Would be grateful for some help on this problem I have with my house which is of poured concrete wall construction circa 1930, wall thickness approx 12 inches/30cm. Water ingress at the front comes into the house around windows. There seems to be no pattern or logic to it, rain and high winds can drive against it for days with nothing coming in and then one day it is like a tap has been turned on and the windowsills are flooded. Woodwork around window frames is ruined. Upstairs windows do not leak but there is evidence under the floor of water entry. Builder has tried using hose on house walls, around dormer window and nothing definitive has come of it. He's been working on it for months and now and I need a fresh look at it. All help/opinions gratefully received.
Any cavity? You sure? If water suddenly pours in at seemingly peculiar times, then that indicates that it isn't due to directly penetrating damp, but instead is building up somewhere - where there has to be a void of some sort - and then 'overflowing' or syphoning out in one go. Fair chance this is up in the roof space; water could be coming down the roof felt (having gotten past the roofing or ridge tiles) and is pooling on the wall top before finding a channel down to the window. Your actual wall could be perfectly fine and quite impervious to the driving rain. (All guesswork, tho') No harm in calling other builders out, especially very local ones and the more 'time-served', 'old-school' types. There is someone out there who knows these types of houses, and will know what the cause is. He'll feel it in his water.
Hi Devil's Advocate, thanks for your reply - I'm pretty sure there is no cavity in the wall from what I have been told about how the walls are built. Anything and everything gets thrown in from bicycles to bed frames and large rocks just to fill up the space and reduce the amount of concrete going into the construction. Of course every house can differ in some way or other so until my builder gets the woodwork off from around the windows (hopefully on Monday next week) then I won't be able to confirm a cavity or not. I agree with what you are saying about water build up and it overflowing or syphoning, I just can't picture it in my mind's eye how this is happening in a "solid" wall. Roof space looks dry and ok, have been up when insulating, very basic construction of timbers, tar and tiles. Good point about another opinion - the guy I have looking at it is a local and has experience with this. There are many other local builders who have served their apprenticeships with this as part of their training so there will be a number to choose from.
There is obviously a 'void' somewhere - the water is clearly gathering somewhere before is comes out in a rush. Where that void is I dunno - could be a unexpected gap (bubble!) in the middle of the concrete. I'm guessing there is still a lintel embedded above the window opening? In which case, my guess is that the water is somehow pooling above or on this.
ah you'd be surprised - we've converted and incorporated quite a few existing WW1 utility structures up here, they knew how to do mass poured structures back then - there's usually plenty of steel left, but it's either disappointingly weak or frustratingly strong - as is always the way
some were structures designed for housing, others had a slightly more protective function - quite unpredictable strength whatever the thickness's - they certainly weren't short of cement
Lets hope if it has steels that it's not suffering concrete cancer, though if the steels have rotted out in places, it could explane water coming in, down the hole left where the steel was, if the roof is leaking and letting water in, it could build up to the point it flows into the hole and through the wall.
My guess is that some of the rebar has gone and there will be voids in the concrete. Only real way to tell is to have a dig about but that will create more problems. Some sort of X-ray machine or perhaps approach a local Uni Civil Engineering department and see if they can help with some such equipment. I'm know that this problem has been met before but in utility buildings such as Power Stations, Hospitals and multi-storey car-parks. Getting a Tech College or Uni interested will give you access to a lot of technology and expertise. Just a thought.
Morning one and all - thanks for the suggestions, some interesting ones coming through. Elsewhere in the house in a former external wall (extension built on so the external wall became an internal wall) there was iron reinforcing (which I recall was pretty heavy gauge metal), but I can't be sure about the suspect wall. My builder reckons there's no concrete cancer as the outer dashing is still sound and solid. I'll take a look at the local uni see what they can do. Have just got the woodwork off from around one of the windows this morning, concrete wall is wet and wood packing is like a sponge in some places. The inner facing wall is dry on the surface The underside of what would be the lintel is wet From the left it is wetter and dries out towards the right following prevailing wind direction (coincidence?) Builder found a hole at dormer window level not properly filled with mastic and has corrected this Thanks once again for help.
Concrete cancer starts in the middle and works it's way out, so I'm not surprised by the outer skin of dashing appearing sound.
I wonder if some of the render has got a number of voids behind it and the poured walls - which it's not bonded properly, or over time it has come away easy to find by tapping - there'll be a very distinct difference in the sound when you find a section that's hollow behind it would only take a small fracture, possibly not even visible, to enable enough rain to track through and become trapped between the render and the wall
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