Laminating Details for Double Trusses
Laminating Methods
It is necessary that double trusses are nailed together prior to loading the roof.
In Chords: two (2) rows (staggered) of 3.05mm diameter nails at maximum 450 centres from one side, or use 1/Green Tip screw.
In Webs: one (1) row of 3.05mm diameter nails at maximum 450 centres from one side. A minimum of two nails per web is required or use 1/Green Tip Screw at 600 centres.
Nail Lengths:
65mm long for up to 38mm thick laminates.
75mm long for up to 50mm thick laminates.
Special truss design fixings may be specified in excess of this.
Figure C1-03-02-01
Figure C1-03-02-02
Laminating Details for Triple Trusses
Laminating Methods
It is necessary that triple trusses are nailed together prior to loading the roof.
In Chords: Nail as for double truss from each side, and also use 1/M12 bolt at joints or 2/Green Tip Screws from each side at every web junction through the top chord, plus at the heel joint through the top chord.
If bolted brackets are used on the bottom chord at 1200mm centres or less, then these bolts are sufficient for bottom chord.
In Webs: one (1) row of 3.05mm diameter nails at maximum 450 centres from each side. A minimum of two nails per web is required or use 1/Green Tip Screw at 600 centres.
Screw Lengths:
65mm long Green Tip Screws for up to 38mm thick laminates.
100mm long Black Tip Screws for up to 50mm thick laminates.
Special truss design fixings may be specified in excess of this.
Figure C1-03-03-01
Figure C1-03-03-02
Figure C1-03-03-03
