On 25/06/2018 10:54, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
On 24/06/2018 16:33, DerbyBorn wrote:
After about 30 years the shed roof needs re-felting - one side has slipped
due to the wind and sun.

Originally it was nailed with galvanised nails. Where it was nailed it has
now torn.

Is there a better way using glue nowadays?

There are several options... the traditional three layer felt would use
a nail prep layer (a hessian re-enforced felt) random nailed, and then
underlay and top felt layers hot bonded with tar or glued to that.

My personal preference is using torch on felt (usually a modified /
rubberised bitumen style like SBS felt). Just two layers - a 2mm
underlay, and then a 4mm mineral finish top coat. Sticks like the
proverbial to a blanket, and very quick and easy to apply so long as you
have or can borrow a decent sized blow torch.

Would you expect that to last 30 years? Mine was made like that and has
needed a few repairs - apparently were the adhesion had failed.

I have not had any indication of loss of adhesion with the torch on
stuff I have used so far. So I would expect it to last toward the upper
end of what you can expect from felt in general. However none of the
jobs I have done with it are 30 years old yet, so I can't say for
certain from personal experience.

If looking for maximum life, then two layers of undercoat would probably
help.



--
Cheers,

John.

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