Advice on new garage roof leaking....

[withnail1969]

We've had a lean to garage constructed. It has a polycarb roof running into a wooden valley gutter. It's quite long (6-7 metres) and runs around next doors chimney breasts.
The valley is flat I would have expected it to slope to help the water run off.
The main problem is that it leaks. The felt has been reapplied and built up so it's leaking less but still not watertight.
I'm uneasy about settling the bill (we've paid half), it looks like a patch up job and I'm not convinced even if it stops leaking that it will stay watertight.
Any advice pls?

 

[Regencyroofingipswich]

First bit of advice, dont pay another penny until it is watertight, you are paying for a roof which is supposed to keep water out ...not in.

If you can post up some pictures tommorrow it would give us a better idea of whats going on, sounds like a builder has been trying to do a roofers job again .

 

[withnail1969]

Thanks. He is actually a roofer. He's done bits for us before and always been fine. Will sort some pics later tomorrow.
Cheers

 

[withnail1969]

I've uploaded some images

//www.diynot.com/network/withnail1969/albums/

 

[htgeng]

one of the regular roofing guys will confirm, but that 'valley' should be done in lead if you have any hope of it being watertight.

 

[Regencyroofingipswich]

Very hard to tell. For starters it should never have been built without a fall on it.
If it is dead flat and has not had a pitch built into it theres a good chance even with an accidental degree of it falling the wrong way that it could all be running up to one end and actually having the water build up so high that it is coming in over the top of the felt even if it is sealed correctly.

Was three layers of heat applied felt used all with staggered joints ? I hope so ! if he has used all three then i dont reckon his joints are up to much.

Personally a tricky little box gutter like that should never have been done in felt in my opinion and although im not usually a fan of it i would have recommended the gutter be lined with a grp fibreglass roof covering that has no joints in it, perhaps if the problem persists you could knock enough money off your current roofer and get another competent roofer to lay it for you in grp ?

 

[Regencyroofingipswich]

Lead would have been ideal as long as it was stepped at every 1.5m which may have been tricky on that roof design, also would be concerned about the weight of it on a relativley lightweight structure

 

[Mw Roofline]

It's a shame the glazing bars don't marry up with the timbers (perhaps this is because the timbers are quite wide )

I'm afraid that box gutter needs re-doing if it leaks, either in grp or rubber. We had a customer exactly like you and we did it in rubber but the builder had to take the whole thing off for us to do it.

I don't do felt and never have done but wouldn't it have been better to put the felt in longer sections?

I'm sure the roofer has done his best but unfortunately it hasn't worked

 

[withnail1969]

Very hard to tell. For starters it should never have been built without a fall on it.
If it is dead flat and has not had a pitch built into it theres a good chance even with an accidental degree of it falling the wrong way that it could all be running up to one end and actually having the water build up so high that it is coming in over the top of the felt even if it is sealed correctly.

Was three layers of heat applied felt used all with staggered joints ? I hope so ! if he has used all three then i dont reckon his joints are up to much.

Personally a tricky little box gutter like that should never have been done in felt in my opinion and although im not usually a fan of it i would have recommended the gutter be lined with a grp fibreglass roof covering that has no joints in it, perhaps if the problem persists you could knock enough money off your current roofer and get another competent roofer to lay it for you in grp ?

Roof is dead flat. I don't know how many layers of felt were used.
I don't know of grp fibreglass, is this used often and is it expensive? I'm not sure how easy it would be to find a roofer who would take on a botch job.

 

[withnail1969]

It's a shame the glazing bars don't marry up with the timbers (perhaps this is because the timbers are quite wide )

I'm afraid that box gutter needs re-doing if it leaks, either in grp or rubber. We had a customer exactly like you and we did it in rubber but the builder had to take the whole thing off for us to do it.

I don't do felt and never have done but wouldn't it have been better to put the felt in longer sections?

I'm sure the roofer has done his best but unfortunately it hasn't worked

Our first concern was the timbers not matching up but now it's the least of our woes!
The felt underneath is in longer sections, the smaller sections were added on when it starting to leak.
They are coming back tomorrow to build in a slope and re-felt the roof.
Is there any point in them doing this or should we put a hold on it?
He is embarrassed and has apologised, I don't think he's a conman but i'm not confident he can fix it either....
Thanks everyone.
PS I've added another photo, the final run at the end after the chimney breast doesn't seem to have the lead flashing, would there be a reason for this?
Update: We've told him we don't want a felt roof. He's coming round later with a roofer who does rubber roofs. He's made it clear he hasn't budgeted for a rubber roof. Should we be expected to pay extra now, he never told us he was quoting for a felt roof.

 

[Regencyroofingipswich]

Even if you strip the felt out when and redo in rubber there will still be standing water in the box gutter which isnt ideal if a fall isnt put onto it.

There will still be some joins in a rubber membrane but i think it is more suitable than felt.(still think grp would be miles better).

If you want to be safe rather than sorry i would strip it all out and add a fall of around 6 inches end to end and redo in a suitable material.

 

[withnail1969]

Thanks for replying.
He is now going to build a fall in, the rubber roof will be guaranteed for 25 yrs, our roofer is taking the hit on the cost so I think we will be going with this option and hoping it all works out.
Thanks again for everyone's advice.

 

[Regencyroofingipswich]

Sounds like a positive result.

At least the roofer was honest enough to get it sorted.

 

[SASroofer]

Bit late, but its hard to see from the pics if the felt is poorly laid. I'd be more concerned with the lead flashing, as its been pointed completely with lead mastic, which is poor. Should be a mastic seal at the back of the chase, then a send/cement mortar to finish. Also did he tuck into the chases deep enough? Minimum 25mm.

Try and take some pics of his work as he does it (or ask him to)

If the felt has been done properly it wont matter how flat the gutter is.