I suspect rain is blowing under the rather narrow steel ridge capping
fitted to one of my barns.

Second hand box section rolled steel sheeting was laid on top of an
existing but leaky felted roof. I am now finding that water is making
its a way under the steel roofing and through the felt.

There are several possibilities... the sheets are secured with heavy
duty roofing nails with a trapped plastic seal. The laps are screwed at
18" intervals but there is no mastic seal. The ridge cap is narrow so
rainwater could splash and blow under.

I have in mind to fabricate a template/former in 12mm ply to fit tightly
to the roof sheet, pierced with holes to allow conventional canned
expanding foam to be fed into the ridge and form a tidy seal. Freehand
attempts leave an unsightly bulge and reveals large gas pockets when
trimmed.

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Any other constructive thoughts?

regards
--
Tim Lamb

Tim Lamb wrote:

I suspect rain is blowing under the rather narrow steel ridge capping
fitted to one of my barns.

Second hand box section rolled steel sheeting was laid on top of an
existing but leaky felted roof. I am now finding that water is making
its a way under the steel roofing and through the felt.

There are several possibilities... the sheets are secured with heavy
duty roofing nails with a trapped plastic seal. The laps are screwed at
18" intervals but there is no mastic seal. The ridge cap is narrow so
rainwater could splash and blow under.

I have in mind to fabricate a template/former in 12mm ply to fit tightly
to the roof sheet, pierced with holes to allow conventional canned
expanding foam to be fed into the ridge and form a tidy seal. Freehand
attempts leave an unsightly bulge and reveals large gas pockets when
trimmed.

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Any other constructive thoughts?

regards

Mineral oil perhaps? eg baby oil.

IME takes a minute for primary expansion, but it goes on oozing slowly for
10-20 minutes. Temperature might have an effect - the above was 20C.

HTH

--
Tim Watts

Tim Lamb wrote:
I suspect rain is blowing under the rather narrow steel ridge capping
fitted to one of my barns.

Second hand box section rolled steel sheeting was laid on top of an
existing but leaky felted roof. I am now finding that water is making
its a way under the steel roofing and through the felt.

There are several possibilities... the sheets are secured with heavy
duty roofing nails with a trapped plastic seal. The laps are screwed at
18" intervals but there is no mastic seal. The ridge cap is narrow so
rainwater could splash and blow under.

I have in mind to fabricate a template/former in 12mm ply to fit tightly
to the roof sheet, pierced with holes to allow conventional canned
expanding foam to be fed into the ridge and form a tidy seal. Freehand
attempts leave an unsightly bulge and reveals large gas pockets when
trimmed.

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Any other constructive thoughts?

regards
Varnish the ply and then spread a film of cheap grease on it including
the holes.
Unhelpfully, you possible need to leave it for a few hours.
Maybe misting with some water might help to accelerate the cure?
Try experimenting.

Bob

On Nov 25, 10:05*pm, Tim Lamb wrote:
I suspect rain is blowing under the rather narrow steel ridge capping
fitted to one of my barns.

Second hand box section rolled steel sheeting was laid on top of an
existing but leaky felted roof. I am now finding that water is making
its a way under the steel roofing and through the felt.

There are several possibilities... the sheets are secured with heavy
duty roofing nails with a trapped plastic seal. The laps are screwed at
18" intervals but there is no mastic seal. The ridge cap is narrow so
rainwater could splash and blow under.

I have in mind to fabricate a template/former in 12mm ply to fit tightly
to the roof sheet, pierced with holes to allow conventional canned
expanding foam to be fed into the ridge and form a tidy seal. Freehand
attempts leave an unsightly bulge and reveals large gas pockets when
trimmed.

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Any other constructive thoughts?

regards

oil of any sort, diesel.
Leave overnight to expand fully.


NT

On Nov 25, 10:05*pm, Tim Lamb wrote:
I suspect rain is blowing under the rather narrow steel ridge capping
fitted to one of my barns.

Second hand box section rolled steel sheeting was laid on top of an
existing but leaky felted roof. I am now finding that water is making
its a way under the steel roofing and through the felt.

There are several possibilities... the sheets are secured with heavy
duty roofing nails with a trapped plastic seal. The laps are screwed at
18" intervals but there is no mastic seal. The ridge cap is narrow so
rainwater could splash and blow under.

