Hatch Detail Hatch and chimney openings: Whenever possible hatch openings should be accommodated within the trussed rafter design spacing. When this is not possible the method shown on the left should be used.
D max is equal to twice the design truss spacing less the opening width Jack Rafter 25mm deeper than trussed rafter and birdmouthed over wallplate
Chimney Detail All timbers must be at least 50mm clear of the chimney brickwork
Jack Ceiling Joist nailed to side of jack rafter, size to match bottom chord of trussed rafter
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