SPECIFICATIONS (job – built wood ladders)
1. Ladder Construction
- Rails - 2" x 4" spaced
16" to 20" apart, to
maximum length of 24'
- Rungs - straight grained
1" x 4" or 2" x 4"
spaced 12" on centre
- Filler blocks - 1" x 2"
or 2" x 2" secured with
3 nails
- Nails - use 2½" nails
for 1" thick rungs and
filler blocks and 3" nails for 2" thick rungs and filler blocks
e. Safety strapping - the wire or banding must be secured to each rung and
filler block
2. Knots in rungs
- maximum of 2 tight and sound
knots per rung, minimum of 6"
apart and more than 1" away
from edge of the rung
- maximum knot diameter -¾"
- spiked knots - not permitted in
rungs
