With the unique interlocking fixing system - Envirotile has unrivaled performance and is quick and easy to install. They are fully guaranteed to perform against severe UK wind loads in any designated zonal area within the UK and we offer a free replacement service for dislodged roof tiles caused by gale force winds up to 65mph (subject to our Terms & Conditions). The Envirotile 8 Fix proven performance guarantee is in addition to our standard 40 year product guarantee.