Why don't you carry out wind load calculations on roofs less than 100m2?
- Read time: 1 minutes
- Date: 07 May 2025
- Flat Roofing
To ensure this is valid for even the most challenging location in the UK, we have calculated using a 'worst case scenario'. We have carried these calculations out for roofs up to 3m high (single storey), and roofs up to 10m high (3 storeys high).
The following generic fixing specification applies:
PIR Insulation Board Attachment (applies to both 3m & 10m high buildings) Board Size
2400 x 1200 - 11 fasteners per board
1200 x 1200 - 6 fasteners per board
1200 x 600 - 4 fasteners per board
PVC Membrane Attachment - 3m high buildings (membranes up to and including 2m wide)
Corner & Perimeter zones to be 1m wide from and around the roof perimeter.
Membrane lap fasteners within these zones to be fixed at 150mm centres
Membrane lap fasteners elsewhere (field zone) ≤to be fixed at 350mm centres.
PVC Membrane Attachment - 10m high buildings (membranes up to and including 1.2m wide)
Corner & Perimeter zones to be 2.5m wide from and around the roof perimeter.
Membrane lap fasteners within these zones to be fixed at 150mm centres
Membrane lap fasteners elsewhere (field zone) to be fixed at 350mm centres.
For membranes ≥1.2 and up to ≤2.1m wide.
Corner & Perimeter zones to be 2.5m wide from and around the roof perimeter.
Membrane lap fasteners within these zones to be fixed at 200mm centres with a centre line of fixings.
Membrane lap fasteners elsewhere (field zone) to be fixed at 250mm centres.
As a guide for a roof of 100m² and 3m high you will need approx. 300 insulation fasteners and 200 membrane fasteners. For a roof the same size but 10m high you will need approx. 400 insulation fasteners and 400 membrane fasteners.
NB: It is assumed the structural deck is of a suitable material. If in doubt please contact us.
If your roof is outside of the above scope, please contact us.
