Insulated plaserboard onto plastered walls

Payton

My brother inlaw is putting up sheets of insulated plaster board, and he's looking for the best way to fix them to the wall. He's been told to just put "bonding" on the back of the slab but personally I wouldn't, I've told him that there is a type of mushroom fixing that is available. Can some one advise us?

Davy

Ye usually done with mushroom fixings

3ndahalfof6

depends on the wall, if your fixing to both sides of the wall drilling it and using mushroom fixings could weaken the wall, interior walls dib dab works fine, exterior walls mushroom fixings,

im no expert but it is what I would do.

Payton

It's going onto an exterior wall so it should be solid when fixed, I'll tell him to get those mushroom bolts.

3ndahalfof6

Payton wrote: »

It's going onto an exterior wall so it should be solid when fixed, I'll tell him to get those mushroom bolts.

yes exterior walls I would be using mushrooms, it is less hassle and quicker, in the sense of lining things up.

5T3PH3N

Get the steel mushroom fixings, the plastic type are useless!

czgalway

them mushrooms are ok but often they wont tighten the slab back to the wall and also its easy to tear the paper on the slab when tryin to get the mushroom flush with the surface there is also metal fixings like a express nail with a round head the same size as the mushroom one and they are much better,and no more expensive https://encrypted-tbn1.google.com/images?q=tbn:ANd9GcTg-XS-34tx8rxViPdKFvTxxYgfJt9E_kefV4Rvqj8srvRLcazk take my word on them ive put up hundreds of slabs

3ndahalfof6

5T3PH3N wrote: »

Get the steel mushroom fixings, the plastic type are useless!

yep I agree, plastic are ok on a small area, interior.

One shot on kill

czgalway wrote: »

them mushrooms are ok but often they wont tighten the slab back to the wall and also its easy to tear the paper on the slab when tryin to get the mushroom flush with the surface there is also metal fixings like a express nail with a round head the same size as the mushroom one and they are much better,and no more expensive https://encrypted-tbn1.google.com/images?q=tbn:ANd9GcTg-XS-34tx8rxViPdKFvTxxYgfJt9E_kefV4Rvqj8srvRLcazk take my word on them ive put up hundreds of slabs

Ye there called steel mushrooms. Just make sure there long enough and don't bait the bollox out of them when fixing. You want at least 50mm in the wall or more if you can.

Merch

I've been advised of bonding insulated plasterboard to interior walls.

When I saw this thread, thought Id follow it as I'm interested to do this at some stage.
I'd planned on doing it on the internal walls, there is existing plasterboard there, so

personally I was going to bond it and do a few mushroom fixings, to support it.

My main concerns are, will this support the insulated backed plasterboard?
and
more so,
will I change the temperature in the existing spaces behind the current plasterboard if i add the new insulating material/layer (I presume reduced temperature will occur as it will be insulated from the heat inside, ie I want less heat transfer than previously through the new material) will this affect moisture/condensation and possibly mould growth.
I dont think so, as if I am reducing the temp in those spaces between the existing plasterboard and exterior surface of the wall, then mould might be less likely to grow? do I have that right?
or will colder temp mean more condensation in those spaces?

plasteritup

ok,use the bonding compound not on the back of the slab but on the wall only if the walls are out of plum,then stick the slab to the dabs using a long straight edge to tap the board plum and level(this only if he is bothered about the walls being perfect)the put maybe 4 plugs/metal mushrooms thru the board after compound has gone off.

other than that just plug the wall without the compound using the metal fixings.

Lorgach

5T3PH3N wrote: »

Get the steel mushroom fixings, the plastic type are useless!

I agree with 5T3PH3N... The steel ones are best

Merch

the bonding recommended to me was some kind of glue/adhesive, from what i gathered it was spray on

Villaines

plasteritup wrote: »

ok,use the bonding compound not on the back of the slab but on the wall only if the walls are out of plum,then stick the slab to the dabs using a long straight edge to tap the board plum and level(this only if he is bothered about the walls being perfect)the put maybe 4 plugs/metal mushrooms thru the board after compound has gone off.

other than that just plug the wall without the compound using the metal fixings.

I still don't get how there is no cold bridging caused by using all these metal plugs.

harry21

Why use insulated plasterboard on internal walls? Sound proofing?

Merch

Villaines wrote: »

I still don't get how there is no cold bridging caused by using all these metal plugs.

well there will be cold bridging, but the surface area of a few metal plugs is small compared to the surface area of insulation, the benefits of the insulation would have to outweigh the losses of the plugs, the fewer used the better I suppose.
It can be calculated though, I'd have to look it up but cant recal which units

harry21 wrote: »

Why use insulated plasterboard on internal walls? Sound proofing?

Well if you were to add insulation (for heat transfer reduction), then you want the surface finish to look better than that of insulation.

The reason I consider it is,
External insulation is expensive, does the cost of installation outweigh the savings? if so by how much? if its not being calculated then why bother pay someone to do it? the benefits may be there but without knowing how much you are saving, its hard to not wonder if you are saving anything, you could just pay the extra money to heating bills at no loss and be able to pay it piecemeal opposed to in one lump, for which you may have to take a loan to pay, hence interest and added cost.

If internal insulation can be done by the average DIY'er whats the cost?, probably less than paying someone else, but the benefits while likely there also, may be more given that you could do it piecemeal as you can afford.

My only concern is
What is the effect of condensation between any existing plasterboard dry lining and outer wall and does this create conditions for mould or anything that might deteriorate the plasterboard/wood battens?
or cause health problems?

3ndahalfof6

harry21 wrote: »

Why use insulated plasterboard on internal walls? Sound proofing?

If they are block for heat , not so sure about sound, if they were stud walls insulation would of been put in place before slabbing,

am I missing something here?

Merch

3ndahalfof6 wrote: »

If they are block for heat , not so sure about sound, if they were stud walls insulation would of been put in place before slabbing,

am I missing something here?

Not all dry lining is insulated or insulated as well as it could be.
A lot of it is for the surface finish, while there may be some improvement in heat transfer reduction it could be improved by adding to the insulation.

Not as good if it was calculated and done at the time it was built but there you have it.

harry21

I'm on about internal walls, not the internal leaf of an external wall.

Payton

We put the boards (7) up with the steel mushroom bolts, very easy to do. Thanks for the advice guys :-)

Merch

harry21 wrote: »

I'm on about internal walls, not the internal leaf of an external wall.

Thats what i thought you meant alright