Building
A Wooden Ladder
1.All ladder components should be made of construction grade lumber, #1
structural grade, or better. See Figure 1 below.
2.Side rails for ladders up to 4.9 metres (16 feet) should be 51
millimetres by 102 mm (2 inches by 4 inches nominal) and side rails for
ladders between 4.9 m (16 feet) and 7.3 m (24 feet) should be 51 mm by
152 mm (2 inches by 6 inches nominal). The dimensions of a 2 inch by 4
inch stud are 1 1/2 inches by 3 1/2 inches. A 2 by 4 inch stud is not
deep or wide enough for a side rail. A larger piece of lumber must be
cut down to two inches of depth and 4 inches of width.
3.Cleats for ladders up to 4.9 metres (16 feet) should be 25 mm by 76
mm (1 inches by 3 inches nominal) and side rails for
ladders between 4.9 m (16 feet) and 7.3 m (24 feet) should be 25 mm by
102 mm (1 inches by 4 inches nominal).
4.Do not notch the side rails to receive the cleats. Nail the cleats to
the narrow edge of the rails. Close fitting fillers should be used to
fill the spaces between the cleats. The fillers should have the same
thickness as the cleats.
5.The distance between side rails should be between 381 mm and 508 mm
(15 inches and 20 inches).
6.Cleat spacing should be at 305 mm (12 inch centres).
7.Two 57 mm (2 1/4 inch) nails should be used to nail each end of
cleats made of 25 mm by 76 mm (1 inch by 3 inch nominal) wood.
8.Three 57 mm (2 1/4 inch) nails should be used to nail each end of
cleats made of 25 mm by 102 mm (1 inch by 4 inch nominal) wood.
9.Make all of the side rails, cleats and fillers before the ladder is
assembled. Nail a filler at the bottom of each side rail first. Nail
the ends of a cleat to each side rail above and in contact with each
filler. Nail the next two fillers and cleat and so on. The ladder will
be complete when a filler is nailed at the top of each side rail. The
ladder begins and ends with a filler. A ladder made with ten cleats
will be ten feet plus the length of a filler in length. One foot (305
mm) equals the sum of the length of a filler and the width of a cleat.
A ten cleat ladder will also have two rails and twenty-two fillers. A
ten foot ladder is actually nine feet plus the length of a
filler
in length or ten feet minus the width of a cleat.