GRP gully leaning in the wrong direction

[opps]

Hi all.

A customer has a parapet wall with a 1000mm long GRP gully which should run down to a hopper. At the non hopper end is an old chimney. Unfortunately, the gully tilts in the wrong direction and the water pools at the chimney end. He says that he has a leak indoors at that point. This morning, at the deepest point, the water was about 8mm deep.

Any suggestions on how to rectify it without too much disruption. I am not a roofer and so don't want to have to lift the tiles to remove/replace the gully. Is there a super thick resin that can be used, or perhaps, could I cut some uPVC, pack it out and then either GRP over it or just seal it with CT1?



The above is taken from the chimney breast. Not visibible is the (lead) exit to the hopper. (Photo taken today and not yesterday).



The above is from the hopper end, running up to the chimney breast. Today, there was only about 3mm of water, but it hasn't rained for a while and evidently, 5mm of water had evaporated off. (Photo taken today and not yesterday).

Thanks in advance.

 

[ree]

OP,
Why have you involved yourself in doing a job like that when you obviously have no idea of how to go about that kind of work?
eg. if water was pooling & slowly draining then there's more to it than a wrong falls.

None of your suggestions will work, they will only cost the "customer" money, & future leaks so why not leave it alone & call in a roofer who is competent doing simple lead work?
Do you understand the insurance consequences for working at height?

 

[noseall]

Hi all.

A customer has a parapet wall with a 1000mm long GRP gully which should run down to a hopper. At the non hopper end is an old chimney. Unfortunately, the gully tilts in the wrong direction and the water pools at the chimney end. He says that he has a leak indoors at that point. This morning, at the deepest point, the water was about 8mm deep.

Any suggestions on how to rectify it without too much disruption. I am not a roofer and so don't want to have to lift the tiles to remove/replace the gully. Is there a super thick resin that can be used, or perhaps, could I cut some uPVC, pack it out and then either GRP over it or just seal it with CT1?

View attachment 366929

The above is taken from the chimney breast. Not visibible is the (lead) exit to the hopper. (Photo taken today and not yesterday).

View attachment 366930

The above is from the hopper end, running up to the chimney breast. Today, there was only about 3mm of water, but it hasn't rained for a while and evidently, 5mm of water had evaporated off. (Photo taken today and not yesterday).

Thanks in advance.

That looks like a horrid can o' worms.

 

[opps]

OP,
Why have you involved yourself in doing a job like that when you obviously have no idea of how to go about that kind of work?
eg. if water was pooling & slowly draining then there's more to it than a wrong falls.

None of your suggestions will work, they will only cost the "customer" money, & future leaks so why not leave it alone & call in a roofer who is competent doing simple lead work?
Do you understand the insurance consequences for working at height?

Working at height? There is scaffolding. The side flank is being pointed at the moment.

Why would upvc cut to width and length not suffice? All I am hoping to do is adjust the fall in the gully. Off the top of my head, the fall only needs to be raised by 1cm at the far end,down to zero at the far end.

The GRP was previously done by a roofer. Presumably by one that worked off a ladder.

I don't understand why uPVC, with GRP over the top will not suffice.

Can you explain why it will not suffice?

Granted, lead does indeed sound like a significantly longer lasting option, but I am not sure that there is space to run an angle grinder all the way along.

 

[ree]

OP,
Working at height means just that - how you gain access or who had previously gained access to that height is not the question.
Without going forensic & explaining to you how to construct & waterproof a parapet gully and outlet - I'll just repeat that you dont know what you are doing so best left alone.
You have not shown the outlet or how it discharges into the hopper that you mention in another post.
Gully outlets, as with any roof outlets, are always under suspicion when leaks are reported.
Neither have you shown the customer reported interior water damage?
Based on your pics, water could be entering the roof from other places including the stack back gutter?