Bitumen Felt Roof Repair

[ljemmo]

Hello, We recently got a roofer in to repair our bitumen flat roof as it had been leaking for some time and cracking the plaster walls underneath. The roofer found a long strip had a tear in that he could stick his finger in and there also appeared to be water ingress from the sky light that you can see on the left. His solution was to fibreglass topcoat round the edges of the roof and skylight to stop any potential ingress. He also put down a new strip of bitumen felt roofing (link removed) This cost us £350 for the repair.

He then suggested that we topcoat the entire area so that it all looks uniform and to prevent any future ingress. He quoted another £350 for this additional work (probably easy money...). My question is whether this should be done? My gut tells me that it's a bit weird to fibreglass topcoat over bitumen? If it is a viable thing to do then i'd imagine i could just buy a tub of topcoat for £50 and do it myself.

 

[Johnny Allround]

Do it yourself loads of bitumen based waterproofing for flat roofs. eBay about £25.00. Lots of colours for you to use.

 

[ljemmo]

So you reckon go for a bitumen topcoat as opposed to the fibreglass topcoat that the roofer has used around the skylight? Do you have an example of the kind of thing you mean?

Thanks for the help.

 

[Johnny Allround]

This stuff is all you will need. Coat the upstands for extra protection, happy days.

 

[Johnny Allround]

Just read some of the reviews on this product.

 

[ljemmo]

Ah cheers, yeah i noticed they also do a bitumen based one and a primer if needed too:

https://www.toolstation.com/bitumen-flashing-primer/p38120
https://www.toolstation.com/black-bituminous-paint/p88792

Also thompsons do this:https://www.toolstation.com/thompsons-10-year-roof-seal/p24314

Thanks again for your help - looks like i'm on the right track.

 

[Johnny Allround]

There you go ijemmo, and the money you have saved can by the wife a treat or two? Good luck.

 

[bobasd]

OP,
Maybe the Blackjack business will work - maybe not?

Thing is, if it doesn't work you will then have three different types of roofing materials on your roof - with a final smearing of Blackjack.
The roof needs (if you can get one) an experienced flat roofer to examine it - whoever built it did you no favors, there's a few things that instantly jump out esp the dimensions of the roof "skylight".
I cant see everything so I wont comment further - hopefully, all will be well.

If you have removed or intend to remove the ceiling below then do it, and then water test the roof with a hose - start low - & observe from below for leaks from where?

fwiw: are the water stains on the glazing inside or outside the glass?

 

[ljemmoOG]

OP,
Maybe the Blackjack business will work - maybe not?

Thing is, if it doesn't work you will then have three different types of roofing materials on your roof - with a final smearing of Blackjack.
The roof needs (if you can get one) an experienced flat roofer to examine it - whoever built it did you no favors, there's a few things that instantly jump out esp the dimensions of the roof "skylight".
I cant see everything so I wont comment further - hopefully, all will be well.

If you have removed or intend to remove the ceiling below then do it, and then water test the roof with a hose - start low - & observe from below for leaks from where?

fwiw: are the water stains on the glazing inside or outside the glass?

Thanks for the reply, the skylight was what the previous owners got installed and kinda looks like they sliced the top off a conservatory.

The water stains seem to be primarily on the outside but there are some black spots of mildew (condensation?) on the inside. I've also taken some pics of where i believe the water was getting in and pooling on the ceiling below: https://photos.app.goo.gl/wL192izBov2hnnPC9

It's not really rained at all recently so it's hard to see if the fix has worked. Not too keen on taking the entire ceiling down, but maybe i could drill some holes and see if water comes through after the hosepipe test?

 

[bobasd]

Thank you for the new info and pics.
The previous business about the Blackjack wont fly. I'd suggest that you leave it alone.

You now have roughly three possibilities:
1. strip the roofing cover down to boards or even joists.
2. attempt a certain amount of destructive investigation on the roof to locate the cause(s) of the leak(s).
3. open up a little below to give a clear shot at observing.

The skylight has way too large a footprint, making it difficult to deal with upstands & abutments.
The roof cover is slightly swollen here and there due to water ingress.
The dark smudges are low spots maybe ponding?
Moisture inside the roof is a fire hazard - elec device arcing.
Depending on how long the leaks been going on, a long shot is that fungal damage might be taking place in the ceiling & walls.
Two people do the hose test: one sprays & one observes.

 

[ljemmoOG]

Thank you for the new info and pics.
The previous business about the Blackjack wont fly. I'd suggest that you leave it alone.

You now have roughly three possibilities:
1. strip the roofing cover down to boards or even joists.
2. attempt a certain amount of destructive investigation on the roof to locate the cause(s) of the leak(s).
3. open up a little below to give a clear shot at observing.

The skylight has way too large a footprint, making it difficult to deal with upstands & abutments.
The roof cover is slightly swollen here and there due to water ingress.
The dark smudges are low spots maybe ponding?
Moisture inside the roof is a fire hazard - elec device arcing.
Depending on how long the leaks been going on, a long shot is that fungal damage might be taking place in the ceiling & walls.
Two people do the hose test: one sprays & one observes.

Thanks for the really detailed reply, much appreciated. I think you’re right that there’s been pooling. I suspect water had been running alongside the sides of the skylight above the ceiling and pooling at the section above the upvc doors.

we will try option 3 initially. It could be that the acrypol that the roofer has put on did the trick but need to confirm. Like you say, the electric side of things is a concern if not. Next house I buy won’t have a flat roof, that’s for sure...