ABSTRACT
Herring-bone strutting Figs 7 & 8 are inserted between joists as shown to ensure rigidity. Folding wedges are insereted between the end joists and the wall as shown.
FIG 1
FIG 2
FIG 3
FIG 4
FIG 5 STEEL HANGERS
FIG 6
Joists spanning f from wall to wall are known as bridging joists Fig 7 and are 50mm thick. Where openings occur e.g. for stair wells and around fireplaces, trimmer and trimming joists are used Fig 7. These are 75mm thick, and connected by a tusk tenon Figs 9 & 10. The trimmed joist Fig 7, are housed to the trimmer Fig 12. Alternatively a joist hanger Fig 11 may be used. A rule of thumb for calculating depth of joist is:-" . of span
(in mm)+50=depth in mm e.g. 4m span:- +50=217mm, or say 225mm (standard size)
FIG 7 PLAN 1st FLOOR
FIG 8
FIG 9 TUSK TENON
