Flat roof above bay window not draining - can I add a slope? Information, help and advice on maintaining, installing and repairing a flat roof. Post your questions and view answers here

[the_duckchild]

Hi - as you can see in the attached images we have a small flat roof above a bay window in our (Edwardian) house, which is not draining water.

The left hand side of the roof drains into the lower portion OK, but the water then pools up. The drain was previously blocked, and we had this cleared, to little effect on the pooled water. Following a heavy storm I think this has probably contributed to a small leak in the room below, and I would like to make sure this roof is draining correctly.

I think I need to add additional slope to the lower portion of the roof, and perhaps reseal around the edge with flashband, but I am not sure how best to go about rectifying the slope?

I'm hoping somebody may be able to help with a suggested solution

[stoneyboy]

Hi the_duckchild,
You may be better off forming a new drain hole at the lowest point, this feeding out to a new section of gutter around the bay.
Increasing the levels of the flat part may increase the chances of water ingress because the upstand will effectively be reduced.
Regards S

[the_duckchild]

thank you - it's really hard to tell where that is currently as the water seems not to be moving very much at all. I think we may need to reseal around the edge of the roof in any case, so I am thinking this is moving towards being a job for a professional.

especially as it is on the third floor.