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Harringay, Haringey - So Good they Spelt it Twice!

I'm fighting - so far unsuccessfully - to contain a rising damp problem. Despite investigating pipes and drains, remedial work to damp courses and walls, and removal of loads of rubble chucked under the floors by previous builders that stopped air circulating, the sodden earth persists (there are no proper foundations, of course, thanks to Victorian spec building).

Years ago I was told that the N15 side of Green Lanes, where I am, has a very high water table, so it could be that what I'm dealing with is ground water, rather than a leak or one specific source. Does anyone know if this is true? If so, is there any remedy that works (short of sinking an Artesian well in the back garden)?

Tags for Forum Posts: damp-proofing, stonebridge brook

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The culverted Stonebridge Brook runs under your neck of the woods. Not sure if that has any impact.

Thanks, Hugh. Good idea, but from maps it looks as though the brook is further east and south of me; I'm off St Ann's Road, so I suspect it's probably not the culprit. Mind you, as a soggy part of the world, with streams and rivulets draining into the Lea, I suppose it's marshy underfoot almost anywhere.

I can see from your profile which road you’re on. If you’re near St Ann’s Road, I think that’s pretty much where the river runs. I put a description of the route in one of my Wikipedia articles. Take a look at the Geography section here

Which map are you looking at?

We are N15 and I think pretty close to the stonebridge brook.

We started with dreadful damp in the walls 12 years ago. Over the course of time, causes have included:

  • clay soilpipe leaking underground
  • cracked render
  • gap in coping stone on the top story
  • no/blocked airbricks
  • raised ground level from paving
  • leaking pipes under neighbours' staircase

One by one each cause has been found and dealt with. We still have damp from a leaking extension roof but the ground level damp is pretty much gone.

I can't say this applies to you as well, but my gut feel is that because these Victorian houses have been abused so many ways over the years, it's likely your damp has lots of contributing factors and it may be a case that you don;t really fix it til they are all dealt with.

Have you checked to make sure ground levels outside the house haven't been raised above the original damp proof course?  That happened in my property - i've got a Victorian house in N15, with a course of slate running 1 brick below the airbricks.  But some idiot had laid crazy paving abutting the house, right up to the air bricks.   They'd then ridiculously injected a chemical dpc above the level of the ground floor floorboards.

SOLUTION: I had to replace a lot of floor timbers which had rotted, but i've now drug a simple 30cm deep French drain filled with shingle along the front of my house - making sure that the shingle level stops a few centimetres below the slate dpc.   

Hi I had a similar problem with a ground floor and basement in N4, was solved by removing rubble from floor voids, reinstating airbricks and adding one extra, digging down to foundation footing level then digging a trench below making a circuit around the edges and looping through the centre filled with pea shingle burying a perforated pipe with the end connected to the garden gully. This was then coverered with a waterproof concrete slab it’s kingspan insulation slabs, a waterproof membrane and rebar to the slab which was then screeded, some professional (not diy) dpc injections, 4 layers of tanking and waterproof rendering to all walls internally, followed by plaster and some areas plaster boarded and skimmed, replacing rotten damp timbers to upper floor and laying a water proof membrane below.

It wasn’t easy, and wasn’t cheap. But it did work! 

Hi - We're having a big problem with ground water at our house in Pemberton Road. Seems to be a mystery why it is coming through (we've had all the plumbing checked and have reinstalled the damp proof membrane in our walls). Would you be able to share how you sorted this out and perhaps any companies that helped? Thanks

Alice — To be honest, I haven’t really found a solution. My builders and a specialist damp surveyor took another look, checked the damp course, etc, but were really none the wiser, so there was no obvious course of action. The property next door has been undergoing endless renovation for years and, since I first wrote here, has recently had the mains water inlet and ground floor plumbing/sewage pipes replaced. Although the owners apparently didn’t find any leaks, I’ve wondered if there might have been a slow one all the same. I probably won’t learn any more until we reach winter (when everything’s obviously wetter anyway) and I can assess if there’s any improvement. Sorry, this doesn’t help much, though I wonder if the slope of Ladder roads such as yours also makes houses there more prone to problems from water running down from the crest on Wightman?

Thanks all for very helpful suggestions. Some things are definitely OK - air bricks are unrestricted both at front and rear, so underfloor circulation is good, and there's a French drain at the front (I also replaced rotten joists and floorboards and had the drains photographed for leaks) - but I'll look into the other ideas. The main problem is under the stairs and against a party wall (maybe not helped by next door being uninhabited since building work stopped a year ago, though the problem pre-dates that), which is why I wondered about ground water; no obvious external sources there, such as leaking downpipes, and main drainage is at the rear. Earth under the front hall is dry, so it's not rainwater seeping in under the front step. Very frustrating!

Hugh: I looked at a map from Haringey Rivers Forum, which placed Stonebridge Brook south and east of Seven Sisters Road, near the other end of St Ann's, but I've read your linked Wikipedia article since, so thanks for that (sorry, can't get the system to put a reply to your post immediately below it).

Thanks for the suggestion; I took a look before and all seemed well, but the meter's just outside the front gate, so I'll check again to see if anything's changed.

Where is the damp manifesting? I have an inexplicable patch of damp wall in our property - ruled out leaks, and I have (sort of) ruled out condensation due to concrete in the render as the exposed bricks continue to be c. 30-60% moisture content with the meter without any render on them...

There can't be any leaks because we don't have any pipes running in that area, and we inserted an additional layer of DPC below that part of the wall last year... very peculiar.

Thames Water have plans to de-culvert the river in Chestnuts Park to relieve chance of flooding in the area - maybe the culverted water is already having an effect.

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