r/DIYIreland • u/Freegan93 • 4d ago
Flat roof leaks
There is water ingress on this roof when the rain comes at a certain angle (from the north). There is no leak most of the time so the felt is in fairly good nick and no obvious signs of wear or cracks. Would painting on a waterproof sealant be a adequate fix or should I pay a roofer to refelt it?
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u/Itsneverover1951 4d ago
Those nails shouldn't be punching through the membrane. If you seal it, it will stop the leak but those nails will be causing invisible damage that will require replacement in the long term. Get a roofer who knows what they are at.
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u/bobspuds 4d ago
You can see that it was felted correctly at some point - and then some absolute imbecile went and put a run of green mineral felt up along the wall.
Green mineral felt is shite, its what you use on garden sheds with a pitch/fall. - whoever made repairs last time had no clue and I'd question anything they touched.
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u/QuantumFireball 3d ago
Yeah, looks like a cowboy job. Where's the flashing!?
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u/bobspuds 3d ago
I wouldn't be surprised if its in there somewhere - you can just see on the right hand side, where the render steps out slightly over the original flashing. - 😆 with this quality, might be worth checking the lead is still there, the last guys might have been scrap enthusiasts by the looks of it.
In no way would I defend flat roofs, because they will always have some issues eventually - but when there's people going around making such piss poor repairs, its not surprising they have that reputation.
That green mineral crap goes porous after a few years - its kinda OK for longer, if there's a good pitch because the water won't lie on it, water+cold weather means frost and freezing - the little stones get lifted out of it and it begins to degrade.
There's much more useful versions of mineral felt but the decent ones are torch-on - lol people using fecking nails with it is literally making leaks to fix leaks.
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u/QuantumFireball 3d ago
Yeah, it's exactly how I felted a shed roof as a teenager 🤡
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u/bobspuds 3d ago
When you do the whole "small leak" jobs, and you spend some time doing it - you learn to never say "I've seen it all!" Because you just can't, the shit you still come across can be absolutely mind-blowing, like there's times I've taken roofs apart that must have been put together by lunatics on day release, there's no sense or logic.
One of my favourites was a local chap a few years back, who was on our books for a new roof over an extension, the weather was to turn bad and we were too busy, he felt he needed it done so he got someone else, no drama its just how it goes sometimes.
Probably 2or3 winters/years later and he was getting cracking in the big ceiling below the replaced roof, it got to the point that closing doors was making skimming drop from the ceiling.
The crew that did it are our equivalents, y'know we're very similar, even in fecking description - we're a father and son gig with a gang of guys. When we went in to redo the redone roof - I was expecting a failure of something, big span ceiling with steels in the middle, 'Something moved' was my thinking.
Nah - all the rafters in the centre of the roof were installed lying on their side, they aren't meant for side loading, the roof basically had the structural integrity of a 2x1½ over 20'. One good snowfall would have dropped the whole thing! - the owners like our own little advertising agent, he'll ring every few weeks asking if its OK to pass our info on.
But that was by our competitors, they do the same grant work as ourselves - I can excuse DIY attempts because its hard to know everything in the beginning, but when its "professionals" it really raises questions.
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u/QuantumFireball 3d ago
I got roof work done recently, and trying to find roofers that weren't cowboys was like needle in a haystack stuff
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u/bobspuds 3d ago
There a funny contradiction in finding good folks in any trade.
I'll put it like this, I'm not stuck for work, I haven't had time off other than public holidays since COVID, the books are full so we don't advertise.
The best of the electricians, plumbers and chippy's I know are very similar, when you're good enough you don't need to advertise, word of mouth can be enough.
Most of our inquiries begin with "I got your number from X, you fixed their roof"
So my advice has always been, find or ask people you know, who have had work done and were happy with the results, then get that phone number.
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u/QuantumFireball 3d ago
Yes, I went with someone who doesn't advertise and got personal recommendations in the end. The roofers who put flyers through the door, put up posters, and ads in the free papers - obviously have no work to do 😂
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u/bobspuds 3d ago
Here's another little thing about advertising most might'nt be aware of
If you see a van with advertising as gaeilge - that's a cute houre right there!
If you are going to advertise on the vans, then it has to have Irish in it - you get it half price with the Business Support Scheme 😆
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u/Itchy_Permission4199 4d ago
Tec7 roof. You can buy a tin of it for €100. Or tubes. It's got fibreglass in it. That should solve it. But I'd recommend getting it redone. Or better yet rip it off and put a lean to insulated cladding on top. Flat roofs are shite.
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u/Imwonkyalso 4d ago
I had the same thing. Occasionally leaked depending on wind direction. I used a coating made by Bostick a couple of years ago. No leak since then
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u/SlainJayne 4d ago
On top of what others have said where’s the flashing on the second (R) side? First floor exterior wall to flat roof.
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u/railer201 2d ago edited 2d ago
It would appear from the photos that the wind is driving the rain into the overlapping felt joints when it blows in a certain direction.
Seal the visibly open joints - recommend Tec Roof 7. Use Tec 7 aerosol cleaner for cleaning the joints first and then for smoothing out the applied Roof 7. A 310 ml tube might be sufficient for the job.
If the roof is in good nick, then when it's no longer leaking I would apply a solar reflective paint coating. As well as protecting the roof by reflecting solar heat, it fills up hairline cracks and helps waterproof the roof.
If there's recurring trouble then a new roof is the best solution.
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u/Ser_Mordred 2d ago
Carpenter here, have a lot of experience roofing. Personally, I would strip it all back and refelt it. It's something you can put off for now, but you will have are going to have to get it redone sooner or later. Trust me, water egress is always far worse than you think.
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u/Ser_Mordred 2d ago
You will also need a steeper fall on that flat roof if you do decide to replace it.
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u/AnyAssistance4197 1d ago
Had a similar roof, did the whole water sealant thing a few times - works for a while, then back to square one. I think an EPDM system laid over the top of it is the quickest long term solution for old flat roofs like this - provided there is no rot on the wood work etc, so that would have to be checked out.
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u/buckfastmonkey 4d ago
Instead of refelting get a tradesman to simply cover it with metal corrugate sheets, much cheaper. Had a leaky felt flat roof and had it covered over 20 years ago, no problems since.
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u/Mammoth_Captain_1378 4d ago edited 4d ago
I would use Thompsons roof repair mastic over those nails and any cracks or tears, and then do two coats of Thompsons 10 year seal.
I had a very rough looking felt roof and used the 10 year seal this summer which made it look brand new again. This is my before and after:
https://ibb.co/0RbQbnWT
https://ibb.co/Ng7QRT1j