Sheathing Attachment

The Ontario Building Code (OBC) provides several requirements for OSB wall sheathing acting as lateral bracing for exterior walls and/or a nail-base for certain cladding types. (OBC Div B 9.23.10.2. and OBC Div B 9.23.16.1.). APA recommends that the thickness for wood sheathing used for lateral bracing is 11.1mm (7/16").

OBC provides the following installation requirements for 11.1mm (7/16") OSB sheathing:

A. Minimum 6d (51mm or 2") common nails at 300mm (12") o.c. at intermediate supports connecting 11.1mm (7/16') OSB sheathing to wall structural system. (OBC Div. B 9.23.3.5.)

B. Minimum 6d (51mm or 2") common nails spaced at maximum 150mm (6") o.c. at edge connecting 11.1mm (7/16') OSB sheathing to structure. (OBC Div. B 9.23.3.5.)

C. End joints of sheathing must be staggered if intended to be used as bracing. (OBC Div. B 9.23.16.4.)

D. Sheathing must have a minimum gap of 2mm (1/8") between panels. (OBC Div. B 9.23.16.5.)

APA recommendations align with NBC and OBC requirements under normal circumstances.

What is SB-12?

The 2012 Ontario Building Code’s Supplementary Standard SB-12 sets out the energy efficiency requirements for Part 9 structures. Chapter 3 of SB-12 provides methods for achieving energy efficiency compliance after December 31, 2016. Compliance can be achieved by:

1. Following a prescriptive compliance package,
2. Modelling the energy consumption to demonstrate a level of performance, or
3. Demonstrating another compliance method such as qualification under Energy Star for New Homes.

The prescriptive packages of SB-12 provide minimum thermal values for above-grade walls. The minimum thermal resistance value targets are provided as both nominal and effective RSI/R-values. Users have the ability of meeting the nominal or effective RSI/R-value targets provided for each prescriptive package.

Advanced Framing

The National Building Code defines advanced framing:
‘Advanced framing’ refers to a suite of framing techniques and details designed to optimize material use and thereby increase the energy efficiency of a building. By eliminating redundant framing components and replacing with more insulation, the effective RSI/R-value of a wall assembly can be increased. This not only leads to a potential savings in material, labour and insulation materials but it also provides more options for builders and designers when it comes to energy code compliance. The 2020 National Building Code of Canada defines advanced framing as “constructions with insulated lintels or framing designed without lintels, corners with one or two studs, no cripple or jack studs, and double top plates”. Table A-9.36.2.4.(1)-A provides framing and cavity percentages for both typically framed wood walls as well as those framed using advanced framing techniques and details.

Explore SB-12 Compliant Walls

The 2012 Ontario Building Code includes Supplementary Standard SB-12 which provides, among other targets, the required insulation values for building assembles, including above-grade walls. Prescriptive tables are included in SB-12 for electric heating appliances and for gas or oil heating appliances. The gas or oil appliances involve two tables: one for appliances with efficiencies of at least 92%, and the other for appliances with efficiencies between 84% and 92%. In total three tables are included in SB-12 which provide the minimum thermal resistance for wall assemblies in Ontario’s two climatic zones. Zone 1 includes all municipalities with less than 5000 heating degree-days while Zone 2 includes all areas with 5000 heating degree-days or more.

By clicking the desired ► symbol in the tables below, users will find walls that meet the minimum nominal requirement for each respective compliance package along with high-performance compliant walls that meet the minimum effective RSI/R-value targets instead.