Cavity wall width reduction ideas please

[monet2088]

Hi
We are have planning permission for a 2 storey side extension
The outside of the external wall must match the existing house bricks which could be standard bricks or brick slips that match the existing house bricks
Traditionally the wall would consist of brick/cavity/ breeze block inside
But we want to get get as much width as possible inside
So
1. What is the minimum width of cavity we can get away with and how would we do it
2. Is there any option to reduce the width of the external wall that would be the traditional brick/ cavity/breeze block
Thanks

 

[johnny2007]

It's only going to be a couple of inches at best.
Not worth the hassle imo.

 

[monet2088]

Without a long and boring explanation every extra inch of internal garage width will count hence my post
so any practical suggestion would be appreciated and very helpful
Thanks

 

[johnny2007]

50mm

 

[freddiemercurystwin]

Probably SIPs panels + carrier board + brick slips, around 250mm. Thinnest traditional cavity wall is 290mm if you can get away with a 75mm inner leaf otherwise 315mm (100mm inner leaf), though each involves achieving a 10mm cavity between the insulation and brick skin which is easier said than done.

 

[cdbe]

I presume you know you can remove the outer skin of the previous external wall?

 

[hunbahubba]

Speak to your architect but the best solution may be a system built wall finished in brick slips, making it possible to go much thinner than would be the case with a cavity wall while still meeting the required u value for building regs