I have in mind to fabricate a template/former in 12mm ply to fit tightly
to the roof sheet, pierced with holes to allow conventional canned
expanding foam to be fed into the ridge and form a tidy seal. Freehand
attempts leave an unsightly bulge and reveals large gas pockets when
trimmed.

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Any other constructive thoughts?

regards
--
Tim Lamb


Clingfilm stops it sticking. Raid the wife's kitchen:-)

When you start using a can, the foam expands a lot more than the final
bit that comes out. Also in cold weather it expands a lot less and
takes longer to go off. So, can't say, A skin forms on the outside
first usually in about twenty minutes at room temps. The thicker it
is the longer it takes. You can spray water at it to accelarate it
but that affects appearance.
It needs moisture to make it go off. But it still sticks to wet
things.

On Nov 25, 10:05*pm, Tim Lamb wrote:
I suspect rain is blowing under the rather narrow steel ridge capping
fitted to one of my barns.

Second hand box section rolled steel sheeting was laid on top of an
existing but leaky felted roof. I am now finding that water is making
its a way under the steel roofing and through the felt.

There are several possibilities... the sheets are secured with heavy
duty roofing nails with a trapped plastic seal. The laps are screwed at
18" intervals but there is no mastic seal. The ridge cap is narrow so
rainwater could splash and blow under.

I have in mind to fabricate a template/former in 12mm ply to fit tightly
to the roof sheet, pierced with holes to allow conventional canned
expanding foam to be fed into the ridge and form a tidy seal. Freehand
attempts leave an unsightly bulge and reveals large gas pockets when
trimmed.

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Any other constructive thoughts?

regards
--
Tim Lamb

Or WD40.

In message
, NT
writes
On Nov 25, 10:05*pm, Tim Lamb wrote:
I suspect rain is blowing under the rather narrow steel ridge capping
fitted to one of my barns.

Second hand box section rolled steel sheeting was laid on top of an
existing but leaky felted roof. I am now finding that water is making
its a way under the steel roofing and through the felt.

There are several possibilities... the sheets are secured with heavy
duty roofing nails with a trapped plastic seal. The laps are screwed at
18" intervals but there is no mastic seal. The ridge cap is narrow so
rainwater could splash and blow under.

I have in mind to fabricate a template/former in 12mm ply to fit tightly
to the roof sheet, pierced with holes to allow conventional canned
expanding foam to be fed into the ridge and form a tidy seal. Freehand
attempts leave an unsightly bulge and reveals large gas pockets when
trimmed.

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Any other constructive thoughts?

regards

oil of any sort, diesel.
Leave overnight to expand fully.

Hmmm...

I think this is heading back to the *trim off the excess* route.

Using cans rather than a professional gun, I need to empty the can
before the foam sets in the nozzle. Now that the suppliers have learned
to keep the nozzles under the counter, having a fresh one to screw on is
not practical.

There is about 40' of roof to do!

I suppose I could purchase some commercial foam ridge seals. They are
normally only 1 ukp each and comparable to tinned foam.

Thanks to all.

regards


NT

--
Tim Lamb

Tim Lamb wrote:
In message
, NT
writes
On Nov 25, 10:05 pm, Tim Lamb wrote:
I suspect rain is blowing under the rather narrow steel ridge capping
fitted to one of my barns.

Second hand box section rolled steel sheeting was laid on top of an
existing but leaky felted roof. I am now finding that water is making
its a way under the steel roofing and through the felt.

There are several possibilities... the sheets are secured with heavy
duty roofing nails with a trapped plastic seal. The laps are screwed at
18" intervals but there is no mastic seal. The ridge cap is narrow so
rainwater could splash and blow under.

I have in mind to fabricate a template/former in 12mm ply to fit tightly
to the roof sheet, pierced with holes to allow conventional canned
expanding foam to be fed into the ridge and form a tidy seal. Freehand
attempts leave an unsightly bulge and reveals large gas pockets when
trimmed.

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Any other constructive thoughts?

regards

oil of any sort, diesel.
Leave overnight to expand fully.

Hmmm...

I think this is heading back to the *trim off the excess* route.

Using cans rather than a professional gun, I need to empty the can
before the foam sets in the nozzle. Now that the suppliers have learned
to keep the nozzles under the counter, having a fresh one to screw on is
not practical.

There is about 40' of roof to do!

