Is dry lining needed?

Of course.

Unless BCO says it needs more insulation.

In article , DerbyBorn writes

Could get bldy cold, long and narrow means a lot of wall for not a lot of area so proportionately heat loss is greater. Could mean a cold kitchen or condensation in or behind the units.

What is the wall construction, solid or cavity, how thick (for solid) and insulated cavity or not?

If it's a cavity I'd be happy to try your skim idea with one coat plaster (no bonding) but if it's solid I'd be inclined to bond some thin celotex directly to it and then bond a layer of PB to that. Exact method depending on degree of exposure of outside to driving rain.

Watch out for nasty rules that force you to meet new build insulation requirements if you 'modify a thermal element' of a building's construction eg. take down a ceiling or (I think) strip all the plaster off a wall.

On Friday 01 March 2013 15:04 fred wrote in uk.d-i-y:

As I read it, the OP is not creating extra external wall area, he's just moving a wall sideways - am I right? In which case it won't be much worse, unless the new wall has worse thermal properties than the current one.

Ideally (and legally) as you say, the new wall should be an insulated - if space is tight, this could be done without a full brock cavity. I'm thinking a single skin wall, external insultation and cladding.

Plaster isnt essential, plenty of outbuildings do without it. Too little info to discuss insulation.

NT

I wouldn't entertain the idea - you are talking about a few millimetres, and walls can't be skimmed without a backing coat, usually about half an inch (12.5mm), you can get 9mm plasterboard dry lining and leave the skimming off if it's to be tiled

a couple of mil of bonding and then skim..

In a kitchen with external walls - I'd take the opportunity to use some insulation. It'll either haemorrhage heat or drip with condensation when cooking/cleaning.

Rob

RJH wrote in news:KeKdnZacNIoKtq snipped-for-privacy@bt.com:

The issue is that a wall that is to be extended will change from single block where it is currently an internal wall - to becoming a double skin beyond the existing end of the house. This will give me a step in the wall in the kitchen that I want to minimise whilst complying with cavity wall building regs. The BCO is allowing the cavity to be the same as the cavity i the rest of the house (1988 build).

OK so 5mm of bonding and 2mm of skimming, or:

like I said, we are talking about saving 5mm of space - not worth a carrot

The difference will be less than an inch, probably less than half an inch, not worth bothering about

Tell the builders that the finished line of the new wall is to be flush with the fisnished line of the current wall. Ie they build the new wall in the right place so this happens...

"Dave Liquorice" wrote in news: snipped-for-privacy@srv1.howhill.co.uk:

Can't - a single wall is going to become a cavity wall in the extended part.

No such thing as "can't", difficult and/or expensive yes but very rarely "can't".

If the step is caused by the new leaf being built on the inside, build it on the outside and make up the finished line inside with an insulated stud wall. Or demolish existing single leaf wall and rebuild a new cavity wall in the right place.

If its the similar to mine, the original party wall ran into some outbuildings that were knocked down on my side. Since the other side of the party wall was damp outbuildings I treated it as an external wall, and built an inner leaf on my side. Thus where the main house party wall went into the extension there was a step - in this case a full 200mm. Quite useful in my case, since it gave me some extra depth to take a large fridge freezer. Simon.

In article , fred writes

Snip

That could be a useful idea for me; what would you use to bond the celotex to the wall? And what would you use to bond the plasterboard to the celotex?

why not buy the two bonded together already?

On Tuesday 05 March 2013 19:32 Chris Holford wrote in uk.d-i-y:

plasterboard adhesive works OK too - dot & dab styley

celotex to pb can be done with this

or just buy it ready made, tho usually uses 12.5mm pb

Jim K

In article , Tim Watts writes

Yep, ideal for the job, gap filling yet able to squish to nothing where that is what's required.

To o/p, just make sure wall is dust free and use sparingly so that it will squish out where required.

You can get ready bonded PB/insulation boards but last time I looked the range wasn't that great and some just used polystyrene as the insulator rather than superior PIR foam (celotex et al). Might be worth checking out current offerings though.