I'm beginning to worry about the way that I attached my insulation boards to the garage walls. The garage is water-tight, and at the request of the BCO, I laid a damp proof membrane right across the floor, and extended it up and around the floor surface, such that all of the wall panels (polyfoam and normal plasterboard) are sitting on the edges of the DPM.
Due to bowing of my polyfoam boards, I decided to attach them to the walls mechanically. So I used 25x38mm kiln dried wood to make supports at the edges of each 1200mm wide board, with further supports at 600mm centres vertically, and horizontally across the top. 25mm was the depth - so the boards are literally about an inch away from the single leaf brick walls. The plasterboard was dot and dabbed up.
I read somewhere that I should have treated the wood, due to moisture build-up in confined spaces. Is this correct? And are the wood supports just going to rot and then let my whole new room's interior just fall apart? The air space at the back of the wall panels is not airtight - i.e. None of the wood fits perfectly (by design, as it was easier to fit that way), and I can leave a gap in the loft insulation to allow more airflow. at the edges of the room.
Thanks
John