Hello again All and thank you for the replies for my DPC/Gas barrier questions. I am now ready to plan how to close the cavity at the sides of a roller shutter door which will have an internal shutter box. Do I leave the cavity open and hope that I can positiob the roller shutter runner in the gap or do I need to use special cavity closing blocks on the inner leaf with a vertical DPC???
many thanks again,
Lee Hewitt