BCAB #1417 - Sheathing Thickness for Stucco Lath, Sentence 9.27.5.1.(2)

July 17, 1996

BCAB #1417

Re: Sheathing Thickness for Stucco Lath, Sentence 9.27.5.1.(2)

Project Description

This appeal concerns stucco application on a single family dwelling.

Reason for Appeal

Sentence 9.28.1.1.(2) requires sheathing beneath stucco to comply with Subsection 9.23.16. Article 9.23.16. 2. requires minimum 6.0 mm strandboard on studs at 400 mm o.c. and 7.5 mm strandboard on studs at 600 mm o.c. Sentence 9.28.4.6.(1) requires stucco lath to be fastened in conformance with Subsection 9.27.5. Sentence 9.27.5.1.(2) states that "...stucco lath...may be attached to sheathing only where the sheathing consists of not less than...12.5 mm...strandboard."

Appellant's Position

The appellant has installed 3/8" (9.5 mm) strandboard and contends that Sentence 9.27.5.1.(2) requiring 1/2" (12.5 mm) strandboard applies where stucco lath is attached to the sheathing only. The stucco lath in this case is fastened to the framing which is at 400 mm o.c. for the walls and 600 mm o.c. for the gable ends.

Building Official's Position

The building official maintains that Sentence 9.27.5.1.(2) requires 12.5 mm (1/2") strandboard sheathing behind stucco lath to provide proper support and backing. In the event of impact it will prevent the stucco from cracking.

Appeal Board Decision #1417

It is the determination of the Board that providing the lath conforms with Table 9.28.4.A. and is attached with a fastener pattern conforming to Sentence 9.28.4.6.(2) the sheathing only has to conform to Subsection 9.23.16. Sentence 9.27.5.1.(2) only applies where the sheathing is required as a base for fasteners

George R. Humphrey, Chair