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Looking for advice on replacing or repairing my shed roof. I live in rainy Lancashire, and I might have got away with this for a few years as the opposite house had some evergreens which were cut back last year exposing my shed roof more.
I knew I had a slight leak in the back corner over winter (and put this down as an ignore until
Summer job), but with it hammering all day it’s coming in three spots today. The rear I thought it was getting in on the overlap or at the edges so covered it with a spare bit of visqueen I had which has helped but not stopped it totally.
It would be classed as a “flat roof” as its 9.5 degrees pitch. It’s shingles and I don’t know if it has an underlayer (internet says it should) but there is no overlap at the ends where the barge boards cover it up. I thought perhaps my leak was coming in here and running along the top of the shingles felt but I have more than one leak now.
The shed itself is an estimate 5-8 years old and is substantial construction. The roof is tongue and groove and I assume pressure treated pine. The water can be seen to drip in along the grooves.
As new shingles and underfelt will be a substantial investment, would I be best to go for a single piece EPDM over the whole thing?
Cost would be an estimate £400-500 (5x5.5m approx). But underfelt and shingles might run me to £200-300?
I’m leaning towards the EPDM as it’s done for life then, a heavier duty 1.5mm as there isn’t that much cost wise in it compared to 1.2mm. I’ll need some new trim at the sides as there is no gutter and it just sheets the rain off at the minute.
Any recommendations either way, obviously I’m planning for the bank holiday at the end of the month!
I have recently re-roofed my shed with Coroline sheets replacing 10 year old felt. I would guess it would be cheaper than EPDM
https://www.arielplastics.com/en-gb/products/bitumen-roofing-sheet/coroline-sheet-and-accessories.aspx
I was quite a lot more expensive than re doing with felt, but it has a 15 year guarantee (for what that is worth) and was easy to install
I used edpm on my shed. easyish to fit, but I'd built my roof to support the weight of a person. If your roof isn't that strong it'll be trickier to get it flat. you need to budget for some glue, and I wrapped mine all around the roof then battened it upwards on the underside of the edget to hold it tight. 4 years later there's no sign of any wear.
I bought the sheet off a respectable-looking ebay vendor, it was smaller but nothing like as pricey as your suggesting - maybe £100 for a sheet half the size?
Hmm I’ll have a look on eBay/scout around for alternative EPDM. I think the cost ramps up when you increase the required sheet size.
The corrugated sheeting looks a little too agricultural for my area I think, but it wasn’t something I’d considered.
The roof is most likely strong enough to sit or stand on, the tongue and groove is quite thick and the joists are pretty big, perhaps 50x150.
EPDM is great. I'd just get the standard 1.2mm stuff - it's pretty tough, esp if it's just for a shed. Note you can get different types of epdm, the stuff that is building reg approved or the stuff that isn't for sheds - quite a price difference. I found this out after doing my workshop! I think the cheaper stuff is called shedcover.
Caveat - total pain in the ass if you can't stand on it to fit it. Also note that a roll of epdm is pretty heavy so it's a two man job to get the roll on the roof.
I live in rainy Lancashire as well and I have recently re-roofed my shed with metal corrugated sheeting replacing Coroline sheets. The Corolin sheets lasted over 10 years and the come in different colors.......
The Tarp I've been using a felt replacement for the shed roof over the last year or so has ripped off in the night due to the winds......
check prices for epdm pond liner it might be cheaper
I also live on the rainy Lancashire Cumbria border, and have successfully re roofed my shed with this
https://www.pondkeeper.co.uk/pond-liner-4m-x-4m-40-year-guarantee-plus-underlay/p2658
It's easy to throw on top of the roof, pull it taught and screw/nail the edges down.
It's not really designed for roofing, but is waterproof (being for ponds obviously)
Goes on in 30 mins. And lasts for a few years before it needs replacing.
I started using it in the same scenario as you are in, original roof was full of holes and needed it to be watertight a.s.a.p.
Had a proper look today. There is no base layer of felt which there should be for a roof of this pitch.
The rain can wick up from the ends as it runs off and the boards are a little damp at the ends here, up maybe 50mm.
The felt edges don’t have anything protecting them so I think the rain can just enter here and travel along the top of the shingles underneath the surface. If I did have a sub felt it would wrap around the edges and protect this.
I’ll pull the end boards off the shed and clean it all up. Maybe paint with some roof repair to stop any further penetration over the coming weeks while I research/wait for payday!
It’s daft as all the shingles have to come off to replace but if it was subfelted originally I am sure I wouldn’t be having this problem and would get 5-10 years more. The PO had it built and wasn’t much for DIY so maybe wasn’t aware or it was a Friday afternoon roof job...
@tarquin - Also looking at getting the roof replaced on my shed, which is smaller and not as heavy duty as yours.
Have you seen the metal roofing sheets you can get, tile effect ones look pretty good? Considering putting one over some extra insulation, with a breather membrane and air gap, as the big sheets should be pretty robust and the green isn’t too objectionable.
https://www.britmet.co.uk/pantile2000.asp
Great timing with this thread, I need to sort mine out this year and have been wondering what to use as I don't want to use felt again.
The link for the pond lining looks good cheers. I might message you for some advice bigalid if that's ok?
Cheers.
Another +1 for EDPM. Replaced a large flat shed/garage roof over the summer and it's spot on. Just leave it unfolded for as long as possible to let the ripples settle from where it was folded.
Anyone used proper tiles? I have loads of original double romans from our reroofing to give it a go on a 3x10 bike shed. Suspect it will be quite heavy.
@csb - Did a rough calc of over 350kgs for a 8’x10’ apex shed at about 9m2 of area and a 40kgm2 roof tile.
Likely need to reinforce the roof, walls and joints unless it is properly sturdy as is.
Thanks for the calculation. It's one of those pent roof bike sheds so the roof is well supported and the build is sturdy. I shall give it a go.
Lucky you, should outlast the shed if you do it well! 👍
Check the angle first though as they likely need a decent pitch, even if you use a good underlay.
From Google - Double Roman - 25° Smooth (75mm headlap) 30° Granular (75mm headlap) 22.5° Smooth (100mm headlap)
That was what my friend suggested for mine initially, but it’s not strong enough and only ~14 degrees.
Galvanised corrugated sheeting. I have it on both the shed and the garage. I got min for about £11 sheet off ebay.
Remove shingles and screw down to ply. Strong, lasts for years and recyclable.
Let’s see if that works. Took the end boards off to inspect which shows that all they do is hold water against the roof! As you can see, no underfelt, so it just directs water under the shingles!
One board is rotten so only really good for a template. The other can be saved.
As an interim I painted the ends with flat roof repair with the plastic fibers to stop water just blowing and wicking into the roof.
If the end boards are trash or not I’m not 100% sure, they weren’t too soft, perhaps I could take 10mm off with a circular saw all the way up.
I can’t believe it was built professionally and someone thought that was acceptable.
@kimura54321 thanks again for your tech input! I got some roofers fabric cut offs from a skip so will tack that down first, then go with the 100mm overlap. It's against the house wall so well protected, it'll be reet!