Sagging flat roof?

Phil4432

My back flat roof over the extension is just over a year old, the old one had been leaking intermittently over a few years.

I've recently noticed that the corner where the leak was, is ponding slightly.  Its the exact area where the leak was, however there is no ingress at present.  Its about 6mm deep.  I've circled the deepest area in the photo.



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New plywood was placed in that area, as the old plywood was water damaged.


Internally, I haven't repaired the old damage caused by the previous leak yet.  So though the photos below looks alarming, it actually is dry.  Its the area directly under the area circled in the first picture.  I'll stress that the ingress issue appears solved by the new roof.

What I'm wondering is if the roof supports/rafters were water damaged and causing the roof to gradually sag in that corner?  In the past year it may have dropped slightly, as you can see from the crack where the coving and wall meet.  But as the crack was there previously, I'm not entirely sure if its worse or not.

My thoughts are simply to fill in and repaint the internal cracks and then just keep an eye on it.

But if this is an indication of a more serious issue with the roof, I'd need to get on it.

Thoughts much appreciated.

FreeBear

A bit of lead flashing chased in to the wall wouldn't go amiss. It will stop water running down between the brick & felt.

plumb1_2

FreeBear said:

A bit of lead flashing chased in to the wall wouldn't go amiss. It will stop water running down between the brick & felt.

I agree with FB, plus don’t let any cowboy stick flashband on there.
If it’s always been ponding there, they should have put some tilt filets on the joists before fitting the new decking. But I guess you are not going to remove it now, so maybe apply some aquapol ( other makes available) in that area to build the level up.

Phil4432

Thanks for the replies.

The brick wall you see in the left of the picture is actually the neighbors wall, and is about 1M away from the roof.  Where my wall and roof meet, there is flashing, in the bottom left of the photo.

Could the joist be sagging?

Phil4432

Opinions much appreciated.

No signs of cracks in the walls, so fair to say this is purely roof related.