ATTIX Attic Truss
Design Information
 
 

TIMBER

Machine Gauged

No. 1 Framing Grade Radiata Pine.

OR

Standard Building Grade Douglas Fir.

OR

F5 Machine Stress Graded Radiata Pine.

OR

Equivalent grade of other species refer MiTek New Zealand.

Moisture Content

MiTek New Zealand Ltd recommend a moisture content of 25% or less at time of fabrication.

Truss Design Loads

 

Refer also NZS 3604 and NZS 4203.

Dead Loads

Heavy roof Top Chord 0.80 kPa*

Light roof Top Chord 0.45 kPa*

Bottom chord 0.50 kPa

* Includes ceiling

Live Loads

Top chord 0.25 kPa

Bottom chord 1.50 kPa

Wind Loads

Zones Low, Medium, High, & V High

(as defined in NZS 3604)

Seismic Loads

Seismic zone A, B, & C

Snow Loads

0.5 kPa

Design References

 

NZS 3603

NZS 3604

NZS 4203

TRUSS JOINTS

 

The Gang-Nail Plates are to be pressed into both sides of each joint.

All plate sizes quoted are GN10 plates unless specifically stated.

BRACING

 

Roof bracing to comply with NZS 3604.


Truss Coding 
DESIGN CRITERIA
?Trusses spaced @ 900 crs.
?45?roof pitch only. Attic trusses of other pitches can be referred to a GANG-NAIL Truss Fabricator for
  special design.
?2150mm and 2450mm collar tie heights only.
?3600mm and 4800mm floor spans only.
?Intermediate floor joists @ 450 crs.

FLOOR DETAILS

 

Number of Supports

Floor Span

Floor joist size

2

3600

200 x 50

2

4800

250 x 50

3

3600

150 x 50

3

4800

200 x 50

Definition
Attic Trusses 
to be fixed to top plate with a minimum of 2 wire dogs both ends.
 
Floor Joists -
?Intermediate floor joist size to be the same as the bottom chord size.
?Trimmer joist size to match the Intermediate floor joist size.
?Fix Trimmer and Intermediate floor joists with LUMBERLOK joist hangers,
JH 47x90 and secure top of joists with 1 skew nail.
 
OVERHANG
An overhang may be added to the Attic truss by attaching a supplementary member on to the side as shown in the figure below. The bottom chord may also be chamfered if required, usually to match up with the rest of the roof.
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