Eaves Ventilation

• Working Procedure

1. The fascia board should be fixed on the rafter ends, so that the vertical inside height in millimetres above the rafter is as per the table below.

Note: The figures in the table are nominal and are based on a 20mm fasciaboard. Where there is no fasciaboard a support batten must be provided.

2. Position and nail an eaves vent tray centrally over the rafter and allow the sides to overlap where necessary. Make sure the front lip overhangs the fasciaboard and can discharge into the gutter.

3. Roll out the underlay in the normal manner remembering to over lap the underlay by the required lap for the pitch*.

*Refer to the Forticrete Design Guide or current BS5534.

Note: It is not necessary to dress the underlay into the gutter.

Note: On lower pitches it may be necessary to install a continuation piece,as shown in the diagram,that extends up the roof to allow the insulation to be tucked into the eaves without obstructing the airflow from outside.

4. Nail a universal eave filler strip to the top of the fascia or support batten using 50 x 3.35mm aluminium nails. A minimum of three nails per strip should be used. Position and fix the first tiling batten so that the tails of the tiles/slates overhang the fascia by approx 50mm.


5. Generally starting on the right hand side of the roof lay the eaves course of tiles opening or closing the shunt on the tiles so that the desired measurement is achieved between verges, valleys or hips.

Note: It may be necessary to use T½ tiles or slates (or bonded double width tiles if constructing a mitred hip with Minislates) to avoid small unfixed tile/slate pieces.

* Add 6mm for a ply tilting fillet