Using 'Torch On' felt - without a torch !

Discussion in 'Builders' Talk' started by DIYDave., Aug 26, 2021.

  1. DIYDave.

    DIYDave. Screwfix Select

    Hi all

    My sister has a really small lean-to type storage shed, no back panel, just up against house wall
    All in good condition apart from the roof

    Was originally supplied with the paper thin 'shed felt' rubbish which unsurprisingly, hasn't lasted that long
    So, before the rot sets in, I have in my garage a roll of torch-on felt (but have no ideas why or where this came from) !

    Roof area is small, 1,430x480mm - including overhangs and upstand against the wall
    Roof deck is OSB, at the moment in good condition but with the felt decayed, damage will soon be apparent

    So, instead of buying a whole roll of felt for just a small strip as above, can I use the torch-on and either loose lay it or 'glue' it on with some roofing type mastic or stupid as it may sound, would a hot air gun work to soften/melt the backing ?

    Also wondering if I could go directly over the OSB without any underlay type sheet ?

    Just as I've got this roll anyway and Its certainly heavier than any other felt I've seen (green chippings imbedded in the surface type stuff)

    Thanks in advance for any input guys
  2. ramseyman

    ramseyman Screwfix Select

    As you've got it you've nothing to lose Treat it as a roll of heavy duty felt, staright onto the OSB with some felt adhesive under the lap as belt and braces. Best to choose the hottest day you can!
  3. billfromarran

    billfromarran Active Member

    A decent hot air gun will work,do it on a warm day.
  4. Tilt

    Tilt Active Member

    Or a lighter, a can of hairspray and a pair of heatproof gloves.........

    For the tiny area you are doing it should work a treat. Yes, sensibly on a hot day as the man says...

    Did a massive factory roof a few years ago, luckily not with hairspray though. And for any comedians, you light the hairspray to make a makeshift torch. Don't try doing your hair at the same time, Lol.

    Good luck.
  5. DIYDave.

    DIYDave. Screwfix Select

    Thanks for the above tips guys, appreciated

    Yes, get the point about using the felt on a warm day as will be much easier to manipulate, overhangs and corners especially
    Will cut oversized section off the roll and lay out flat on a warm day for couple hours or so to improve flexibility of the material

    Was having a tidy up in garage few months ago and the roll of felt had fallen over and partially unrolled - was nigh on impossible to get the stuff rolled up neatly again as was stiff as anything with the cold weather

    Also have a tin of Black Jack Felt Adhesive left over from garage roof patch up jobs so will maybe use that to bond between the OSB and torch on, instead of the hairspray idea (I'm sure that's from an ancient James Bond film isn't it) ? Will try a test piece on a scrap of board with the Black Jack

    Thanks again
  6. Rulland

    Rulland Screwfix Select

    Wasn't in Telford by any chance?.
  7. chillimonster

    chillimonster Screwfix Select

    Shed felt gets tacked on at the eves and the un-mineralized strip. Adhesive goes on this strip
    then the last bit of felt sits on that. I've used the blue bottle torches on such felts, it is good
    but if you need to renew the felt for whatever reason it is extremely hard to remove from
    the OSB. And there is the risk of setting light to something/the bottle rolls down the roof.
    Some people say tacks are self sealing so can go through top sheets, I avoid it unless no other
  8. DIYDave.

    DIYDave. Screwfix Select

    Thanks for your input chilli

    Going to use the ‘torch on as I’ve got it anyway and it’s better quality than the felts I’ve seen (based only on what I’ve seen though )

    It’s just a small area, timber trims on three sides at overhangs and timber upstand to house wall, these will be fixed with tacks : screws

    Roof deck, (osb) could either loose lay as with regular felt or, again as I’ve got a tin, Black Jack Felt Adhesive

    Get the point about tacks going through a waterproof roof covering - seems counter-intuitive when you think about it !

    Got 2 small sheds in my own garden both with felt roofs, when I recovered these, put a blob of roofing mastic at every tack point on overlaps and banged in tacks through the gunge

    Thought process is that mastic will form a seal at entry point and under tack head ?

    Who knows ? All dry inside and made me feel better so that’s the main thing innit :)
  9. Tilt

    Tilt Active Member

    No... Printing factory in Basford, Notts. :)

    @DIYDave. Trust me bud, the hairspray idea will work a treat...
    Lay it on the OSB and roll (or fold / without creasing, obvs) half of it back.
    Alight the spray and immediately apply heat (side to side as like spray painting) to the felt and as it starts to soften (you will see the colour subtly change) just roll it over back onto the OSB as you go.
    Pull slightly back as you go to check it is sticking and apply a little more heat if not.

    Probably do each half in one go if you wear heat proof gloves.
    Last edited: Aug 27, 2021
  10. DIYDave.

    DIYDave. Screwfix Select

    Thanks again for the tips

    Will consider the hairspray idea although a little wary of aerosols and flames as nearly lost an eye as a kid when one in a bonfire exploded and launched itself at my face (yeah I was probably way too close but had no idea there was a pressurised ‘bomb’ in the embers)

    Will play around at the weekend with a scrap of osb and felt and try the hot air gun and also the Black Jack adhesive

    Usual felt shed is just loose laid anyway so don’t even know if it’s worth bonding this small sheet - depth is only around 450mm and all 4 edges will have timber trims attached over felt

    I’ve got a plumbing torch but it runs on Mapp Gas - way too hot for the felt, can imagine it will destroy it in seconds :(

    Will have a play around and report back - thanks to all the above and have a great BH Weekend one and all

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