Help! Wall insulation
 

I have been lumbered with a porch on our ground floor flat with two
external masonry walls (one course of bricks).

To make the room habitable I need to install floor, wall, and probably
roof insulation (flat, cold roof).

So far I have applied a bitumenous damp proofing to the concrete slab,
and lined these walls with a treated timber frame 100mm thickness (with
a gap between it an the external walls varying from 10mm to 100mm due
to the curved wall).

My question is- how can I best insulate these external walls? I was
thinking masonry DPM timber frame with insulation inserted in
between timbers. Will this be adequate for warmth and the building
inspector?

Rockwool cavity seems to be a good balance between quality and value
although I'm not sure it is suitable for insertion between the timbers
like I plan.

Please provide some guidance.

Many thanks

Daniel

Help! Wall insulation
 

Danny,
I posted this just recently...............
Just thought I'd share this info with everyone. I've just added
a Dormer to a new upstairs room. Basically 4" x 2" (95mm x 45mm) stud

walls. I've 'stuffed' it with the following insulation called Rocksilk

by Knauf. The spec. sheet gives the following details...


UNIVERSAL SLAB RS45
Thickness 100mm (I have also used 75mm)

Length: 1200mm
Width: 600mm
Area per pack (m^2): 3.6
Lamda (W/mK): 0.035
R Value (m^2K/W): 2.85
Fire ClassSlabs per Pack: A1
Pack per Pallet: 5
Product Code: 2361392


The price for one pack from Sheffield Insulations in Aberdeen
was £32. So that's nearly £10 per square metre. Quite expensive for
what it is.
It is good to work with, easily cut with a breadknife. Just
cut it about a quarter inch oversize and push between the studs.


Chris.

Help! Wall insulation
 

Cheers for that.

Did you put the DPM behind the insulation, or in front (before the
plasterboard)?

Thanks

Help! Wall insulation
 

On 24 Nov 2005 09:44:51 -0800, a particular chimpanzee named "daniel"
randomly hit the keyboard and produced:

I have been lumbered with a porch on our ground floor flat with two
external masonry walls (one course of bricks).

My question is- how can I best insulate these external walls? I was
thinking masonry DPM timber frame with insulation inserted in
between timbers. Will this be adequate for warmth and the building
inspector?

Hmm. The last question will depend on whether you're converting a
porch into a habitable part of the dwelling or whether it was part
before. If the latter, then you're not making the situation worse
than previously and therefore don't need a Building Regulations
application. If the former and you are 'renovating' the walls, roof
or floor over a substantial area, you should insulate to a
'reasonable' standard.

To answer your first question; you would be better with a PIR
insulation such as Celotex, Kingspan, Xtratherm, etc. between the
studs, and a vapour barrier on the _inside_ (polythene or foil backed
plasterboard) to prevent condensation from within the building getting
into the timbers.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"

Help! Wall insulation
 

daniel wrote:
Cheers for that.

Did you put the DPM behind the insulation, or in front (before the
plasterboard)?

Thanks

No I didn't as this is effectively an extension of the
roof itself so there is roofing felt, then 22mm. sarking boards, then
95mm. studs packed with that RockSilk insulation, then 12.5mm
plasterboard. There seems to be two schools of thought regarding
putting polythene on top of the insulation and under the plasterboard.
Who wants to live in a poly-bag?

Chris.

Help! Wall insulation
 

On 25 Nov 2005 03:16:21 -0800, wrote:

daniel wrote:
Cheers for that.

Did you put the DPM behind the insulation, or in front (before the
plasterboard)?

Thanks

No I didn't as this is effectively an extension of the
roof itself so there is roofing felt, then 22mm. sarking boards, then
95mm. studs packed with that RockSilk insulation, then 12.5mm
plasterboard. There seems to be two schools of thought regarding
putting polythene on top of the insulation and under the plasterboard.
Who wants to live in a poly-bag?

Chris.

You will get condensation on the sarkin boards. Can you get access
from the attic to inspect?

Help! Wall insulation
 

The porch was not part of the dwelling before as there was an exterior
grade door between it and the dwelling, so my understanding is that we
will have to insulate to a reasonable standard.

Thanks for the advice, I think I'll pack the studs and then use a lined
plasterboard as you mentioned.

Help! Wall insulation
 

Ok, seems to be a similar situation to me then.