Garage Conversion

pd2006

We are thinking of getting our garage converted into an extra room. The walls are concrete is it possible to apply adhesive to make the plaster board stay on the wall or are we better putting up the timber supports and attaching the plaster board to this. Also for insulation is it possile to use the white board that you normally get in boxes to stop things been damaged, cant remember what its called. its a white board that when you break it little white balls come of it. Cant for the life of me rember what its called .

Litcagral

Polystyrene?

pd2006

Thanks for that just had a total memory block

Steve

DO NOT use polystyrene for insulation. It's extremely toxic if there were a fire and will happily help burn the house down!!!

go buy some fibreglass insulation or rockwool - any DIY store.

On external walls - use 2.5" treated studding. put insulation between studs and staple on moisture barrier (polythene sheet) then fix drywall. If not, you'll be plagued with damp / condensation problems.

On internal walls - use bonding adhesive and fix drywall direct to brickwork - alternatively, plaster and skim.

GreeBo

stevec wrote:

On external walls - use 2.5" treated studding. put insulation between studs and staple on moisture barrier (polythene sheet) then fix drywall. If not, you'll be plagued with damp / condensation problems.

What do you do if you are putting up the insulated plasterboard?
I cant figure out how you achieve a vapour barrier on the warmside of the insulation?

Steve

GreeBo wrote:

What do you do if you are putting up the insulated plasterboard?

Not sure - never used it.

GreeBo wrote:

I cant figure out how you achieve a vapour barrier on the warmside of the insulation?

I'm not an expert - I thought this was wierd as well - this is the way my house was done (8 yrs old).
Construction is: outside -> pebble dash / render -> cavity block -> stud + insulation -> polythene -> drywall -> inside.
The theory is the render keeps the water out so most of the moisture will come from inside the house. If it can get through to the insulation it will cross from the warm side to the cold side where it condenses. The same applies to loft insulation - there must be a vapour barrier on the warm side (foil backed plasterboard or polythene sheet).
Again, I'm not expert on this but it's what I've read elsewhere.

GreeBo

stevec wrote:

Construction is: outside -> pebble dash / render -> cavity block -> stud + insulation -> polythene -> drywall -> inside.

Mine is the same construction but we are thinking of redoing the external walls with insulation backed plasterboard.
The insulation that is there now is very old (18+ years) fibreglass and the bits I have seen are very thin and loose.
I was also assuming that there was a vapour barrier between the plasterboard and the insulation, but then the joins of two sheets would leave a rather "large" gap when you are talking about water vapour...

patrido

the vapour barrier on the warm side of the insulation is not to stop moisture getting in.

it is to stop vapour from inside the house (contained in the warm air) condensing when it gets cold as it travels outwards.

in the case of insulation backed plasterboard, the vapour barrier, if required, goes behind the combined slab. in other words you put the vapour barrier as far to the warm side as you practically can. in any event, the dew point should not be within the thermal liner. but farther out in the insulation layer.

interestingly both kingspan and xtratherm make a very similar product, both of which have a foil moisture barrier bonded between the slab and the insulation. kingspan say that this is enough to provide a moisture barrier, while xtratherm say that you should put in a seperate moisture barrier.

Steve

GreeBo wrote:

Mine is the same construction but we are thinking of redoing the external walls with insulation backed plasterboard.

Do you still use insulation in the space between the studding then? (in addition to the combined slab)

GreeBo

I "think" you have the option of just sticking the slab onto the wall, or using the studs, whether filled or not.

Thanks padrido, yeah I know the barrier is to stop the air in the house condensing, my fear would be that with a VB on the cold side of the insulation any condensation will be "inside" the insulation...

patrido

the temperature drops gradually from room temperature on the warm side to ambient on the cold side. if there's more than one layer of insulation, and the dew point is in an outer layer, you can put a vapour barrier outside the insulated slab, but inside the other insulation layer(s).

if the insulated slab is the only insulation you're using, then the dew point is almost certainly going to be within the single insulation layer in cold weather, and a vapour barrier should not be put on the back of that. in this case it may be better to use seperate plasterboard and insulation.

xtratherm and kingspan have free technical support to advise on this type of thing. they will do a condensation analysis and suggest possible solutions where there are problems. email or phone both companies to get a second opinion.

alternatively if you have a few hours to spare, use builddesk 3.1 to work it all out. i think they have a free trial at the moment.

services

Hi Guys

I'm in a similar sitiuation in that I have a garage attached to the side of my house and I wanna convert it into playroom. Im ok at DIY and would be willing to give this a go if its not to difficult. What would the right way to approach this project be and what steps would I need to take. Or would I be better of letting someone else worry about it and get them in.

coxy123

Services I am planning the same exercise in the next few months, so I would also welcome the steps needed. Will be replacing a garage door with window after blocking up first. Also have the headache of moving the boiler out to the external garage when this is done.

gent9662

I'm thinking the same, how best do you dispose of a Garage Door?

Steve

dclane wrote:

I'm thinking the same, how best do you dispose of a Garage Door?

Byu & Sell - works every time.
or
Post here - lots of people building garages!