Regs for Required Insulation for Possible Single Skin Extension to Property If you want to know how your DIY projects could be affected by building and planning regulations, click here to post questions and view answers

[Kelboy]

I am looking to build a small single storey side extension to my property. I am trying to find out if the externals walls have to be cavity or can a single skin layer of concrete block be used and then an optional way of insulating on the inside be used to pass the required building regs? I am thinking of some kind of wood baton/stud work with insulation then plasterboard on top with skim coat? I am struggling to find any clear guidance to this online. Thanks

[welsh brickie]

building regs will require you to build a cavity wall, how wide the cavity needs to be will be up to building control