Add studwork & cavity to form extension inside enclosed yard.

12 Sep 2019
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United Kingdom
My daughter has a 1930’s terrace house with an enclosed solid brick yard (3 sides) 230mm brick. 4.7m x 3.1m

The yard currently has a Perspex roof.

We hope to convert this yard into a building control approved full single story extension.

If we build studwork, plus a cavity plus insulation inside the existing brickwork will that be satisfactory for building control?

If so, any specific dimensions required eg 50mm cavity, 100mm stud with 100mm insulation inside the stud.

What foundations will be required for the studwork?

The rear wall which currently has a single door will be nearly fully opened up with full height glazing and patio or sliding doors.

I will probably come back to this thread with more questions.

Any other main points I should consider at this stage?

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You could upgrade the walls internally with insulated studs, plasterboard and skim providing you meet the required u-values.

Assuming this ‘yard’ has an existing concrete floor, you can build the studs off that without needing any additional foundations. Bear in mind the floor will need to be upgraded to bring that up to thermal standards.

What are you planning for the roof... flat or pitched bearing in mind that too would need to be insulated.

Any photos of what you currently have?
This sound more or less like a garage conversion, so review some of those threads to read up on how walls and paces can be converted relatively simply.
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Thanks for the replies. Existing yard image attached as suggested by @DevilDamo

Looking at some online material regarding garage coversion here are two links suggesting materials required. Any toughts on what has been suggested by

Knaufinsulation 6mm plywod behind stud, VS 50mm battens suggested by Kingspan

0mm Vapour barrier
6mm Plywood (Kingspan seem to suggest 50mm battens)
100mm Stud
0mm Vapour barrier
12.5mm Plasteroard
12mm Plaster


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