Garage conversion wall construction

[0Floz0]

Hi

I know it’s been asked plenty of times before. But, of the threads I’ve read none really answer my question.

I’m converting my garage. I’m doing it with building regs approval. The garage is attached to the property. The front wall for the door is going to have 2 skins with a cavity so no issues there. Two of them are internal 2 skin walls. That just leaves one wall which is single skin and the exterior wall.

The space is very limited within the room expected to be 2x4m when finished. So maximising width is important. The problem I’ve got is 2 piers on the single skin. So trying to keep the insulation down on these is important.

How should I construct the wall? Should it be brick, vapour layer, battens, insulation, plasterboard?

I’m going to be installing a floating floor. I assume you’d put the floor in first and then do the walls?

Thanks all

 

[^woody^]

Vapour check layer if required, is right after the plasterboard. DPM is on the back of the wall, unless it's a cavity.

Floor can go in anytime. It depends on the detail.

 

[0Floz0]

So vapour layer is on the back of the plasterboard. Assume that’s so the insulation can breathe?

The floor will be a floating one. Currently got a concrete slab. So will level up, insulate, vapour control layer then chipboard and underlay then laminate. Surely there are pros and cons to doing floor first or second?

 

[Notch7]

Surely there are pros and cons to doing floor first or second

typically with single skin garage conversions, a couple of courses of brickwork is laid next to the single skin, with a cavity gap. Then a studwork wall is formed. Later on the floor is done.

What that achieves is a cavity going down below the floor level - and any condensation and damp runs down to the bottom and can’t spread out to the floor.

If you do the floor first running it to the garage walls, theres a risk of damp spreading inwards.

 

[0Floz0]

typically with single skin garage conversions, a couple of courses of brickwork is laid next to the single skin, with a cavity gap. Then a studwork wall is formed. Later on the floor is done.

What that achieves is a cavity going down below the floor level - and any condensation and damp runs down to the bottom and can’t spread out to the floor.

If you do the floor first running it to the garage walls, theres a risk of damp spreading inwards.

If there was a lot of moisture wouldn’t it just go through the internal course? I thought that’s what the vcl on the batten wall was supposed to prevent?

 

[Notch7]

If there was a lot of moisture wouldn’t it just go through the internal course? I thought that’s what the vcl on the batten wall was supposed to prevent?

You can do it with no cavity.

line the single skin with DPM, then studwork with PIR insulation, then maybe insulation layer to stop cold spots on studwork, then vapour barrier, then plasterboard.

You need to run the wall DPM down to the existing ground, then floor DPM across floor and up wall DPM and taped.

the VCL stops internal vapour held in warm air getting to the cold wall. However damp can get through the single skin wall from outside.

 

[0Floz0]

You can do it with no cavity.

line the single skin with DPM, then studwork with PIR insulation, then maybe insulation layer to stop cold spots on studwork, then vapour barrier, then plasterboard.

You need to run the wall DPM down to the existing ground, then floor DPM across floor and up wall DPM and taped.

the VCL stops internal vapour held in warm air getting to the cold wall. However damp can get through the single skin wall from outside.

If I line the single skin with dpm won’t that stop moisture between that and the vapour layer escaping? Sorry not trying to be difficult, just trying to understand it fully.

 

[Notch7]

If I line the single skin with dpm won’t that stop moisture between that and the vapour layer escaping? Sorry not trying to be difficult, just trying to understand it fully.

The DPM on the brickwork stop damp getting to the new internal wall.

And the vapour barrier on the inside stops warm air carrying vapour getting into the internal,wall and reaching the cold extrernal brickwork.

The damp from the outside and vapour from the inside are 2 distinct elements.


What causes condensation problems is warm air laden with moisture reaching a cold surface. So a vapour barrier is fitted on the warm side of the insulation.