Top Edge Abutment Detailing

Top Edge Abutment- Un-ventilated or Ventilated
The correct way to install the top course of tiles and the ridge tiles is dictated by whether you are trying to achieve an unventilated or ventilated top edge detail.
NOTE: Be aware there is more than one type of top edge ventilation system. 

D ridge vent filler

 
Universal ridge ventilator 

Unvented
1. Ensure underlay/breather membrane is turned not less than 75mm up abutment.
2. Install intermediate batten to secure top tile course close to junction with abutment.
3. Cut and bend tiles not less than 75mm up abutment.
4. Secure tiles to top batten with Decra Fixing Nails.
5. Seal heads of nails with Decra Finishing Kit.
6. Dress lead flashing over tile upstand and front apron area to form weathertight junction.
Tips on cutting and bending tiles

Vented with a D Ridge Vent Filler
1. Cut the roofing felt back at the top edge to allow a 5mm continuous air gap at abutment. Fit two battens side by side on both sides of the ridge using galvanised nails.
2. Cut, bend up and fix tiles close to the abutment and maintain airgap. Place the Ridge Vent Filler on the top course of tiles. Position it so that, once installed, its lower edge will fit tightly against the downturn of the Decra top course flashing. Lay a batten, not exceeding 50 x 25mm, into the tray of the Ridge Vent Filler and secure by nailing through the Filler and tile into the battens on the underside.
3. Cut and bend Decra top course flashing to form a turn up of at least 75mm up abutment. Fix Decra top course flashing over the top batten by nailing through its downturn into the face of the batten. Use 4-no Decra Nails.
4. Dress lead flashing over top course flashing upstand and over front apron area to form weathertight junction.
 

Vented with a Universal D Ridge Vent Filler
1. Cut the roofing felt back at the top edge to allow a 5mm continuous air gap at abutment. Fix two tiling battens 50 x 25mm side by side approximately 10mm back from abutment, using galvanised nails. Fix an
additional 50 x 25mm batten on top of the rearmost of the two tiling battens, in a position to suit the fitting of the top course flashing unit.
2. Turn back edge of the tile up to form 25–38mm upstand against the top tiling batten.
3. Cut and bend Decra D ridge to form a top course flashing unit with a front edge downturn of 40mm and forming a rear upstand of at least 75mm up abutment.
Position top course flashing unit over the top batten and upstand edge of tile.
Install universal ridge/hip ventilators between upturned back edge of tile and front downturned edge of top course flashing unit.
4. Fix top course flashing unit over the top batten by nailing through its downturn into the face of the batten. Use 4-no Decra Nails.
5. Dress lead flashing over top course flashing upstand and over front apron area to form weathertight junction.

Top Edge Abutment- Un-ventilated or Ventilated
The correct way to install the top course of tiles and the top edge flashing is dictated by whether you are trying to achieve an unventilated or ventilated top edge detail. 

Universal ridge ventilator 

Unvented
1. Ensure underlay/breather membrane is turned not less than 75mm up abutment.
2. Install battens so that top batten adjacent abutment supports supports bottom edge of top course tile.
3. Cut and bend top course of tiles not less than 75mm up abutment.
4. Secure bottom edge of top course of tiles to top batten with Decra Fixing Nails.
5. Seal heads of nails with Decra Finishing Kit.
6. Dress lead flashing over tile upstand and front apron area to form weathertight junction.
Tips on cutting and bending tiles

Vented with a Universal D Ridge Vent Filler
1. Cut the roofing felt back at the top edge to allow a 5mm continuous air gap at abutment. Fix two tiling battens 50 x 25mm side by side approximately 10mm back from abutment, using galvanised nails. Fix an additional 50 x 25mm batten on top of the rearmost of the two tiling battens, in a position to suit the fitting of the top course flashing unit.
2. Turn back edge of the tile up to form 25–38mm upstand against the top tiling batten.
3. Cut and bend Decra Oberon Top Course flashing to size and forming a rear upstand of at least 75mm up abutment.
4. Position top course flashing unit over the top batten and upstand edge of tile.
5. Install universal ridge/hip ventilators between upturned back edge of tile and front downturned edge of top course
flashing unit.
6. Fix top course flashing unit over the top batten by nailing through its downturn into the face of the batten. Use 4-no Decra Nails.
7. Dress lead flashing over top course flashing upstand and over front apron area to form weathertight junction.

Top Edge Abutment- Un-ventilated or Ventilated
The correct way to install the top course of tiles and the top edge flashing is dictated by whether you are trying to achieve an unventilated or ventilated top edge detail. 

Universal ridge ventilator 

Unvented
1. Ensure underlay/breather membrane is turned not less than 75mm up abutment.
2. Install battens so that top batten adjacent abutment supports supports bottom edge of top course tile.
3. Cut and bend top course of tiles not less than 75mm up abutment.
4. Secure bottom edge of top course of tiles to top batten with Decra Fixing Nails.
5. Seal heads of nails with Decra Finishing Kit.
6. Dress lead flashing over tile upstand and front apron area to form weathertight junction.
Tips on cutting and bending tiles

Vented with a Universal D Ridge Vent Filler
1. Cut the roofing felt back at the top edge to allow a 5mm continuous air gap at abutment. Fix two tiling battens 50 x 25mm side by side approximately 10mm back from abutment, using galvanised nails. Fix an
additional 50 x 25mm batten on top of the rearmost of the two tiling battens, in a position to suit the fitting of the top course flashing unit.
2. Turn back edge of the tile up to form 25–38mm upstand against the top tiling batten.
3. Cut and bend Decra D ridge to form a top course flashing unit with a front edge downturn of 40mm and forming a rear upstand of at least 75mm up abutment.
Position top course flashing unit over the top batten and upstand edge of tile.
Install universal ridge/hip ventilators between upturned back edge of tile and front downturned edge of top course flashing unit.
4. Fix top course flashing unit over the top batten by nailing through its downturn into the face of the batten. Use 4-no Decra Nails.
5. Dress lead flashing over top course flashing upstand and over front apron area to form weathertight junction.