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On my bungalow extension I parted existing roof tiles and fixed diminishing trusses up the rafters (what a nightmare that was).
The trusses are at 600 centres, existing rafters are at 400 centres.
The roof intersection new to old forms two valleys, each 7 metres long.
Each roof structure has a different pitch, difference 10 degrees, therefore local roofing merchants sold me grp dry valley unit, to handle the pitch issue.
Installation instructions mention support for the grp units can be via inset valley boards or alternatively on 6mm ply laid over the rafters. Obviously with these valley lengths the ply overlaid would be the preferred option - otherwise I need to cut 28 valley boards for the existing rafters and 12 valley boards for between the diminishing trusses.
Is 6mm ply substantial enough to fix the ends of tile battens to? Assume the 6mm increase in tile batten height where it meets the ply board won't be enough to make the tiles kick up?
If anyone has tackled a similar 'challenge', your advice would be much appreciated.
The trusses are at 600 centres, existing rafters are at 400 centres.
The roof intersection new to old forms two valleys, each 7 metres long.
Each roof structure has a different pitch, difference 10 degrees, therefore local roofing merchants sold me grp dry valley unit, to handle the pitch issue.
Installation instructions mention support for the grp units can be via inset valley boards or alternatively on 6mm ply laid over the rafters. Obviously with these valley lengths the ply overlaid would be the preferred option - otherwise I need to cut 28 valley boards for the existing rafters and 12 valley boards for between the diminishing trusses.
Is 6mm ply substantial enough to fix the ends of tile battens to? Assume the 6mm increase in tile batten height where it meets the ply board won't be enough to make the tiles kick up?
If anyone has tackled a similar 'challenge', your advice would be much appreciated.