My mum's house has a damp issue in the front/flank corner of the hallway. It's a 1930s semi, and the driveway outside is higher than the ground level inside the house. Also, the external render reaches all the way down to the driveway. On top of that, the cavity in the flank wall next to the driveway has been filled with insulation 10-15 years ago. A free damp survey was done yesterday and he blamed the CWI and said that it was a simple job to tank the wall and replaster internally, but that doesn't sound like it will fix the issue of the render touching the ground and the driveway being above the DPC. Any suggestions? External images: http://imgur.com/GMTpLuG http://imgur.com/IqN9fFG http://imgur.com/6POHV6Z Interior (worse now, these are from a little while ago) http://imgur.com/nEcPg3k http://imgur.com/WvxPavm http://imgur.com/HP83q1n
Driveway is your problem. Ideally tarmac needs to be cut back at least 150mm, better if in line with drain gully surround, ground dug out, wall allowed to dry out. There should be around 150mm distance between dpc & ground level. Haunching around that pipe dosen't help, as it's bridging dpc as well.
KIAB has it nailed Lung. Needs some tarmac taking out and the wall needs to be able to breathe again. It's covered in cement tyrolean finish and then its base has a nice thick overcoat of tarmac. I supect the tarmac was dumped straight down on a pre-existing driveway. In fact the original driveway need taking up and the tarmac putting down on a good base of chalk or type 1. The levels are now out from where the original builder intended. That's my suspicion. The evidence of damp inside is due to the wall not being able to breathe. The plaster really needs removing and the wall can then dry out from both the outside and the inside. From what I can see it's not a real big job BUT it needs doing. The wall must be allowed to dry out as well and that will take time.
Wall will take months to dry out. Strip off that wallpaper, you might get away with not removing plaster. You'll probably find there is no tyrolean finish once you get below tarmac, just bare blockwork.
Lung, is that damp only on the section of wall to the left of the door and below the window? If so, that's a bit weird as the outside ground level at that point appears to be a lot lower than the tarmac drive. Is there any damp on the inside wall where the tarmac drive is? Anyways, as said above, that tarmac is too high against the wall. It might not be the toughest job - I can't see why a slot cannot be cut parallel to the wall, and - ooh - 150mm wide? Then excavate to below DPC level, allow it to drain into these currently cemented-over drains, and back filled with coarse gravel. Or a draining grid could be placed over the trough. Or even a grid placed half-way down, and then overfilled with gravel. Not sure about the lower crazy-paved part, tho'. Is the outside level there also above inside level? Once the source of damp has been sorted, the wall inside will sort itself over a few months. Hopefully the plaster is unaffected and can be kept. The 'paper will need taking off, of course, and a good mould-killer used.
I would also remove the big pot plat from beside the door to let the air circulate Take a notch out of the wall in this picture (http://imgur.com/6POHV6Z) where it joins the house. Not only is bridging the DPC but also acting as a barrier to hold the water against the porch. I bet there are no weep holes in the wall as well ? Certainly the guys is ramping up the costs by suggesting tanking the inside
Yep that what I meant, you could just see the guy rubbing is hands in expectation of sending in a big bill
Thanks for all of the replies. I'll try to add some details that I know, although the damp surveyors report hasn't arrived yet: The road to the front of the house was once a single track, but the council bought up lots of the front gardens and widened the road to a double lane with pavements and everything else. This happened long before we bought the house, so my guess is that the driveway was significantly steepened due to being much shorter. I remember from my childhood that it was concrete, so at some point it was tarmaced, but I have no idea what they did to the subsurface and whether the tarmac was just laid on the old drive. Devil's Advocate: No, that is an older picture from when this first became apparent (a couple of months ago), the flank wall is also damp in that corner, and gradually dries out over a metre or so away from the corner. The "crazy paved" section is at the same level as the interior floor. There is an airbrick in the front wall sat on this level.
