jdgengineer
Structural
- Dec 1, 2011
- 748
When you are using advanced framing techniques (2x6 exterior studs @ 24" oc) what exterior sheathing do you specify when you have stucco or other relatively brittle finishes? Our office standard is to use 15/32" exterior sheathing (for typical 16" of studs). This sheathing is typically installed vertically (strength axis parallel to studs).
Per SDPWS Table 3.2.1 at 24" oc spacing 15/32" (4 or 5 ply) panels are capable of spanning 24" with 40 PSF nominal capacity when installed vertically. This would translate to 25 PSF allowable wind pressure. In low wind areas (110 mph per ASCE 7-10) this would calculate out without issue. However, APA put out a document in 1996 (Installation of Stucco Exterior Finish Over Wood Structural Panel Sheathing). Here they recommend 19/32" plywood or OSB where panels are to be installed vertically. I see no mention of this requirement in their Advanced Framing Construction Guide published in 2014. I sense we will get some push back on the 5/8" plywood, but want to make sure the stucco is properly supported.
What do you all use in these situations? We could specify that the panels be installed horizontally but I suspect this would be installed incorrectly often. Additionally, if you are adding blocking at the panels joints it defeats the purpose a bit of using 24" oc stud spacing. With stucco finish, I would think you would want blocking or framing clips to support the unsupported edges to avoid cracks.
Per SDPWS Table 3.2.1 at 24" oc spacing 15/32" (4 or 5 ply) panels are capable of spanning 24" with 40 PSF nominal capacity when installed vertically. This would translate to 25 PSF allowable wind pressure. In low wind areas (110 mph per ASCE 7-10) this would calculate out without issue. However, APA put out a document in 1996 (Installation of Stucco Exterior Finish Over Wood Structural Panel Sheathing). Here they recommend 19/32" plywood or OSB where panels are to be installed vertically. I see no mention of this requirement in their Advanced Framing Construction Guide published in 2014. I sense we will get some push back on the 5/8" plywood, but want to make sure the stucco is properly supported.
What do you all use in these situations? We could specify that the panels be installed horizontally but I suspect this would be installed incorrectly often. Additionally, if you are adding blocking at the panels joints it defeats the purpose a bit of using 24" oc stud spacing. With stucco finish, I would think you would want blocking or framing clips to support the unsupported edges to avoid cracks.
