How to Get Fire Door Mastic Into a Tight Frame-to-Wall Gap

Tight access around a fire-door frame is where mastic application becomes a real practical problem. You may have enough material in the cartridge, but not enough room to place it accurately. The answer is not simply to cut a bigger nozzle and push harder. First decide what the gap actually is Look at the frame-to-wall junction from every accessible direction before starting. Establish the depth you can see, the width variation, the presence of packers or backing and whether the visible opening continues behind the architrave. Proudman's diagnostic approach treats this as a system question. The gap is not just a channel waiting to be filled; it is part of a frame, support and fire-stopping arrangement that has to match the particular evidence. Work with the geometry you have Sika's fire-sealant instructions include cutting the nozzle to the desired bead…