2304.11.2.1 Exterior walls.Exterior walls shall be permitted to be cross-laminated timber not less than 3.5 inches (88 mm) in actual thickness meeting the requirements of Section 2303.1.4.
2304.11.2.2 Interior walls and partitions. Interior walls and partitions shall be of solid wood construction formed by not less than two layers of 1-inch (25 mm) matched boards or laminated construction 3.5 inches (88 mm) in actual thickness, or of 1-hour fire-resistance-rated construction.
2304.11.3.1 Cross-laminated timber floors.Cross-laminated timber shall be not less than 3.5 inches (88 mm) in actual thickness. Cross-laminated timber shall be continuous from support to support and mechanically fastened to one another. Cross-laminated timber shall be permitted to be connected to walls without a shrinkage gap providing swelling or shrinking is considered in the design. Corbelling of masonry walls under the floor shall be permitted to be used.
2304.11.4.1 Cross-laminated timber roofs.Cross-laminated timber roofs shall be not less than 2.5 inches (63 mm) in actual thickness and shall be continuous from support to support and mechanically fastened to one another.
[Statutory Authority: RCW
19.27.031,
19.27.074, and
19.27.540. WSR 23-02-073, 23-12-103, and 23-20-023, § 51-50-2304, filed 1/4/23, 6/7/23, and 9/25/23, effective 3/15/24. Statutory Authority: RCW
19.27.031 and
19.27.074. WSR 20-21-021, § 51-50-2304, filed 10/9/20, effective 11/9/20.]