Page 34 - Build 151

solid blocking
300 mm maximum o set
bearer
Figure 2
ooring
timber pile
100 mm minimum
M12 bolt with 50 × 50 ×
3 mm washers connecting pile to bearer
trimming stud
double joists
packers at 600 mm centres maximum
bottom plate
ooring
bearer
300 mm maximum centreline of trimming stud
double joists
Figure 3
Support below doorway under loadbearing wall.
joist
Lateral support o set from brace line (redrawn from NZS 3604:2011 Figure 6.10).
stud
bottom plate
Figure 4 Trimming stud on double joists.
packers at 600 mm centres maximum
Packers between doubled joists under loadbearing walls.
150 mm maximum
Figure 5
solid blocking between oor joists under door studs both sides of doorway
● within 300 mm of sub oor bracing lines (see Figure 2)
● to any joist spanning more than 2.5 m and with a depth of four or more times its thickness. This means any oor joist 190 × 45 mm or greater will require blocking when it has a clear span of more than 2.5 m.
Often, all the joists for suspended oors will be sized to accommodate the largest spans. In
these situations, some of the joists will be larger than required for their spans. If they span less than 2.5 m, no mid-span blocking is required (see Figure 1).
Mid-span lateral support can be provided by: ● herringbonestrutting(clause7.1.2.3)
● solid timber the same depth as the joist –
solid blocking can be o set 50 mm from a centreline at mid-span.
What oor support is required below loadbearing walls?
Where spanning joists run parallel to and support loadbearing walls, double up the loadbearing joists (clause 7.1.3.1). The maximum gap allowed between the two joists is half the width of the wall above.
A packer must be installed into the gap at 600 mm maximum centres. For example, a
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door stud
bottom plate of non- loadbearing wall
ooring
joist