Boundary Joists and Rimboards
All rimboards and boundary joists are available as Engineered Wood Products to ensure timber shrinkage rates are similar for all members to avoid uneven loadings.
Lumberworx adopts NZS3604:2011 for parallel boundary joists under load-bearing walls in its floor designs. A double 45mm LVL joist is specified under all load-bearing external walls and a single 45mm joist under non load-bearing boundaries (such as at stairwells).
This standard avoids asymmetric loadings onto perimeter I-Beams after wind or seismic action, and means the builder does not have to fit web stiffeners to I-Beams after upper floor frames have been put in place.
The same standard is adopted for rimboards
to the heads of joists and 25mm minimum thickness is recommended.
Web Stiffeners & Packers
Lumberworx can supply 25 and 39mm blocks for its 65 and 90mm series I-Beams.
These can be used as:
- web stiffeners under concentrated loads
- packers to facilitate fixing of other members to Lumberworx I-Beams
OR these can be field cut. Web stiffeners to support the I-Beam web under concentrated loads or for use with partial joist hangers can be a minimum of 21mm thickness.
Lumberworx can supply hardware for fixing of I-Beam and LVL joists and rafters.
It is recommended that an engineer be consulted to ensure fixings are specified for the applicable conditions, alternatively consult the manufacturers’ literature.