As far as fire protection is concerned, most local authorities have adopted the Dorset Model for guidance on fire protection for thatched roofs. This will be a necessity when either constructing a new house or a new extension in order to comply with Local Authority Building Regulations.
In essence, this requires the minimum of a 30 minute fire resistant barrier in the form of a rigid board which is placed immediately above the rafters. This is held on with vertical counter batons and all joints are sealed with a intumescent mastic. This is then covered with a breathable membrane on which horizontal batons are fixed at approximately 250mm centres.
It is also necessary to have a domestic mains and battery power interlinked smoke detector alarm system with one detector fitted in the roof void to comply with Approved Document B to B.S.5839 Pt.6:2004.