Icopal-Roof-Design

Recommended Headlaps and Sidelaps

Head laps and side laps to roofing underlays should comply with the recommendations of BS5534: 2014: Code of Practice for Slating and Tiling and BS 8000-6: 2013 Workmanship on Building Sites.

Head Laps (recommended minimum)
Pitch Unsupported Fully Supported Vertical
12.5° to 14° 225mm 150mm 100mm
15° to 34° 150mm 150mm 100mm
35° + 100mm 75mm 100mm

 

Detail Laps (recommended minimum)
Pitch Unsupported Fully Supported Vertical
Side lap 100mm 100mm 100mm
Verge 25 - 50mm 25 - 50mm 25 - 50mm
Hips 150mm 150mm   -
Valleys 300mm 300mm   -
Eaves   25mm 25mm
Ridges as table above    

NOTES:
1. Any penetrations to the underlay should be suitably sealed to prevent water ingress.
2. Underlay laps to valleys should comply with recommendations of BS 5534.
 

    Contact Icopal 0161 8654444

    Find Local Support

    To discuss your project in more detail please contact
    Your Local Area Manager

     

    Technical Support

    Telephone:

    0330 123 4585

    Email: technical.uk@bmigroup.com

     

    Sales Enquiries & Orders

    Telephone:

    0843 224 7400

    Fax:

    0843 224 7401

    Email: sales.admin@bmigroup.com

    This site uses cookies in accordance with our Website Privacy Policy. By continuing to browse the site you are agreeing to our use of cookies. To browse without the use of cookies, you can opt-out as explained in our Website Privacy Policy or adjust your cookie settings for your browser

    Icopal: We Protect Your Building