Have been looking at this overnight, you say the cabling could go in the gap created between insulation and plasterboard.. currently the electric cabling is attached to the brick wall with galvonised trunking/channeling running down from ceiling to socket as specified by my electrician, if the insulation goes direct to the wall will the ring main wiring and the cooker spur not need fixing and protecting in some way?

Also the brick wall isnt exactly level, it was built in 1943 so by modern standards it looks like someone built it whilst drunk, the bricks are not flush in all cases too - one advantage with dab and dot that was pointed out to me by many people was that both these imperfections could be taken out / worked around.

The British Gypsum website doesnt show an option of dab and dot for installation on solid external walls - to be compliant should there be an air gap between the brick wall and the insulation? if not, 12.5mm adhesive, 70mm insulation and 12.5mm plasterboard is possibly my thinner option, but still leaves the issue of nailing kitchen cupboards to it..

what
happens to the cables in a stud wall?
what does the cable cap protect the cable from? certainly isnt drilling or nailing...
you can take imperfections out of a wobbly wall loads of ways, offer some dab up to the wall before you offer the boards up, give it a dubbing out coat of sand and cement (better than dabbing anyway) use framing screws with 2 threads, one for the masonary, one for the timber, you can wind em in and out till its where you want it or just pack the battens with thin bits of ply...

_________________
http://www.peterborough-plasterer.co.uk/

me again :D

xtratherm, looking at doing this as have a local supplier. filled between battons with backed board over the top. website asks what u value i'm working to, this is 0.30 ?

site states batton with 40mm between and 30mm insulated board gives 0.31 - is this close enough?

if my calculations are right, this is 40mm+30mm+12.5mm flush to wall.

would it be good practice to line the wall with some form of vapour barrier before battoning?

Cheers
Chris

which xtratherm product are you looking at?

most of the xtratherm products have built in vapour barriers i believe

thin r

That looks to combine vapour barrier, however if the battens are to the wall does that provide continuous vapour barrier?

ARGH this is a mine field!!

http://www.xtratherm.com/wallsolutions/ ... od%201.pdf

I've looked over the entire website, i can see it says 40mm for the board to go between the battons, but i cannot find anywhere how thick the thermal liner (insulated plasterboard) should be to meet the 0.30 u value..

can anyone assist, decipher or used this recently?

as always thanks in advance..

http://www.xtratherm.com/wallsolutions/ ... alfix4.php

have a look at this one, the table at the bottom gives the achieved u value for the type of wall you have per thickness required...
so 50mm will achieve 0.31 on a solid 9" (225mm) wall..
plus 25mm batten plus 12.5mm plasterboard plus 2.5mmm skim
80/90 mil


http://www.xtratherm.com/wallsolutions/ ... alfix1.php

this one uses 40mm battens to wall, then 40mm insulated board to give you 0.28 on a 9" wall or 30mm insulated board to get 0.32...
so 70 or 80mm plus the 12mm plasterboard...

either / or method to be honest, the table changes as the method changes, very useful tool..

theres another 3 methods on there, the tables give all the figures at the bottom

http://www.xtratherm.com/wallsolutions/ ... alfix5.php
http://www.xtratherm.com/wallsolutions/ ... alfix3.php
http://www.xtratherm.com/wallsolutions/ ... alfix3.php

_________________
http://www.peterborough-plasterer.co.uk/

thing is, if you try to put the boards straight on the wall over the cables, you tend to find they bulge a bit where the cables are...
if your walls all over the place and its not something you can knock off youre probably better of using no.2 and lose the snots and cables in between the battens and using 60mm insulated boards and 90mm drywall screws on 25mm treated battens or metal liner

another thing you can do is use 50mm battens for a 40mm infill panel, that'll give you 10mm of play behind the insulation to stop it bulging out, then another 30 or 40mm insulated board over the top to get 0.28 or 0.32 - 75mm or 85mm drywall screws
so 80 or 90mm plus board...

separate vapour barrier not required using insulated boards, but if you just use say, 80mm batten, 70mm insulation between then standard board over the top, you need to polythene the framework and insulation off before you board it or use duplex foil backed plasterboards...
the old spec sometimes used to be vapour barrier and duplex boards

or dot and dab
http://www.xtratherm.com/wallsolutions/ ... vefix6.php
60mm insulation to get 0.31, plus 15mm plasterboard and skim, dabthickness say 15mm,
90mil..
tricky fixing stuff to it though all the weight is on the boards... plasterboard fixings or battens on concrete screws and fix to the battens

_________________
http://www.peterborough-plasterer.co.uk/

Cheers, went with 40mm within batton plus 40mm backed over. i've used 44mm battons to give me a small amount of space to play with - not the most i know but i've only got 2.4 meters to start with!! :)

thanks again for your advise

I went the insulation between battons and insulated plasterboard over the top

The plasterboard makes the vapour barrier, does this need taping up to provide a complete barrier? If so what should I use?

I bought some plasterboard 'tape' but it appears to be a mesh type material

Cheers
Chris

be fine like that mate..

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http://www.peterborough-plasterer.co.uk/

Last question i hope...

working on that two boards meet at a 90 degree angle at corners or reveals etc, either running the reveal board or the main board long ends in insulation being exposed - what is the correct way to deal with this?

do i chase out a bit of insulation off one of them to have a plasterboard to plasterboard join, or do i put a bit of plasterboard over to cover the insulation or can i tape over it?

Cheers
Chris

yeh just rip some of the insulation off one of the boards so the plasterboard meets correctly, then just stick a bead on the corner...

_________________
http://www.peterborough-plasterer.co.uk/

Me again :D

I've got to get about 1.5 boards of (heavy) 2" backed plasterboard up to the roof which at it's highest is about 3 meters, not going to be easy

Any obvious issues with doing it in say four or 5 smaller strips?


Building control visited yesterday to view 'pre plaster' - apart from him immediately noticing we'd removed a wall, he passed it so far and we're ok to carry on. I've no doubt that he raised no issues due to seeing I've gone above and beyond requirements - so thanks for all your help and support with this.