I’ve converted an internal garage into two rooms which has made the back utility room bigger and created a new office at the front (new stud wall / door). I’m currently digging footings to brick up half the garage door with window above. Building control have signed off electrics etc, but advised I should have put a DPM underneath the new floating floor. The builder who built the house 40 odd years ago still lives in town and confirmed the whole plot (Including internal garage) had 1000 dpm installed. I don’t really want to reverse the work completed and remove skirting boards, new floating floor Etc. So I’m not sure why a secondary DPM is required? Help and advice please!