Attached garage, single skin wall

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Hi everyone, I know there are numerous posts on garage conversions. I’ve read a lot of them but can’t find the answer I need.

I’m in the process of planning my conversion and width is a concern. Looking like it’ll be 1.9m wide and 4.2m long once done. However, I’m trying to avoid bricking up and around the window and just have it underneath and span the opening.

One side is internal wall so will just dot and dab that. However, what do I do about the single skin side? Wall seems pretty square but the issue I have is it has 2 piers in the middle. Thought it a bit excessive to have two piers given it’s only 4m.

What would be the best way of insulating it to minimise the depth but keep it compliant with regs? Is there a work around for the piers? Can they be replaced with something thinner? Currently they’re stacked blocks.

Thanks all
 
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Hi everyone, I know there are numerous posts on garage conversions. I’ve read a lot of them but can’t find the answer I need.

I’m in the process of planning my conversion and width is a concern. Looking like it’ll be 1.9m wide and 4.2m long once done. However, I’m trying to avoid bricking up and around the window and just have it underneath and span the opening.

One side is internal wall so will just dot and dab that. However, what do I do about the single skin side? Wall seems pretty square but the issue I have is it has 2 piers in the middle. Thought it a bit excessive to have two piers given it’s only 4m.

What would be the best way of insulating it to minimise the depth but keep it compliant with regs? Is there a work around for the piers? Can they be replaced with something thinner? Currently they’re stacked blocks.

Thanks all
Surely your pillars can/will disappear within the insulation depth. You will need 150mm on the single skin and 50mm minimum across the piers.

Problem solved (cash accepted).
 
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Surely your pillars can/will disappear within the insulation depth. You will need 150mm on the single skin and 50mm minimum across the piers.

Problem solved (cash accepted).

Thanks. Is 150mm really the minimum? Is there nothing that can be done with the piers? Ie removing them and replacing them with a thinner alternative? Would you just attach the insulation directly to the wall? I read I need a breathable dpm to prevent condensation but just trying to maximise everything width wise. 150mm + 12.5mm plasterboard is getting on the larger side of what I was hoping for.
 
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I'd remove them. Ensure the wall is strapped to the roof joists/ bottom chord at those places

80mm Celotex for the wall.
 
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I'd remove them. Ensure the wall is strapped to the roof joists/ bottom chord at those places

80mm Celotex for the wall.

When you say strapped, what would the fixing of choice be? Would building regs sign off the conversion without a pier? They’re actually falling off already as they must have been installed poorly. Can literally pull the top two off the stack.
 
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When you say strapped, what would the fixing of choice be?
Galv twisted straps for individual joists or bent straps for a wall plate.

Don't bother with 80mm Celotex. It's a pain to get hold of. If you have the room always opt for the easily available 100mm. You won't regret it.
 
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Thanks. Is 150mm really the minimum?
Any amount is an improvement. However, I believe 120mm was recommended on our last single skin upgrade. A lot depends on the overall insulation content and overall heat loss. As long as you can control the cold bridge primarily (80mm would cut it) then any additional thickness is down to design.
 
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