F.A.O builders, dampness rising

tonyh66

you need to find the damp course and roughcast above it, roughcasting down into the channel will achieve nothing but more damp.

DaftyDuck

Yep, whatever you do, don't render down into the gulley.

Frankly, I'd leave that channel as it is for a couple of months, let it dry out the best it can, and see what difference it makes.

Repair in haste, repent at leisure, as the expression doesn't say...

glasgowdan

Out of interest, the "damp" company quoted 1400+vat to sort the inside, take back, membrane and plaster, no hard sell or even follow up call so they didn't seem too bad, but I definitely want to focus on the outside so won't be going for it.

tonyh66

glasgowdan wrote: »

Out of interest, the "damp" company quoted 1400+vat to sort the inside, take back, membrane and plaster, no hard sell or even follow up call so they didn't seem too bad, but I definitely want to focus on the outside so won't be going for it.

you might not need any of that if you fix the outside first, inside could dryout on its own.

Mutton_Geoff

Are there any doors built into that extension (round the corner we can't see?). If so, the DPC should follow a line immediately under the door sill around the building. Count how many bricks up from ground to bottom of door sill, follow that round the building and remove the render to one brick above the DPC.

Careful use of an angle grinder and bolster should leave a neat job. I bet that cures the problem though it probably won't dry out for a few months through the winter unless you buy or hire a decent dehumidifier.

Interested to know if the company that rendered that wall are still in business.

glasgowdan

So roughcast to a bead above the dpc and leave the brickwork below it exposed? Sorry if I'm just repeating what folk are saying, I just want to make sure I'm getting it right! I'm getting the roughcasters in to talk over the job and update the quote.

There are no doors to follow back as the front of the gouse is roughcast to the driveway level, no exposed bricks. Is chipping back the roughcast something I can do myself without worrying too much about damaging the bricks? I've a 3" bolster.

Mutton_Geoff

glasgowdan wrote: »

So roughcast to a bead above the dpc and leave the brickwork below it exposed? Sorry if I'm just repeating what folk are saying, I just want to make sure I'm getting it right! I'm getting the roughcasters in to talk over the job and update the quote.

There are no doors to follow back as the front of the gouse is roughcast to the driveway level, no exposed bricks. Is chipping back the roughcast something I can do myself without worrying too much about damaging the bricks? I've a 3" bolster.

You mention earlier a lot has blown low down. As that's coming off for repair anyway, that's where I'd explore for the dpc.

Doozergirl

glasgowdan wrote: »

So roughcast to a bead above the dpc and leave the brickwork below it exposed? Sorry if I'm just repeating what folk are saying, I just want to make sure I'm getting it right! I'm getting the roughcasters in to talk over the job and update the quote.

There are no doors to follow back as the front of the gouse is roughcast to the driveway level, no exposed bricks. Is chipping back the roughcast something I can do myself without worrying too much about damaging the bricks? I've a 3" bolster.

That's exactly what you do.

If it's blown, then it will come off really easily. The bricks will already be slightly damaged by the render, it's not ideal that they've been covered and then uncovered and left. They may spall over winters. And er, could be prone to damp.

You can only try. See how they look.

teneighty

If I could just chip in. You are trying to complete the puzzle with half the pieces missing.

1. You need to establish the wall construction...probably cavity
2. Position of Damp Proof Course?
3. Position of external ground level and internal floor level
4. Note the pattern of damp readings to try to locate source.

Once you have all the information draw a simple sketch section through the wall, that will help you understand how the damp is bypassing the DPC or where else it might be coming from.

Chances are if it is a 1970's build it will be a cavity wall with a damp proof course. It is possible that the DPC is bridged, debris in cavity is quite common, internal floor membrane not lapped to wall DPC so plaster bridges DPC etc. etc. etc.

Until you identify the actual cause then any remedial work is just guesswork.

vw100

Check if the roughcast render is cracked, mine was and ripped it all down and rendered it with sand and cement. Result no more damp and mould on the interior walls.