Hopking

Hi proDave. I agree that that method will work for matching to the existing wall thickness but i would like the thinnest walls possible in the extension to get as much space as possible out of it. I've been a chippy for 5 years now but I've only worked in loft conversions and garden rooms. From my experience with this work I have built exterior walls that have just been 4x2 cladded with OSB then felted and battened ready for cladding or tiles. Is a second skin or a service void necessary in ground floor extensions or can I just build a single skin timber wall that will have a finished thickness of around 150mm?

I have just started construction on my own timber frame extension and need some advice on wall thickness. I know that wall thickness is determined by U-value but what I am unsure about is the minimum wall thickness achievable. The houses existing walls are 350mm thick but as the extension isn't massive I want to have the thinnest walls possible to conserve space and pass building regs. Also perform well in with heat loss and sound proofing. The exterior will be cladded so no masonry outer skin. Am I able to do a single skin timber wall? I would prefer not to have to pay for a calculation for the necessary wall thickness so any advice on how to work out the u-value would be great. Any info and recommendations for insulation much appreciated. Happy to answer any info that's needed Thanks in advance