It is always better to avoid finishing with small tile cuts at hips, valleys and other abutments on the roof as they are particularly vulnerable to removal by wind uplift. Often with good setting out - utilising the available shunt in the tiles and half tiles where they are available - it is possible to avoid this situation. However, it is not always possible to avoid small tile cuts at the perimeter of a roof and a suitable method is required to ensure they are adequately secured against the wind.
The NHBC currently accept that small cut tiles at hips, valleys and other abutments can be fixed either using a suitable adhesive or a minimum of two mechanical fixings. Redland's recommended and guaranteed method is to use mechanical fixings although the practice of using a suitable adhesive for the bonding of small cut tiles to the adjacent mechanically fixed tile can also be an acceptable solution - albeit dependent on the workmanship of the site operative - if a suitable adhesive product is used in accordance with the adhesive manufacturer’s instructions.
Redland supplies a range of mechanical fixings including Head (C-Clip) (9518), Tail Clip (9519/9522) and Kro-Clip (9142) specifically designed for securing cut tiles.
The table below summarises Redland's minimum fixing recommendations for securing small tile cuts in both dry-fixed and wet-bedded situations at hips, valley and other abutments. These recommendations are designed to meet current NHBC requirements. Please note, however, that where Redland products are being specified and used as part of a project covered under the terms and conditions of Redland’s premium 15 year SpecMaster Guarantee, small tile cuts must be fixed in accordance with the SpecMaster specification.
Minimum mechanical fixing of small tile cuts to comply with NHBC Buildmark Warranty requirements
The following recommendations should be followed where the "perimeter" tiles happen to be small cut tiles which cannot be head fixed through the existing nail-hole(s). Please note for hips, valleys, roof windows, bonding gutters, secret gutters and solar panels if a nail or screw can be used as a head fixing of the small cut tile, either through an existing nail-hole or a newly drilled hole, then one of the required two fixings can be a Redland-specified nail or a screw instead of one of the clips specified below. Numbers in parentheses represent Redland product codes for ordering purposes.
i.e. small cut tile with raking cut edge increasing to eaves.
Dry Hip/Rapid Hip/Uni-Vent Rapid Ridge/Hip – Two fixings required: (1) Kro-clip(9142) at cut edge; (2) Mechanically fixed hip tile.
Two fixings required: (1) Head (C-Clip) (9518) at head of cut tile; (2)Kro-clip (9142) at cut edge.
i.e. small cut tile with raking cut edge decreasing to eaves.
Dry Valley/Open Rapid Flashing Valley – Two fixings required from: (1) Head (C-Clip) (9518); (2) Kro-clip (9142) at cut edge; (3) Tail Clip (9519/9522)*.
Two fixings required: (1) Head (C-Clip) (9518) at lead of cut tile; (2) Kro-clip(9142) at cut edge.
Verges and other straight abutments (e.g. roof windows, side abutments, solar panels) i.e. small cut tile with vertically straight cut edge.
Ambi-Dry Verge/Rapid Verge – Two fixings required: (1) Nail or screw at head of cut tile; (2) Verge Clip or Batten-End Clip at tail.
Roof Windows, Bonding Gutter, Rapid Flashing Secret Gutter, Solar Panels – Two fixings required: (1) Kro-clip (9142) at head of cut tile; (2) Verge Clip at tail.
Side abutments (Rapid Flashing or Lead) – Two fixings required: (1) Nail or screw at head of cut tile; (2) Cover flashing provides second fixing.
Verges – Two fixings required: (1) Nail or screw at head of cut tile; (2) Verge Clip at tail.
* 9519 Tail Clip - For all Redland metric tiles except the Slate 10 range tiles; 9522
Tail Clip – For Slate 10 range tiles (thin leading edge tiles).
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