BCAB #1417 - Sheathing Thickness for Stucco Lath, Sentence 220.127.116.11.(2)
July 17, 1996
Re: Sheathing Thickness for Stucco Lath, Sentence 18.104.22.168.(2)
This appeal concerns stucco application on a single family dwelling.
Reason for Appeal
Sentence 22.214.171.124.(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 126.96.36.199.(1) requires stucco lath to be fastened in conformance with Subsection 9.27.5. Sentence 188.8.131.52.(2) states that "...stucco lath...may be attached to sheathing only where the sheathing consists of not less than...12.5 mm...strandboard."
The appellant has installed 3/8" (9.5 mm) strandboard and contends that Sentence 184.108.40.206.(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 220.127.116.11.(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 18.104.22.168.(2) the sheathing only has to conform to Subsection 9.23.16. Sentence 22.214.171.124.(2) only applies where the sheathing is required as a base for fasteners
George R. Humphrey, Chair