600 mm Frame Fixing Centres: What the Spacing Actually Controls

600 mm Frame Fixing Centres: What the Spacing Actually Controls Related diagnostic: The Missing Frame Fixing Behind the Architrave: A Hidden Movement Fault explores the connected frame-fixing or gap-measurement issue and helps compare the evidence before choosing a repair. "600 mm centres" matters because frame fixings create the restraint pattern. The useful question is where the effective restraint points are and how much unsupported span exists between them. What the pattern is telling you Falcon FPP-IM-1401-D gives an installation example with top and bottom jamb fixings within 200 mm of the ends and intermediate fixings at centres no greater than 600 mm. That is evidence for that arrangement, not a universal recipe. Map the fixing pattern and inspect whether each fixing is actually supported by sound substrate and packing. For frame faults I would map effective restraint, not just visible…