Fire resistance to loft spaces Subject No: 7 Subject: Fire resistance to loft spaces in rooms in roof Introducing Officer: A Cross (Poole BC) Date: 3/12/1998 Approved Document B3 refers to the requirement for full 30 minutes fire resisting to floors in domestic loft conversions. A modified 30 minutes fire resisting is accepted for existing floors subject to satisfying the criteria in clause 7.7 a-e incl. However, the new second floor should meet the fr 30 requirement in full. The problem arises in converting existing loft spaces where the loadbearing ashlaring makes it less practical to board out the portion of floor/ceiling joists in the roof void areas, in the same manner as the new rooms. Suggested solutions: - 1 either board out the loft area as the new room, which may require considerable cut and fit and solid blocking between joist spaces or; 2 construct in accordance with TRADA Document Timber intermediate floors for dwellings (copy attached) relevant clauses 3.2.1.16 and 3.2.1.17, table 14 clause 3.2.1.4. (which gives alternatives) or; 3 construct in accordance with table 2 item (I), from B R E Digest 208 (copy attached). If the existing construction of the ceiling is lathe and plaster, item (2) gives protection applied from above but, there is no guidance for the non boarded part in the loft space. POLICY STATEMENT If item 1 option above is not adopted for the roof void space, the DBCTC agreed that dense mineral fibre quilt as detailed in the TRADA Doc in item 2 above would suffice subject to the existing plaster being sound.

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