We have a mysterious leak in our new extension and we're struggling to work out what's going on. I'm not convinced posting photos will help with understanding what's going on as the leak doesn't appear to be coming from anywhere visible so there's nothing exactly to take photos of, but to give some back story, we bought a nearly derelict house. The whole house was refurbished and a new flat roofed extension with a parapet wall and coping stones was added to the rear as well as all new render been put on the entire house. We realise now, a year on, that the builders have proved to not be particularly good, and have now quite literally vanished, so we have no chance of getting them back to rectify anything. We have had a lot of leaks so far (mostly due to using insulated breathable lime based render and finding out we needed to coat it with breathable waterproofing sealant as we're in an exposed position), but have managed to rectify all the others except this one, which we just can't work out.
When it rains heavily, water is literally pouring down the wall in the new extension, in the corner next to the steels that have been put in to support the new opening. Its coming in directly under and slightly to the side of the steel, though not under the ceiling itself, which is higher (the steel drops down by about 30cm from the main ceiling). On the wall outside in the same vicinity there is a point where a soil pipe exits the wall so our first job was to seal around the pipe exit hole with silicone. This didn't help. There is an airbrick that ventilates the warmdeck roof level with the point the water enters, but about 45cm further along the wall. Above there is a parapet wall with coping stones. The render seems cracked around the point where the coping stones meet the render. Sky also ran their cable along this join. We siliconed along the crack, and moved the sky cable and it seemed to stop leaking for a few days so we thought "halleluja, we've fixed it!" But yesterday it leaked again worse than ever (literally a river pouring down the wall) and now i'm wondering if its just to do with the direction of the rain. The coping stones are a lot higher than the leak (the parapet is about 30cm above the flat roof, and the steel about 30cm below) and there have been no leaks at ceiling level, only lower down near the bottom of the steel, but I am aware that water travels in mysterious ways and may not be leaking where the water is coming in. There is no flashing I can see where the coping stones meet the wall, but as its rendered, its possible is is under the render. The render of the wall has been heaving waterproofed with Surfapore C three times now. I can't see anything else it can be.
When it rains heavily, water is literally pouring down the wall in the new extension, in the corner next to the steels that have been put in to support the new opening. Its coming in directly under and slightly to the side of the steel, though not under the ceiling itself, which is higher (the steel drops down by about 30cm from the main ceiling). On the wall outside in the same vicinity there is a point where a soil pipe exits the wall so our first job was to seal around the pipe exit hole with silicone. This didn't help. There is an airbrick that ventilates the warmdeck roof level with the point the water enters, but about 45cm further along the wall. Above there is a parapet wall with coping stones. The render seems cracked around the point where the coping stones meet the render. Sky also ran their cable along this join. We siliconed along the crack, and moved the sky cable and it seemed to stop leaking for a few days so we thought "halleluja, we've fixed it!" But yesterday it leaked again worse than ever (literally a river pouring down the wall) and now i'm wondering if its just to do with the direction of the rain. The coping stones are a lot higher than the leak (the parapet is about 30cm above the flat roof, and the steel about 30cm below) and there have been no leaks at ceiling level, only lower down near the bottom of the steel, but I am aware that water travels in mysterious ways and may not be leaking where the water is coming in. There is no flashing I can see where the coping stones meet the wall, but as its rendered, its possible is is under the render. The render of the wall has been heaving waterproofed with Surfapore C three times now. I can't see anything else it can be.
