Another flat roof drain problem...

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24 Jan 2013
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I've attached a picture of my recently replaced flat roof. It looks as if a square has been cut into the insulation to allow water to get to the downpipe.

Problem is that in heavy rain the square leaks v slowly through the ceiling below it.

I believe this is for two reasons. One - prevailing wind blows leaves into the square (I had just cleared them before this photo). Two - the square is a bit too flat. Not completely flat, but water does pool a bit.

I only have access to the roof via an elderly neighbour so I can't go up there all the time to clear the leaves.

If I ask the roofer to make an adjustment, what should I ask? Could he add something more slopey into the square and seal it against the existing felt?

The gravelly stuff in the square is kinda loose. Not sure if this has an impact.

View media item 84448 [/img]
 
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The mineral felt cap sheet appears to be degrading and losing its mineral grit. Also, to my inexperienced eye, that is not a new re-roof. Its a kind of patching job.

The chute leading to the hopper head should be in lead, with a wider gutter, and altogether be better designed. The roof water should always be falling ie. flowing down, not coming to a bump just where it goes into the chute.

If you post pics from the hopper head, and across the main field of the flat roof perhaps more accurate advice could be given? I'm wondering if the whole roof from joisting up to cap sheet has been wrongly built in the first place?

Given that you have penetrating moisture then you must do something or you will end up with some kind of fungal decay in the roof structure.
 
The outlet through the parapet wall should be enlarged and as ree stated the outlet should be fabricated in lead.
 
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