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Posted to uk.d-i-y
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Hot tin roof?
In message , T i m
writes
Hi All,
I asked a while back about considerations when raising the pitch on a
garage / workshop roof (to make more of a 'loft' / storage space) and
I'm now, after seeing some in use, considering that pre coloured galv
steel roofing you often see in the bigger profiles cladding the walls
and roofs of the sheds we all know and love. ;-)
I'm told it would be much noisier than the existing corrugated cement
fibre (and I would have to replace that anyway as it would be too
short with a higher pitch) but I see you can get self insulated
panels but not sure if they meet the requirements of 'non combustible'
(I'm thinking of the insulation rather than the panels here).
I've even seen (but now can't find) a simulated slate (I've found the
tile one) that would be in keeping with our and many of the houses
round here.
The pro's for me could be that it might be lighter than cement fibre
(easier for me to do), possibly more secure (you couldn't just break
it open) and could be pre-insulated?
So, has anyone here used such stuff themselves and can point out any
pitfalls etc please?
try
I used their 80mm AS35 foam sandwich for a large, pitched roof workshop
without any real problems.
Points to consider are....
the sheets arrive cut to length: one end square and the other
having a 50mm rain drip (insulation and under sheet cut back). When you
fix this as a lean-too or ridge there is a triangle of uninsulated
space which needs filling with fire rated expanding foam.
flashing is made to your specification but sits on top of the
roofing ribs. Metre wide foam gap fillers are available but need to be
trapped by the flashing fixing screws.
Fixing screws are available for metal or wooden purlins.
rolls of mastic tape are required to prevent heavy rain bouncing under
the lap joins. This is applied to the underside of the lap but requires
care when lifting the sheet into position. Pair of hands needed at top
and bottom. Lap stitching screws are essential.
The biggest problem I encountered was how to attach the guttering and
how to seal off the exposed foam. Steadmans did not offer any solutions.
In the end I got some 100mm x 75mm pine cut diagonally (done by my
timber supplier with a band saw) which suited my roof pitch. Fixing was
by some home made *Z* shaped galvanised steel strips and the wood dosed
with preservative.
Things you may not realise about ribbed roofing..... not all buildings
are built square, my barn is 1m longer on one side than the other. This
is not a problem where the gutter is longer than the ridge however, on
the other side, the ribs conduct rain water over the end of the
building. Luckily I had some left over extruded aluminium gutter from a
greenhouse which was fitted behind the flashing.
regards
--
Tim Lamb
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