Resolving a few suspected damp issues

[rhysjc]

Hi all,

We're getting pretty close to completing on a 1920s/30s solid wall semi, so I've decided to finally stop lurking and make an account here.

We had a survey done prior to exchange which noted high damp readings in a couple of places, as well as a few potential causes:
1. Pebbledash render all the way to the floor, bridging the DPC (if it exists - hopefully it does!)
2. External ground level too high
3. Downpipe discharging directly on to the ground

I've done some research on how I can resolve all of the above but I'm left with a few questions I'm hoping someone can help answer!

My plan for the pebbledash is to remove a small section to the side to find the DPC level, then use an angle grinder to score the render two or three courses above the DPC. I'll then use a chisel and hammer or potentially a chisel bit on an SDS drill to remove the render below this line. I can then install a bellcast bead and render above this to join to the existing finish and add new pebbledash to match. Does this generally sound like a good approach? I've read online about having to use lime render so the walls can 'breathe', is this necessary given the existing render is likely cement? I've also read about the danger of removing the 'face' of the brick - is there much I can do to avoid this? Finally, would I be safe to use some breathable masonry paint below the new render, given I imagine the brickwork isn't particularly pretty?

For the external ground level, I think all I can realistically do is cut a channel in the ground, maybe around 5" wide. I could then fill this with gravel, install a french drain or run an ACO drain to wherever an existing downpipe empties in to a drain. Which of these is the best approach? It's worth noting here that given the render is all the way to the floor, the surveyor can't conclusively know if the ground level is actually too close to the DPC. They do suspect this though!

The solution for the downpipe depends on what I do for the above. If I was to install an ACO drain I could have the downpipe discharge in to this, with the ACO then carrying the water to a drain.

Apologies in advance for the lengthy post full of questions, I've done a lot of research here but the more I read the more questions I have!

Thanks a lot

 

[^woody^]

Are the high damp readings related to those three things you mention or are they even related to penetrating or rising damp?

Otherwise, item three is the only one that definitely should be rectified, the other two are not issues unless they are causing problems.

There's a lot of repetitive nonsense on houses needing to breathe and using lime mortar or even lime render. If you have cement render, use that, it's not a problem.

A rainwater downpipe needs to go into a rainwater drain or soakaway or across paving to then direct it somewhere suitable. Its rare for a downpipe to be just discharging onto ground. If the drainage is combined, then the connection needs to be trapped. It should not go in to a foul water drain.

 

[rhysjc]

Thanks for the reply Woody!

It was only a level 2 survey rather than a damp survey, so they didn't go in to that much detail. It had been seriously wet when the survey was done (this was around March, didn't stop raining) so certainly could have been penetrating damp. The damp readings were at the front in the living room near where the downpipe discharges, and to the rear in the kitchen. I imagine the downpipe is causing the issue at the front but unclear what the problem is at the back. There's a small patio there so I wonder if it doesn't have the right fall and water is pooling by the wall...the bridging render could then be carrying it up.

There's existing downpipes on the building that are being drained correctly so I imagine it'll be able to tap in to that in some way, though it might require relocating the downpipe to the other side of the porch.