Building Control have instructed that I restrain the laps of the membrane – how is this achieved?

In accordance with BS5534 the laps of a roofing underlay can be restrained in 3 ways: 1. Restrained with an integrated or external tape. 2. Restrained with a ‘fly’ batten. 3. Restrained using the existing tile/slate batten line. The most cost-effective and quality-assured way of achieving this is by installing a roofing underlay with a double integrated tape system.