Hi,
I have a garage with an old corrugated asbestos roof. The roof has a number
of small holes where the rain gets in. Also, a draught gets in through gaps
where the sheets overlap. Would expanding foam be suitable to plug these
gaps and holes?

Cheers,

Al

Al 1953 :
I have a garage with an old corrugated asbestos roof. The roof has a number
of small holes where the rain gets in. Also, a draught gets in through gaps
where the sheets overlap. Would expanding foam be suitable to plug these
gaps and holes?

I don't know but faced with the same problem I used clear silicone
sealant to good effect. It kept the rain out and it was inconspicuous.

--
Mike Barnes

Al 1953
wibbled on Saturday 27 March 2010 12:18

Hi,
I have a garage with an old corrugated asbestos roof. The roof has a
number of small holes where the rain gets in. Also, a draught gets in
through gaps where the sheets overlap. Would expanding foam be suitable to
plug these gaps and holes?


Yes, foam should work very well on the overlaps. For the holes, the foam
willbe too exposed to the sun, which rots it. Silicon some patches of rubber
or plastic or ali sheet over these could be one simple answer.

--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.

Al 1953 wrote:
Hi,
I have a garage with an old corrugated asbestos roof. The roof has a number
of small holes where the rain gets in. Also, a draught gets in through gaps
where the sheets overlap. Would expanding foam be suitable to plug these
gaps and holes?


could be. Or use any frame sealer designed for exterior us, or even a
mastic or putty.

Its only a hole, innit?

Cheers,

Al

Al 1953 wrote:

I have a garage with an old corrugated asbestos roof. The roof has a
number of small holes where the rain gets in. Also, a draught gets in
through gaps where the sheets overlap. Would expanding foam be suitable to
plug these gaps and holes?


Dunno about expanding foam, I've avoided it since I made a mess all over the
window frames.

I'd have a first try with the acrylic roof repair with fibres in it, that
wickes sell, this deals with small gaps.

Next I'd look at hot melt on hi performance roofing felt. I've used this on
an asbestos fibre garage roof where yobbos had through a brick through it,
still good after 10+ years.

AJH

On 27 Mar, 12:18, Al 1953 wrote:
I have a garage with an old corrugated asbestos roof.

Read a couple of recent threads on asbestos and its hazards,
particularly for roofing.

The roof has a number of small holes where the rain gets in. Also, a draught gets in through gaps
where the sheets overlap. Would expanding foam be suitable to plug these
gaps and holes?

Squirty foam is great on the gaps in overlaps. However it has little
strength and very poor UV resistance, so it's not good for holes. If
you do use it for holes, you'll certainly need to cover the outside
with something opaque, such as aluminum tape. or even thick aluminium
foil (caterer's buffet trays, in my shed).

A better repair though might be more asbestos, such as offcuts of
other sheets.

A really useful tube mastic here is the black very slow drying
bituminous one from Wickes or Screwfix, sold as roof repair mastic.
It's sticky, flexible, and it just doesn't care about water. You can
seal wet boards, even while it's still raining.

Al 1953 pretended :
I have a garage with an old corrugated asbestos roof. The roof has a number
of small holes where the rain gets in. Also, a draught gets in through gaps
where the sheets overlap. Would expanding foam be suitable to plug these
gaps and holes?

Ordinary mortar works well on the larger holes, if the panel is cleaned
up a little first. Silicon frame sealant works well to stop both blown
rain and drafts, if forced into the overlap from the inside. Sometimes
it can help if the gap is prised apart gently to increase it, before
pushing the sealant in.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

The message
from Al 1953 contains these words:

Hi,
I have a garage with an old corrugated asbestos roof. The roof has a number
of small holes where the rain gets in. Also, a draught gets in through gaps
where the sheets overlap. Would expanding foam be suitable to plug these
gaps and holes?

Expanding foam fine for along the edges of sheets if used from the inside.

For small holes, cracks etc. Any sort ofd scrim with several layers of
thick bituminous paint. Stick it into the first layer and then paint
over several times.

On Mar 27, 12:18*pm, Al 1953 wrote:
Hi,
I have a garage with an old corrugated asbestos roof. The roof has a number
of small holes where the rain gets in. Also, a draught gets in through gaps
where the sheets overlap. Would expanding foam be suitable to plug these
gaps and holes?

Cheers,

Al

Which laps are the gaps in, bottom or side ?. Stitch bolts and plastic
washers are used to fill old fixing holes.

Kipper at sea wrote in
:

On Mar 27, 12:18*pm, Al 1953 wrote:
Hi,
I have a garage with an old corrugated asbestos roof. The roof has a
numb
er
of small holes where the rain gets in. Also, a draught gets in
through ga
ps
where the sheets overlap. Would expanding foam be suitable to plug
these gaps and holes?

Cheers,

Al

Which laps are the gaps in, bottom or side ?. Stitch bolts and plastic
washers are used to fill old fixing holes.

Thanks for the great suggestions, everyone. the gaps are at the overlaps,
at the ends/bottoms of each sheet. I had to repair the roof using some
corrugated asbestos that was slightly different "wavelength" to the
original stuff... or maybe the original stuff had got flattened a bit over
the years. So I have bigger gaps than I would have if the whole job had
been done with identical sheets. Owing to a scarcity of spare sheets to
affect the repair, I have ended up with only 4" overlaps down one strip of
the roof. So the expanding foam will be particularly necessary, for
stopping the wind blowing rain back in, under the overlaps.

Al