside above the DPC (or very close) ?

lottie0311

im not sure, all i know is that there are 2 bricks on the floor outside (the ones now covered in bitumen) and the only thing next to it is concrete, no soil etc anywhere.

would you think this would be a big job? especially considering its only been noticed by the meter and not by inspection of the internal decoration

G_M

Makes no difference if it is concrete or soil - if it is at or above the level of the dpc then damp can penetrate.

Sometimes for example people build a drive next to the house, using concrete. This raises the ground level outside, against the external wall, such that the concrete is above the dpc level. This can cause damp just as much as piling soil ora rockery against the wall.

The thing to check is where the dpc is installed. it should be about 2 brick layers above the external ground level.

lottie0311

ok that makes sense.

If the concrete is above the dpc, do we have to remove the concrete or can we inject another course higher up?

Also ,it is necessary to replace to plaster inside or will this dry naturally once the dpc is in? As i said, it doesnt appear damaged

G_M

I'm not an expert, but would suggest that removing the concrete and digging down a trench (about a foot wide? though there's probobly some regulation) alomg the side of the wall would be easiest. It narrows your drive (if that's what it is) by a foot) but means the ground level besie the wall is lowered.

Again, not an expert, but I imagine if the plaster is undamaged, it will dry out. Might be stained and need re-painting/re-papering.

lottie0311

cool i understand that enough. rather than digging though, would it not be possible another DPC injected?

G_M

lottie0311 wrote: »

cool i understand that enough. rather than digging though, would it not be possible another DPC injected?

Again, I'm guessing...

That would solve the problem of the concrete outside breaching the dpc. But internally, your dpc would now be x inches/feet higher. This might be an issue if it was, say, above the height of the floorboards, or the joists on which they rest, which could now get damp.

but I stress: I'm no expert, just picked stuff up by owning a 150 year old house for 15 years....

I've had lots of excellent help over the years from the DIYNOT forum. Try asking there.

SG27

If your house is that old it may have no DPC at all and injecting a new one probably wouldn't help, although it may satisfy your buyers. Our house has no DPC and external ground level is higher than internal. We have an a narrow drain that skirts round the side and back of the house to keep the water away from the external walls. We have some slight damp. Most likely condensation which we have a dehumidifier to help control.