Fixings for ordinary rafters are covered in NZS 3604:2011 Timber-framed buildings, as are veranda beams and posts.
Veranda rafters generally span between a ribbon plate attached to the wall of the building and a veranda beam and may overhang the veranda beam by up to 750 mm depending on the size of the rafter. Wind uplift loading under such veranda overhangs is higher than for ordinary rafters so the rafter fixings in NZS 3604:2011 Table 10.1 may not be adequate for some situations.
Use Table 10.1 with these adjustments
Having considered the likely veranda configurations within the overall scope of NZS 3604:2011, BRANZ advice to builders and designers is to use Table 10.1 but with the following adjustments:
- Where the veranda rafter spacing is:
- 1200 mm or more, fixing to the veranda beam should be type F rather than type E as shown in Table 10.1 — an alternative fixing with a capacity of 7.0 kN would also be suitable
- less than 1200 mm, no adjustment is required.
- Rafter fixings to a ribbon plate may be made using Table 10.1 without further adjustment.
- The ribbon plate should be the same size as the rafter and fixed to each stud with 2/14 gauge screws. Screw length should be sufficient to pass through the ribbon plate and cladding and penetrate at least 45 mm into the stud.
