Leak coming in around roof light EPDM issue

[nmh]

Roof only about 18 months old. New rear extension with roof lights. Water came through ceiling light this weekend and I took pictures shown. Looks like builder didn’t lay EPDM up to lantern correctly. I worry that the wood behind is moist and covered in old adhesive stuck there. Builder awol. Sent pictures to a roofer who said only thing that will take is cutting EPDM back 100mm and laying felt fascia onto the wood with bitumen. That’s ‘only thing wood would take’. More mastic would just come away. Instinctively didn’t think felt and EPDM went together but I’m not a pro. And advice much appreciated…

[Redbeard]

Gut feeling is that if it is EPDM it needs fixing with EPDM by someone experienced not just in new installations but in remedial work. Nothing wrong with bitumen/felt per se but I wouldn't mix it with EPDM. I cannot 'place' pic 2 w.r.t pic 1, BTW.

[jack]

34 minutes ago, Redbeard said:

Gut feeling is that if it is EPDM it needs fixing with EPDM by someone experienced not just in new installations but in remedial work. Nothing wrong with bitumen/felt per se but I wouldn't mix it with EPDM.

 

Agreed. Stick with EPDM, it's great stuff when used properly. 

 

12 hours ago, nmh said:

More mastic would just come away.

 

That's likely true. As far as possible, membranes should always be designed to direct water over and/or away from junctions, rather than relying on sealants.

 

In this case, it looks like the orange circled section of the extrusion is an overhang:

 

 

If that's the case, then I suspect the EPDM should have been lapped over the channel with the screw in it and tucked up and bonded into that recess. Can you check the rooflight manufacturer's installation instructions?

 

Don't worry too much about damage to the wood. It's been a dry summer for most of us, so the wood was probably well and truly dried out before the latest rain. A winter or two isn't likely to have caused permanent damage, especially given the seal was probably functional for a lot of that time.

 

If you're at all handy, this is doable without professional help.

 

In the short term, I'd get hold of some decent waterproof plastic and cover the roof light with it, leaving enough at the sides to hang down and cover the area with the leak. Tie it down and leave it like that for a few weeks for everything to dry out.

 

In a couple of months' time, and ideally after a dry, hot couple of weeks, you can install the EPDM permanently. Your rooflight manufacturer can probably point you in the direction of how this should be done, or there are loads of Youtube instructional videos (or ask here when you're ready). Given that the leak is only at the top, you don't need to worry too much about anything other than making sure you get the top edge well tucked up and bonded into the recess, and that it extends down past the sloped part.     

[Temp]

Advises against using asphalt products on EPDM..

 

https://www.elliottroofs.com/article/steps-to-repairing-a-patch-of-damaged-epdm-roofing-membrane

 

[JohnMo]

Isn't the correct way with EPDM to take a skirt up from horizontal to vertical and up and under any drip ring around roof light?

 

All seams either heat welded or correctly bonded. Difficult to tell from images what they did. My roof is all mechanical fixed and heat welded seams. No mastic or glues.

 

What the roofer is proposing is a bodge at best.

[jack]

2 hours ago, JohnMo said:

Isn't the correct way with EPDM to take a skirt up from horizontal to vertical and up and under any drip ring around roof light?

 

Yes. I think the main issue here is that the roofer stopped the skirt when it reached the first lip, which is short and doesn't have an overhang. The skirt should have continued up higher into what looks like it might be the actual drip trim above the screw (see circled bit in my post above).

[Nickfromwales]

4 hours ago, JohnMo said:

What the roofer is proposing is a bodge at best.

A bodge with a very short life expectancy at that! Terrible advice.

 

@nmh You could just bond some offset PVC trim LINK to the flat of that aluminium profile to act like a skirt, and that will stop the leak. Use clear CT1 and take a load of pics to show prospective new roofer(s). Wait until dry weather and get it sorted properly. 

 

Looks like a mash of profiles and thicknesses, where the wood should have not been recessed in under the aluminium, as that has made for a very difficult detail for the roofer (on his mothers side) to get right....

[Tetrarch]

That detail looks very odd. My spec was 100mm of waterproof upstand as a minimum (see below)

 

I used EPDM rather than the architects lead spec and they (generally) don't use 45-degree flashing anymore for EPDM. I would wholeheartedly agree with the other critics of your roofer's advice. In my experience traditional felt roof guys are always only really happy with felt, some rave about liquid coverings, but most rail against EPDM. I'd get an EPDM specialist to have a look at your particular install and go from there

 

Regards

 

Tet

 

[nmh]

Really appreciate all the help and advice. Given me lots to consider. Basically the original builder bodged the EPDM around the roof light. I'll look for an expert to sort. 

Any recommendations in the SE22 area of London (East Dulwich)? 

[Nickfromwales]

7 minutes ago, nmh said:

Really appreciate all the help and advice. Given me lots to consider. Basically the original builder bodged the EPDM around the roof light. I'll look for an expert to sort. 

Any recommendations in the SE22 area of London (East Dulwich)? 

Maybe start at the BM and ask for contact details for the rep of the membrane supplier. Pick their brains for a top local installer.