design detail to mansard
The following illustrations and text explain the common main tile design details that can occur on refurbishment and new work to mansard.
Flashing to mansard roof
To avoid tile cutting the distance from the face of the tile batten to the window frame should ideally be 125mm, or in increments of 82.5mm to minimise tilecutting to a half tile module.
Handed external angle tiles are fixed in alternate courses up the external corner. Cutting of these should be avoided.
Fix a vertical lead flashing, approximately 200mm wide, turned into a rebate just behind the face of the tiles and terminated with a welt.
The first counterbatten should be positioned approximately 20mm in from the end of the tile batten to prevent the end nail fixing from splitting the tile batten. (This detail requires a very wide sill and works better with a creasing tile sill detail)
Mansard Roof with mansard tiles
Ensure that a clear ventilation path is maintained from eaves to ridge whiere insulation is positioned between the rafters. Lap the roof underlay over the mansard underlay by minimum 150mm.
Establish the correct number of courses of mansard tiles to maintain minimum headlap of 65mm.
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