Mercury Building Products recommend the use of an Underlay Support Tray in both Open and Closed eaves construction when a Vapour Permeable Membrane is used as the roof underlay in a pitched roof application.
VapR-free Underlay Support Trays are manufactured from polyolefin re-grind material and are available in light easy to handle rigid 1.5 metre lengths.This unique product accommodates all roof pitches and is suitable for New Build and Refurbishment.It prevents ponding and the need for a tilting fillet behind the facia board providing a clear drainage point into the gutter.
A unique hinge allows the gutter flange to be positioned at the appropriate angle of the roof. It also enables the gutter to be easily installed or replaced without the tile assembly being disturbed.
VapR-free Underlay Support Trays is waterproof and prevents prolonged exposure of the underlay to U.V. radiation, reducing long term maintenance.
VapR-free Underlay Support Tray should be positioned (rough side up) to the lower part of the rafters at the eaves with the hinge on the outside of the facia board. The 50 mm hinge is folded over the facia board and into the gutter. Alternatively it can be left flat if the gutter is to be installed at a later date.
Each length should have a minimum of 100 mm overlap and fixing should occur on each rafter by simply nailing or stapling onto each rafter. The roof underlay is positioned over the underlay support tray by a minimum of 200 mm but must not overspill into the gutter.
Double-sided adhesive tape should be used to seal the eaves carrier and underlay if requiring a completely sealed roof. Batten out roof and slate or tile as normal.