FAQ Category: AWC Standards

What is splicing and how does it affect the structure?

A splice is a means of connecting discontinuous top plate members to transfer the design tension force. For the design assumptions in the WFCM, all top plate joints must be spliced in order to maintain diaphragm chord tension capacity. See WFCM Table 3.21 for top plate splice requirements.

What are the design manuals for wood construction in high wind areas?

The following design standards for wood construction in high wind areas are presently referenced in model building codes such as the IBC (International Building Code) and IRC (International Residential Code): 1. AWC Wood Frame Construction Manual (WFCM) 2015 Edition 2. ICC Standard for Residential Construction in High Wind Regions (ICC-600) The WFCM is an ANSI approved document that provides engineered and prescriptive…

Are there deflection limits for cantilevers?

AWC’s Wood Frame Construction Manual (WFCM) for One- and Two-Family Dwellings prescriptively limits cantilevers based on the following conditions, where L is the length of the simple span, center to center of bearing and d is the depth of the joist: Loadbearing wall, shear wall or non-shear wall <= d Non-loadbearing, shear wall or non-shear wall <=…

How do I calculate a capacity for lumber sheathing or heavy timber decking diaphragms?

AWC’s Special Design Provisions for Wind and Seismic, Table 4.2D contains shear capacities for lumber sheathing attached straight and diagonally. Table 4.3D contains shear wall capacities for straight and diagonal lumber sheathing as well. AWC also publishes Plank and Beam Framing for Residential Buildings (WCD-4) (T14). It shows how this floor and roof framing system, traditionally used in…

What is the maximum shear wall aspect ratio for various wood wall assemblies?

Table 3.17D in the Wood Frame Construction Manual provides maximum shear wall segment aspect ratios for various wood and gypsum assemblies. Also see Special Design Provisions for Wind and Seismic Table 4.3.4. Typically, 3.5:1 is the maximum aspect ratio for design of blocked wood structural panel shear walls. For an 8′ tall shear wall, that would mean 27-1/2″ of…

What resources are available for wood construction in high seismic areas, and why build with wood in earthquake-prone areas?

AWC Wood Frame Construction Manual (WFCM) 2015 Edition is presently referenced in model building codes such as the IBC (International Building Code) and IRC (International Residential Code). The WFCM is an ANSI-approved document that provides engineered and prescriptive requirements for wood frame construction based on dead, live, snow, seismic, and wind loads from ASCE 7-10 Minimum Design Loads for Buildings and Other Structures. AWC Special…