- Excellent nail and tear strength
- Complies with BS5534:2014
- Entirely watertight
- Warm roof structures
- Cold roof structures
Full installation details are available on request from the Technical Department.
- Harcon NPU must be installed and fixed in accordance with the Certificate holder's instructions and the relevant recommendations of BS 5534:2003 and BS 8000-6:1990. Installation can be carried out under all conditions normal to roofing work.
- The product should not be laid directly onto insulated sarking board but can be laid on timber sarking in conjunction with counter battens.
- The lining, when installed as a cold ventilated roof system, is fixed in the traditional method for roof tile underlays, i.e. draped between the rafters, or used in conjunction with counter battens.
- When used in a hybrid warm roof specification, a ventilation gap of at least 20mm between the insulation and the underlay should be allowed. A vapour control layer should be used on the underside of the insulation.
- Laps should be installed to shed water out and down the slope.
- Overlaps must be provided with the minimum dimensions given in the below table.
- Hips and valleys should be covered with a 600mm wide strip of the product.
- In closed eaves constructions, eaves guards should be used.
|Roof Pitch (°)
|Horizontal Lap (mm) Partially Supported
|Horizontal Lap (mm) Fully Supported
|Vertical Lap (mm)
|12.5 to 14
|15 to 34