I've had the report from the damp survey: "From our observations and random damp meter tests to area defined, damp sources present at the time of the survey were:- Rising damp - due to the lack of an effective damp proof course/bridging of original damp proof course by driveway, dampness was found to be rising in the walls hatched red on the attached sketch plan. Ground water penetration - dampness was also penetrating on a horizontal plane where ground/abutting floor levels are at a higher level as marked xxx on the attached sketch plan. Our damp proof course will be installed above these higher levels. All internal wall surfaces below the damp proof course level will require the application of a vertical waterproof membrane prior to replastering (see separate vertical waterproof membrane/replastering estimate). Perished plaster - due to the effects of dampness, the internal wall plaster has become salt contaminated/perished. Therefore, a minimum height of 1.2m of internal wall plaster, but at least 600mm into sound plaster, should be hacked off all walls that are being injected, and renewed to our specification (see separate quotation). Penetrating dampness - All sources of penetrating dampness e.g. defective chimneys, flashings, roof coverings, rainwater goods, rendering/pointing, window cills and door openings etc. should be remedied during external repair and maintenance works by the client’s builder. We would like to point out that concealed timbers in contact with damp walls are also at risk to fungal decay. The property may be prone to condensation during winter months due to high water vapour generation from cooking, washing etc. Extractor fans in kitchens and bathrooms are useful by removing water vapour at source. If a persistent condensation problem exists, the use of a dehumidifier would be very effective in controlling condensation. Deflection noted to hall floor to base of stairs, possibly indicating decay caused by dampness noted to walls. RECOMMENDATION We recommend that a chemical damp proof course be injected, and this report should be read in conjunction with our STANDARD SPECIFICATION ATTACHED. Our quotation for the injection of the damp proof course into the walls, hatched in red on the attached plan, amounts to :- QUOTATION: £310.00 + VAT" Plus the tanking membrane, which is another £900 + VAT. Ouch.
My report in one word BS regarding damp. Can't comment on whether you have defective chimneys, flashings, roof coverings, rainwater goods, rendering/pointing, window cills and door openings etc, no photo's. Why in the hell does it need tanking? You cut back that driveway to make a channel, & cut that concrete edging kerb back by handrail & removing plaster would speed things up inside, wallpaper will do for starters, then leave place to dry out for a few months, then see what the problem is like.
I'm going to contact an independent damp surveyor for a second opinion today. Mum wants to go with the first lot as she believes anything a professional tells her, sadly.
Show her this thread. Tell your mum to keep her money in the bank. The main cause of dampness in THAT driveway, it's at least 200mm too high, but angle of photo is deceptive.
As with anything, treat the cause not the symptoms. There are quite a few simple things to try on the thread above first. The other thing is we are giving our years of advice for free, we aren't going to get anything out of our recommendations. as Kiab says go through the thread with her
I suspect, Lung, that these 'damp specialists' (which they may well be) have a major draw-back - they only specialise in damp and how to treat the symptoms. They will happily do stuff like hack off plaster, inject all manner of chemical DPCs, tank, skim, etc etc. But what they seem reluctant to do is any other 'building' work beyond this. Any suggestion to them that they should perhaps cut a drainage channel against the house wall to stop this damp in its tracks will leave them staggering around in circles going "ERROR ERROR - we do not have the technology - this does not compute..." As Sospan says above, "treat the cause and not the symptoms". And the cause seems pretty much conclusively to be that the outside level has been raised too high. The solution - cut a narrow trench and excavate a draining channel adjacent to the house wall. You have drains leading into sewers there, so employ them too to take away any water that ends up in your channel. These specialists might well be able to block the damp coming into the house - we don't know - but isn't it best to stop that damp trying to come in in the first place?! They might be able to cure the issue as far as making the inside nice and clean again, but would you be happy knowing that that wall remains a soaking wet sponge with a thin skin on the inside to keep it all out? I wouldn't. Perhaps worth also calling out just a small - but experienced - general builder and seeing what they have to say?
Thanks again all, I'll get a "proper" damp surveyor out, and then assess. A decent builder seems the way to go.
The independent damp surveyor just left. As expected, he said tanking/DPC would not stop the problem, just move it elsewhere in the house. He also didn't think the driveway was too big an issue, as the flank wall is not damp away from the corner, and the drive has been cambered slightly to deflect water away from the wall. He reckons it's the front corner by the flowerpot, the crazy paving is pretty much impermeable along the front so water pools in that corner, and there's a small hole in the paving there, so all water that ends up at the front of the house is draining via that hole and into the ground directly in front of the damp corner. He says some work to change the camber of the paved area, plus a proper drain to divert the water away and into the main drain should fix it.
Well that's not too bad, certianly ain't going to cost the £1200+ vat you were quoted earlier to fix the issues. Could install a doorway drainage channel across width of path at front door & pipe water run off away from house.
Hi Lung. Will this second company do the work? Or are they just making a recommendation? It certainly sounds more promising, and by far what you'd want to hear! Sort the cause. Of course we can't tell from here whether it'll work, but it does sound more likely.
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