Frank123

This is amazing, Thank you @Icevergeyou were spot on with the joist size and spacing too.

Thanks @PeterW yeah will be clad with cement board underneath. I’m probably overthinking it, anything will be better than the solid uninsulated walls of the existing structure.

Thanks @Iceverge I appreciate your help. We will be using caberdeck and the d4 adhesive.

Thanks @Iceverge will consider that. At the moment it’s just the full fill cavity insulation. Wanted to check the VCL detail before insulating. I have building control coming out Wednesday so will run both options past them but the non-shrinkage makes sense as this could be a big thermal bridge.

Hi Dave The joists pictured are for the first floor. In effect the section under the overhang will be a cold roof upside down? Just don’t know if VCL should go below the joists or above. The pitched vaulted roof above first floor will have 165mm PIR insulation with 30mm PIR taped to form VCL Don’t know if this will help?

Hi, we are currently self building an extension with standard block cavity walls on the ground floor and timber frame on the first floor. We have an overhang over an alleyway that is supported on blocks one side and steel the other. Do I need a VCL under the overhang section? The internal walls will be taped 30mm PIR This is a crude sketch of the detail I was thinking. Inner skin will continue to top of joists. Insulation in overhang floor will tie in with cavity insulation. I’ll also attach a photo for reference Thanks