Gutter in flat roof

[Justanothergeordie]

I have a flat roof extension with sliding glass doors at the end. Projecting out about a foot above the doors, the roof has a built in gutter. The projection then comes down above the door frame at an angle. When it rains the gutter fills and works as expected but occasionally if it rains very hard, any rain hitting the projection or the roof beyond the gutter, runs down the angle towards the door. Over time this has rotted the joint and rain sometimes gets inside.

I'm in the process of sanding, filling and painting the projection again but I need something to catch the drips at the end of the projection before it hits the slope. I wondered if anyone here might be able to suggest something? It's quite a wide extension, so a strip of wood suitably fitted on and sealed but hanging down slightly might work but wondered whether some kind of silicone strip on a long roll, stuck on and properly sealed may work? I don't want to bodge it up and have to re-do it later so any help welcome...

I've attached a rubbish side elevation drawing to help explain, sorry it's so bad!

 

[freddiemercurystwin]

Got some photos?

 

[Justanothergeordie]

Try to ignore the mess, it's all being sanded/replaced/filled in/repainted etc to make it watertight. Just wondering about the drip edge and how best to tackle it... thanks for the reply

 

[Mr Chibs]

What about something like this, not cheap, but might give you an idea of something to do.

Aluminium fascia

 

[freddiemercurystwin]

Is the roof finish epdm? What is the grey material and what height is the fascia?

I would say stick an epdm drip flashing on the fascia and then lap the edpm over it.

Something like this:



eg https://www.roofingoutlet.co.uk/products/metal-edge-trim-for-firestone-epdm-2-5m

 

[Justanothergeordie]

Thanks for the replies both.

Yes it's a membrane called XTEVA and it lips over the projection. I'm nervous and peeling it back and fixing something like the drip flashing under though I'm sure that's probably the best way to do it.

I think I was hoping there would be something like you've suggested but much smaller which just tucks under the EPDM a tiny bit and is tuck down like in the drawing attached. Plus something on a long roll so it's not in sections as it's 6.5m wide. That would mean some kind of plastic material I'm guessing?

 

[freddiemercurystwin]

You wouldn't peel any membrane back, you'd stick the flashing on top of the existing membrane, then dress a new strip of membrane over the join, you would just overlap each length of trim by say 50mm where they join.

 

[Justanothergeordie]

Sorry, I misread – I think I'd still like to steer clear of any additional membrane as it has a guarantee on it which is void if anything is done to it. And with my history, it probably would...!

 

[freddiemercurystwin]

Well they should have fitted a proper trim instead of leaving you with that mess, get them to fix that under their guarantee. Get their rep out?

 

[diy_fun_uk]

Could you not just create a channel on the underside e.g. with angle grinder a couple of inches from the outer edge? This would stop the drips reaching the door. Referred to as a drip channel/groove.

 

[Justanothergeordie]

@diy_fun_uk that sounds more like the kind of solution I was after... something less noticeable. Do you think stick a thin piece of beading underneath the overhang just before the groove would help too? I'm not sure the overhang is very thick so a groove may not work.

@freddiemercurystwin I know they should have but the build was 11 years ago and they'll probably say I haven't taken care of it.

 

[diy_fun_uk]

@diy_fun_uk that sounds more like the kind of solution I was after... something less noticeable. Do you think stick a thin piece of beading underneath the overhang just before the groove would help too? I'm not sure the overhang is very thick so a groove may not work.

@freddiemercurystwin I know they should have but the build was 11 years ago and they'll probably say I haven't taken care of it.

Ah right so you think if you were trying to create a groove a few mm deep it might go right through the material?

In theory yes, anything you stick on that creates an edge will stop the water reaching the door. Some form of beading, securely adhered, would do the job. If you have any way of finding out how thick the material is though and were confident you weren't going to compromise it by creating a channel, the channel would be my preference.

 

[Justanothergeordie]

@diy_fun_uk thanks for the help. I'll look into that and thanks for the help all.

 

[catlad]

Ask the architect what the solution because it looks like a design flaw to me!

 

[cdbe]

Someone has nailed a cable on the outer face without apparent issue so just fix something there to form a drip. Off the top of my head, something like a trimmed down felt tray would do it. Remove the cable and tuck it right under that bit of roofing material overhang where you've put that little red arrow on your drawing.