They are a breather type material consisting of bitumen saturated heavyweight kraft paper or fire retardant solvent free laminated two layers reinforced heavyweight kraft paper coated with a water based water repellent.
Metal roofing purlin spacing nz.
When the radius of curvature is close to the minimum the purlin spacing should be reduced to the end span distance for each gauge and profile.
Purlin batten purlin batten fixing type d 3 45kn 2 blue screws or 2 skew nails plus 2 wire dogs for purlin on edge fixing type c 2 4kn purlin batten 1 blue screw 2 nails fixing type b 0 8kn purlin batten fixing type a 0 55kn 1 nail purlin batten note.
Self supporting roofing underlays designed to span between purlins where the purlin spacing is not more than 1200 mm.
1 2 it should be noted that timber purlins for metal roof cladding are minimum 70mm x 45mm h1 2 18 moisture content and that battens used previously for tiles must not be used.
Two nails maybe preferred to prevent batten rolling over with high roof pitches.
The purlin spacings should be limited to the lower of the trafficable limitations and design wind load with the capacity of the structure.
Rafters were birdsmouthed over the top plate and extended beyond the wall framing to create the eaves.
The typical spacing standards for residential and commercial buildings are about 1 to 2 foot.
Where the end purlin spacing is less than 800mm an adjustable end brace with a bolted end cleat is available as twisting of the end cleat is not practical.
This result should be referenced to the wind load span design graphs.
Do all roofing projects require purlins.
We do recommend it however.
The adjustable cleat can be rotated up to 15 degrees from normal to accommodate the change in angle from vertical portal to the roof slope of the rafter.
For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet.
Purlins typically 75 x 50 mm and fixed across the rafters were spaced at 760 900 mm centres depending on the roof cladding.
If a design quotes wind speed in m s ask for a roof plan showing design loads and purlin spacing apply serviceability loads for pierce fastened products ultimate loads for clip fastened profiles.
Fastener patterns on nzs 3604 buildings should be consistent throughout the roof excluding top and bottom rows.
Purlins up to 1200mm spacing must be fixed with a 1 10g 80mm long purlin screw minimum or a pryda purlin strap bs 70.
Ridge boards were 25 mm 1 wide with a depth dependent on the rafter size.
The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.
Purlins are non pressure treated 1 x 4 x 12 lumber that is installed on to the roof in a specific layout pattern and screw pattern.
