Section 2B Sizes of certain timber members in floors and roofs for dwellings. Areas at risk from house longhorn beetle

Sizes of certain timber members in floors and roofs for dwellings. Areas at risk from house longhorn beetle  

  1. Sizing of members
    1. House longhorn beetle

      Sizing of members

      2B1. Guidance on the sizing of certain members in floors and roofs is given in 'Span tables for solid timber members in floors, ceilings and roofs (excluding trussed rafter roofs) for dwellings', published by TRADA, available from Chiltern House, Stocking Lane, Hughenden Valley, High Wycombe, Bucks HP14 4ND. Alternative guidance is available in BS EN 1995- 1-1:2004 Design of timber structures with its UK National Annex and additional guidance given in BSI Published Document PD 6693-1:2012 and also BS 8103-3:2009 Structural design of low- rise buildings, Code of practice for timber floors and roofs for housing.

      House longhorn beetle

      2B2.     In the geographical areas specified in Table 1, softwood timber for roof construction or fixed in the roof space, including ceiling joists within the void spaces of the roof, should be adequately treated to prevent infestation by the house longhorn beetle (Hylotrupes bajulus L.). Guidance on suitable preservative treatments is given within The Wood Protection Association’s manual ‘Industrial Wood Preservation: Specification and Practice’ (2012), available from 5C Flemming Court, Castleford,West Yorkshire, WF10 5HW

      • 1 Size and proportion of residential buildings of not more than three storeys Diagram 1 Size and proportion of residential buildings of not more than three storeys
      • 2 Size and proportion of non-residential buildings and annexes Diagram 2 Size and proportion of non-residential buildings and annexes
      • 3 Determination of wall thickness Diagram 3 Determination of wall thickness
      • 4 Parapet walls - height Diagram 4 Parapet walls - height
      • 5 Maximum floor area enclosed by structural walls Diagram 5 Maximum floor area enclosed by structural walls
      • 6 Fig 1-2 - Map showing wind speeds in m per s for maximum height of buildings Diagram 6 Fig 1-2 - Map showing wind speeds in m per s for maximum height of buildings
      • 6 Fig 3 - Map showing wind speeds in m per s for maximum height of buildings Diagram 6 Fig 3 - Map showing wind speeds in m per s for maximum height of buildings
      • 7 Max height of buildings Diagram 7 Max height of buildings
      • 8 Measuring storey and wall heights Diagram 8 Measuring storey and wall heights
      • 9 Declared compressive strenght of masonry units Diagram 9 Declared compressive strength of masonry units
      • 10 Maximum span of floors Diagram 10 Maximum span of floors
      • 11 Differences in ground levels Diagram 11 Differences in ground levels
      • 12 Openings in a buttressing wall Diagram 12 Openings in a buttressing wall
      • 13 Buttressing Diagram 13 Buttressing
      • 14 Sizes of openings and recesses Diagram 14 Sizes of openings and recesses
      • 15 Lateral support by floors Diagram 15 Lateral support by floors
      • 16 Lateral support at roof level Diagram 16 Lateral support at roof level
      • 17 Size and location of openings Diagram 17 Size and location of openings
      • 18 Wall thinckness Diagram 18 Wall thinckness
      • 19 Lateral restraint at roof level Diagram 19 Lateral restraint at roof level
      • 20 Proportions for masonty chimneys Diagram 20 Proportions for masonry chimneys
      • 21 Elevation of stepped foundation Diagram 21 Elevation of stepped foundation
      • 22 Piers and chimneys Diagram 22 Piers and chimneys
      • 23 Foundation dimensions Diagram 23 Foundation dimensions
      • 24 Area at risk of collapse in the event of an accident Diagram 24 Area at risk of collapse in the event of an accident
      • Table 1 Areas at risk from house longhorn beetle Table 1 Areas at risk from house longhorn beetle
      • Table 2 Wall types considered in this section Table 2 Wall types considered in this section
      • Table 3 Minimum thickness of certain external walls, compartment Table 3 Minimum thickness of certain external walls, compartment
      • Table 4 Imposed loads Table 4 Imposed loads
      • Table 5 Cavity wall ties Table 5 Cavity wall ties
      • Table 6 Declared compressive strength of masonry units complying with BS EN 771-1 TO -5 [N PER nn SQ] Table 6 Declared compressive strength of masonry units complying with BS EN 771-1 TO -5 (N/mm SQ)
      • Table 7 Normalised compressive strength of masonry units of clay and calcium silicate blocks complying with BS EN 771-1 and 2 [Nn/mm SQ] Table 7 Normalised compressive strength of masonry units of clay and calcium silicate blocks complying with BS EN 771-1 and 2 (N/mm SQ)
      • Table 8 Value of Factor X - see Dia 14 Table 8 Value of Factor 'X' (see Dia 14)
      • Table 9 Lateral support for walls Table 9 Lateral support for walls
      • Table 10 Minimum width of strip footings Table 10 Minimum width of strip footings
      • Table 11 Building consequence Table 11 Building consequence