Structure: Approved Document A

O N L I N E V E R S I O N A1/2 Section 2B: Sizes of certain timber members in floors and roofs for dwellings. Areas at risk from house longhorn beetle Sizing of members House longhorn beetle 2B1 Guidance on the sizing of certain members 2B2 In the geographical areas specified in in floors and roofs is given in ‘Span tables for Table 1, softwood timber for roof construction solid timber members in floors, ceilings and roofs or fixed in the roof space, including ceiling joists (excluding trussed rafter roofs) for dwellings’, within the void spaces of the roof, should be published by TRADA, available from Chiltern adequately treated to prevent infestation by the House, Stocking Lane, Hughenden Valley, High house longhorn beetle (Hylotrupes bajulus L.). Wycombe, Bucks HP14 4ND. Guidance on suitable preservative treatments Alternative guidance is available in BS EN 1995- is given within The Wood Protection Association’s 1-1:2004 Design of timber structures with its UK manual ‘Industrial Wood Preservation: National Annex and additional guidance given in Specification and Practice’ (2012), available BSI Published Document PD 6693-1:2012 and from 5C Flemming Court, Castleford, also BS 8103-3:2009 Structural design of low- West Yorkshire, WF10 5HW. rise buildings, Code of practice for timber floors and roofs for housing. Table 1 Areas at risk from house longhorn beetle Geographical area In the Borough of Bracknell Forest the parishes of Sandhurst and Crowthorne. The Borough of Elmbridge In the District of Hart, the parishes of Hawley and Yateley The District of Runnymede The Borough of Spelthorne The Borough of Surrey Heath In the Borough of Rushmoor, the area of the former district of Farnborough The Borough of Woking Structure Approved Document A 12 O N L I N E V E R S I O N