Whilst putting a fresh coat of wood preserver on my Mothers fence recently I checked out the roof on her garden hut. It was custom made several years ago by a now retired ‘shed builder’ and bolted together by yours truly. The felting on top of the single slope is now cracking in various places, and there are several 2p sized holes in the outer felt, but no sign of water ingress on the internal roof timber. It all seems bone dry.
Rather than leave it, it’s a simple job to refelt it. Should i fix the new felt over the old, and if so paint a layer of bitumen over the old felt first? Or take off the old felt on a dry day, paint on some wood preserver ( plus anything else?) before fitting new felt with a 3†overlap under the side boards?
Any advice gratefully received
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Remove the old felt. Check the timber decking and refelt. Not need for wood preserver or anything else. Wood wont rot if it is kept dry.
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I would strip it all off and lay new felt. If you overlay then it might not adhere properly and be blown off in due course. I renewed mine not long ago and didn't find it too onerous as an oldie DIYer. The roof width was too long for my felt so I lapped it, nailed the bottom layer using short galvanised nails and used a black gunge to stick the top layer over the 30cm lap. I then left a few house bricks on the lap overnight to make sure it stuck well.
I made a mistake and didn't leave enough drip length at the eaves (I thought an inch or a couple of cm would be enough) and water has crept up it to very locally dampen the roof timber at the edge. Next time I'd leave a good three inches or so hanging over.
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We have a row of small sheds (around a 1.5 meters high) proper sloped roof and sturdy roofs. Cattle from the neighbouring field had been chewing at the edges (!) - Bought a roll of felt used it to overlap the existing - glued it down with proper roof felt adhesive then nailed it in place, then "painted"it with the thick glutinous adhesive. Survived all of last winter's storms and crap. The adhesive survived the blistering sun (south facing) all summer. Had though of stripping it all back but the "repair" should last years (cattle dependant)
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Many thanks for the informative and speedy replies. So far it’s 2 v 1 in favour of stripping off the old felt and fixing new. As stated, all seems in order from an internal shed roof inspection, but it will have to wait a couple of weeks....taking my old mum to visit her dementia afflicted sister in ‘the home’ tomorrow and after that depressing day I always need a few early door beers with chums in my local.
Warmer Canadian climes beckon on Tuesday. Glad I didn’t take up the invite from my northern CA based friends to visit and stay with them for Thanksgiving. Truly awful fires which we’ve all seen on the news.
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What they all said.
In addition. To make the felt easier to bend, and reduce the risk of cracking as you fold it around eaves, store the felts rolls somewhere warm before use. It also helps if you choose a sunny day, even in winter, to keep the felt flexible.
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Remove all the old felt. Pulling loads of the felt nails is a bit of a pain.
Replace with good quality felt.
I replaced mine with bitumen corrugated sheeting which has outlasted the felt and shows no sign of deterioration.
www.wickes.co.uk/Products/Building-Materials/Roofing/Bitumen-Corrugated-Sheets+Trims/c/1000253
There are also other equally good suppliers :)
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You remove all old felt, moisture will be trapped under it.
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Have 3 x mancaves, recovered 2 of them, always taken the old stuff orf. I'd use this next time:
www.agriclad.com/product-category/products/9
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My 7 x 5 shed was in place when I bought my house 40 years ago.
I have stripped and re-felted the roof a few times.
Overlapped the felt plus black glue stuff and the galvanised nails.
Do not buy the cheap "shed felt" but choose a thicker option.
A simple cheap modification I did to my shed to prolong its life.
With age the wood shrinks and the nails get larger holes so stability reduces
( The shed has a sloping flat roof and an offset door in the 5 foot end.)
I bought a sheet of three ply and cut it to shape for the non opening part of the 5 foot end.
On the inside of the shed I screwed it in place thus restoring some rigidity for very little cost.
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I have re-roofed a shed using corrugated bitumen sheets - available in a variety of colors. Use the correct fixings, and if there are inadeqate structural members in the existing roof add some internal battens, Guaranteed to be water proof and it will see you out. Also useful in exposed conditions where wind maybe a problem. Not the cheapest solution, but will look good. For the top use the correct profile pieces and cap off with either the proprietary ridge capping or use overlapping ridge tiles. Felt is dirty, messy, and never looks as good as a job done by a 'professional' roofer.
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>> Felt is dirty, messy, and never looks as good as a job done by a 'professional' roofer.
I found it very simple to install.
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>> I have re-roofed a shed using corrugated bitumen sheets - available in a variety of colors.
We've done the same with ours. Everything is still sound as a pound some 10+ years on (touches wood). Far more durable and lasts one hell of a lot longer than felt.
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Last year I re-did my allotment shed roof, stripped the old, cut new to length, then luckily the council were re-doing some pavements nearby, so for a slight bribe I managed to get two buckets of hot tar which I slopped generously on the roof and applied the felt when it was still hot, then I battened the roof every two feet, and slopped the rest of the tar over them. Wish I'd had the time to do the sides as well as they will probably rot out long before the roof ever does!
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Thanks for the bitumen sheet tip. Not come across those. Looks like a reroof of our shed using those for our materials might come in at about a grand or so, at Wickes prices, though it's probably nineteen times that to take away the existing asbestos.
Last edited by: Crankcase on Tue 13 Nov 18 at 12:03
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I checked out ours earlier. Still a very sound repair, no water damage - the bitumen based adhesive with which it was glued down was also used to seal the joint between the new layer and the existing roof felt shows signs of bubbling - down to the very hot weather last summer I guess - roof faces south.
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Refelting a garden shed roof - CGNorwich