I suppose I could purchase some commercial foam ridge seals. They are
normally only 1 ukp each and comparable to tinned foam.

Thanks to all.


Normally its squidge and trim.

The foam cuts well with a fine bladed saw - tenon or crosscut.

Or simply put a decorative fascia there to form most of the boundary and
use little enough so it doesn't squidge at all.

regards


NT

pinkgrip drywall fixing foam only expands to double, not ten times,
i used it to temporarily fix ridges
(for a few years?)
and for loads of draughtproofing jobs

On 25/11/11 22:05, Tim Lamb wrote:
I suspect rain is blowing under the rather narrow steel ridge capping
fitted to one of my barns.

Second hand box section rolled steel sheeting was laid on top of an
existing but leaky felted roof. I am now finding that water is making
its a way under the steel roofing and through the felt.

There are several possibilities... the sheets are secured with heavy
duty roofing nails with a trapped plastic seal. The laps are screwed at
18" intervals but there is no mastic seal. The ridge cap is narrow so
rainwater could splash and blow under.

I have in mind to fabricate a template/former in 12mm ply to fit tightly
to the roof sheet, pierced with holes to allow conventional canned
expanding foam to be fed into the ridge and form a tidy seal. Freehand
attempts leave an unsightly bulge and reveals large gas pockets when
trimmed.

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Any other constructive thoughts?

regards

On Fri, 25 Nov 2011 22:05:01 +0000, Tim Lamb
wrote:

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Polyethylene film. Bin liner, whatever. Peels off the foam a treat.


Thomas Prufer

In message , Thomas Prufer
writes
On Fri, 25 Nov 2011 22:05:01 +0000, Tim Lamb
wrote:

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Polyethylene film. Bin liner, whatever. Peels off the foam a treat.

Yes.

Cling film was suggested as well.

On realising how long the cure/full expansion time is I decided to fall
back to the *trim off the surplus* method.

regards

--
Tim Lamb

"Tim Lamb" wrote in message
...

In message , Thomas Prufer
writes
On Fri, 25 Nov 2011 22:05:01 +0000, Tim Lamb
wrote:

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Polyethylene film. Bin liner, whatever. Peels off the foam a treat.

Yes.

Cling film was suggested as well.

On realising how long the cure/full expansion time is I decided to fall
back to the *trim off the surplus* method.

regards


Tim, for trimming when hardened, a 12" hacksaw blade with a handle made from
gaffa tape wrapped round one end works well.

AWEM

In message , Andrew Mawson
writes
"Tim Lamb" wrote in message
.. .

In message , Thomas Prufer
writes
On Fri, 25 Nov 2011 22:05:01 +0000, Tim Lamb
wrote:

How do I stop the foam sticking to the plywood? And, how long does it
take before full expansion is reached?

Polyethylene film. Bin liner, whatever. Peels off the foam a treat.

Yes.

Cling film was suggested as well.

On realising how long the cure/full expansion time is I decided to
fall back to the *trim off the surplus* method.

regards


Tim, for trimming when hardened, a 12" hacksaw blade with a handle made
from gaffa tape wrapped round one end works well.

There is already one in the rule pocket of my overalls:-)

regards
--
Tim Lamb

On Sat, 3 Dec 2011 10:20:20 -0000, Andrew Mawson wrote:

Tim, for trimming when hardened, a 12" hacksaw blade with a handle made
from gaffa tape wrapped round one end works well.

You don't have a proper pad saw handle?

http://mysite.verizon.net/timetrvlr/eclip2.JPE

--
Cheers
Dave.

In message o.uk, Dave
Liquorice writes
On Sat, 3 Dec 2011 10:20:20 -0000, Andrew Mawson wrote:

Tim, for trimming when hardened, a 12" hacksaw blade with a handle made
from gaffa tape wrapped round one end works well.

You don't have a proper pad saw handle?

http://mysite.verizon.net/timetrvlr/eclip2.JPE

I do but only for a 12" blade. My rule pocket knife (and I guess
Andrew's) is made from the much stronger power hacksaw blades:-)

regards


--
Tim Lamb

On Mon, 5 Dec 2011 17:48:32 +0000, Tim Lamb
wrote:

My rule pocket knife (and I guess
Andrew's) is made from the much stronger power hacksaw blades:-)

Those are excellent jobber's knives.