Our single story living room extension is in serious need of a roof void
insulation upgrade. There's no access from below so I plan to take some
tiles off and roll out some glass wool.

Is there a 'preferred' felt with which I should 'repair' the roof after
I've finished?

--
F

F wrote:
Our single story living room extension is in serious need of a roof void
insulation upgrade. There's no access from below so I plan to take some
tiles off and roll out some glass wool.

Please use celotex/kingspan.


Is there a 'preferred' felt with which I should 'repair' the roof after
I've finished?

Dunno. Tyvex?

On Mar 3, 7:38 pm, The Natural Philosopher
wrote:
F wrote:
Our single story living room extension is in serious need of a roof void
insulation upgrade. There's no access from below so I plan to take some
tiles off and roll out some glass wool.

Please use celotex/kingspan.

Not necessarily no - as we know *nothing* about the construction or
size/shape..

In any case in such a "no access to" space a good thickness of
"special offer" glass wool will probably be a damn sight easier to
obtain, transport and fit successfully than any board/sheet
material....it may even be cheaper too but ICBA to find the
comparitive figures....

Is there a 'preferred' felt with which I should 'repair' the roof after
I've finished?

anything modern (i.e. plastic) will outlast anything
"traditional" (e.g. sarking felt) - I'd generously overlap the old
gear to minimise leak risks....

Jim K

On 03/03/2011 20:27 Jim K wrote:

In any case in such a "no access to" space a good thickness of
"special offer" glass wool will probably be a damn sight easier to
obtain, transport and fit successfully than any board/sheet
material....it may even be cheaper too but ICBA to find the
comparitive figures....

25 sq metres of 200mm cost me £15: recent B&Q offer.

Is there a 'preferred' felt with which I should 'repair' the roof after
I've finished?

anything modern (i.e. plastic) will outlast anything
"traditional" (e.g. sarking felt) - I'd generously overlap the old
gear to minimise leak risks....

I'll look for something plasticky then! And take the advice on a
generous overlap: there'll be plenty as I won't be cutting a roll sized
hole!

--
F

On Thu, 03 Mar 2011 21:04:18 +0000, F wrote:

I'll look for something plasticky then!

Tyvek is onee of the makers of modern "plastic" breathable sarking.

And take the advice on a generous overlap:

Wider than the hole, under the old sarking at the top. A cut in the
old at the top of the sides to let the new out from under the old
over the sides, old side edges higher than the old sarking if
possible, new over the old full width of the patch along the bottom.
I have a feeling that is as clear as mud...

Might be wort playing with bits of paper to work out what needs to be
done to make a reasonably water tight patch.

--
Cheers
Dave.

On Mar 3, 9:04 pm, F news@nowhere wrote:
On 03/03/2011 20:27 Jim K wrote:

In any case in such a "no access to" space a good thickness of
"special offer" glass wool will probably be a damn sight easier to
obtain, transport and fit successfully than any board/sheet
material....it may even be cheaper too but ICBA to find the
comparitive figures....

25 sq metres of 200mm cost me 15: recent B&Q offer.

Is there a 'preferred' felt with which I should 'repair' the roof after
I've finished?

anything modern (i.e. plastic) will outlast anything
"traditional" (e.g. sarking felt) - I'd generously overlap the old
gear to minimise leak risks....

I'll look for something plasticky then! And take the advice on a
generous overlap: there'll be plenty as I won't be cutting a roll sized
hole!

more effective to just look for modern roofing felt ;)

(& IMHO Dave L's patching advice is sound)

Jim K

On 03/03/11 19:38, The Natural Philosopher wrote:
F wrote:
Our single story living room extension is in serious need of a roof
void insulation upgrade. There's no access from below so I plan to
take some tiles off and roll out some glass wool.

Please use celotex/kingspan.



at the thin lower edge where the roof meets the wall
I used kingspan and foam
so there wasnt a gap in the insulation.

[g]