Over Fascia Ventilating System (OFVS)
Function:
OFVS10 and OFVS25 Over Fascia Ventilating System for tiled roofs to provide:
1. Eaves level roof void ventilator.
2. Hinged underlay support.
3. Bird excluder.
4. Tile clipping (clip extra).
5. Insect Inhibitor.
6. Drip into gutter.
OFVS10/L and OFVS25/L Over Fascia Ventilating System for slate roofs (including interlocking slates and plain tiles) to provide:
1. Eaves level roof void ventilator.
2. Hinged underlay support.
3. Insect Inhibitor.
4. Drip into gutter.
Complies with the requirements of Part F2 of the Building Regulations 1995 and the recommendations of BS 5250: 1989 for eaves level ventilation in slate and tiled roofs over 15° pitch.
Material: Polypropylene
Free Vent Area: OFVS10 and OFVS10/L:
Equivalent to 10mm continuous opening.
OFVS25 and OFVS25/L:
Equivalent to 25mm continuous opening.
Colour: Black
Range: There are 4 types of OFVS strip available details of their general characteristics, ventilation capacity and usage are as follows:
|
PRODUCT CODE |
VENTILATION |
ROOF FINISH |
|
OFVS1O* |
10mm continuous |
Profiled Tiles |
|
OFVS1O/L |
10mm continuous |
Flat Tiles and Slates |
|
OFVS25* |
25mm continuous |
Profiled Tiles |
|
OFVS25/L |
25mm continuous |
Flat Tiles and Slates |
|
*These items have integral bird excluder |
Fixing:
Installation by the roofer in new build and re-roofing work to slated and tiled roofs from 15° to 70° pitch.
Note: Take extra care to prevent pooling below 23°.
Nailing:
3.35mm diameter 65mm long galvanised steel nails at 200mm centres (ring shank nails; Scotland and N Ireland). For roofs with ridges over 7.2m and in areas of high exposure, calculate fixings in accordance with BS 5534.
Jointing:
The system's components have interlocking joints for forming continuous straight lines. Mitre the strips at hips and valleys. At inner valley joints, fix over a separate flashing extending at least 150mm on each side of the joint.
