Do insulated plaster board sheets have to be skim coated or will just paint do?

wall

Hello,
I am going to insulate the gable end wall in my kids bedroom, coldest room in the house, i want quick & easy job (like everyone), the wall is 10ft x 8ft, i will stick up 2 and half sheets of insulated plasterboard, is there a tape one can buy to put over the joins so i can just paint it or will the joins show tru the paint?

MicktheMan

Where are you putting the vapour control layer?

wall

Hi Mick,
if i knew what a 'vapour control layer' was i may be able to tell you where i would stick it.

MicktheMan

Start here

Buford T Justice

At the very least, you will need to joint and tape the boards to cover the joints properly.

BryanF

MicktheMan wrote: »

Start here

Mick,
that's an interesting series of posts. so (slightly off topic, but probably relevant to the OP) should any dry-lining measures that are grant aided incorporate some sort of vapour barrier and if so, how does this work with insulated plasterboard?

wall

So, without a vapour barrier, the wall is going to get mouldy? so are tens of thousands of houses that were built or revamped over the last ten or more years mouldy now?

MicktheMan

BryanF wrote: »

Mick,
that's an interesting series of posts. so (slightly off topic, but probably relevant to the OP) should any dry-lining measures that are grant aided incorporate some sort of vapour barrier and if so, how does this work with insulated plasterboard?

It doesn't. And in a few years there will be grants to remove the insulated plasterboards from the mould infested houses (that is if there's any money left!).
I asked about the vcl to highlight the issue of trapped moisture.:)
Insulated slabs have a foil back which in effect are moisture traps when installed.
Imo, internal drylining is a bad idea but if no other way then breathable products should only be used, with breathability increasing from (cold) wall to internal room. This would include an intelligent vcl on the warm side of the insulation, counter batton and plasterboard. More space is taken up but healthier house.

MicktheMan

wall wrote: »

So, without a vapour barrier, the wall is going to get mouldy?

No, there is still a very high risk because of the foil on the back of the insulated slabs.

wall wrote: »

so are tens of thousands of houses that were built or revamped over the last ten or more years mouldy now?

You'd be surprised how many are!
Ask yourself this. How many houses have some/severe condensation on windows after a cold night. The same level of moisture can form at the back of the insulated slabs where it cannot dryout easily.

wall

At the very least, you will need to joint and tape the boards to cover the joints properly.[/QUOTE]
Has anyone tried this, will the paint hide the tape or is there a special heavier paint one can use for this?

Buford T Justice

wall wrote: »

At the very least, you will need to joint and tape the boards to cover the joints properly.

Has anyone tried this, will the paint hide the tape or is there a special heavier paint one can use for this?

The whole idea is that it leaves the wall smooth so it can just be painted.

Check out some of these videos and see if it helps you're understanding, but its not something you want to consider doing yourself if you're not familiar with the process.

BryanF

MicktheMan wrote: »

It doesn't. And in a few years there will be grants to remove the insulated plasterboards from the mould infested houses (that is if there's any money left!).
I asked about the vcl to highlight the issue of trapped moisture.:)
Insulated slabs have a foil back which in effect are moisture traps when installed.
Imo, internal drylining is a bad idea but if no other way then breathable products should only be used, with breathability increasing from (cold) wall to internal room. This would include an intelligent vcl on the warm side of the insulation, counter batton and plasterboard. More space is taken up but healthier house.

i totally agree, i generally spec a variation of that, whats interesting is the term VB required on all dry-lining something I've never heard mentioned from a builder with regards to the dry-lining grants!!

whizbang

most of the insulated plasterboard has vapour barrier already built in.
If you seal ends and edges correctly the vapour cannot get through the plasterboard to cause condensation. If its coming in thro the blockwork then arent you better off sealing off the interior from this???

If you dont tape joints they will show thro paint after a few years. but the fixings will also, and you cant really do much about that.

MicktheMan

whizbang wrote: »

If you seal ends and edges correctly

How do you do this such that it is vapour tight?

whizbang wrote: »

the vapour cannot get through the plasterboard to cause condensation.

What about hanging pictures, shelves etc or installing electrical sockets. All these will puncture the vcl and allow moisture through. Once through its trapped.

whizbang wrote: »

If its coming in thro the blockwork then arent you better off sealing off the interior from this???

Absolutely not. Concealing a water ingress problem with drylining of any kind is foolish in the extreme.