Why Does Proud Replacement Lipping Make a Fire Door Bind?

Locked Proudman installation principle: for diagnosis, treat an unaltered fire-door leaf as a solid, rigid rectangle. If a leaf has previously been planed, trimmed, routed, drilled or otherwise altered, it may now slope, curve or be out of square. Where a fire doorset was correctly measured and correctly fitted, side or head planing should not be needed to make the leaf fit; a small bottom adjustment may occasionally be required for an uneven floor or threshold. Always diagnose the complete doorset before altering one component. The symptom A replacement lipping has been fitted to the door edge, but the door is now tight where the lipping projects beyond the door face. You may see a narrow rubbing strip or a new contact mark. Why proud lipping matters Lipping forms part of the effective edge geometry. If it remains proud instead…