Framing

Framing is the structural wood components of the wall assembly; in the Effective R Tool, either light framing (studs), or mass timber (CLT).  Lumber used for framing is measured in both nominal and actual sizes.  The nominal size refers to the actual dimension rounded up to the nearest inch and is the most common way to reference lumber size.  The Effective R Tool includes the common framing lumber dimensions of 2x4 inches (38 mm x 89 mm), 2x6 inches (38 mm x 140 mm.), and 2x8 inches (38 mm x 184 mm).  Several measures are available that, when taken together, act to reduce framing lumber (and thermal bridging) and collectively are referred to as advanced framing.

Twinned Studs are typically used for tall wall construction, or midrise buildings.  As the height of the wall increases, or the number of supported floors increase, the studs must be paired together to resist the higher loads.  For an example of how a wall assembly with twinned studs, and its corresponding information, is displayed on the Effective R Tool, please see Wall ID 11762.

Double Stud Walls consists of two parallel wall frames, often with a gap in between and attached to one another to create an extra thick wall with high thermal performance.  The gap between the wall frames can vary in width. The Effective R calculator includes gap spacings of 2.5 inches, 3.5 inches, and 5.5 inches.  The double stud frame allows for more cavity insulation to be installed in the assembly, reducing thermal bridging, and increasing the overall effective R value of the wall.  These walls are considered net zero ready walls.  For an example of how a double stud wall assembly, and its corresponding information, is displayed on the Effective R Tool, please see Wall ID 16266.

Cross-laminated timber or CLT is an engineered wood product that includes alternating layers of flat-laid, dried lumber glued together on their wide faces.  These panels consist of 3, 5, 7, or 9 alternating layers of lumber.  CLT panel construction has a high strength-to-weight ratio and demonstrates advantages in structural, fire, thermal and acoustic performance.  CLT used for wall construction is gaining popularity for tall wood buildings, or tall wall applications.  These panels are typically used for mid-rise and high-rise applications and a professional engineer is often required for these designs.  Read more about CLT here.  For an example of how a cross-laminated timber assembly, and its corresponding information, is displayed on the Effective R Tool, please see Wall ID 11929.

References

Cross-Laminated timber (CLT) - The Canadian Wood Council. (2020, August 30). Retrieved, from https://cwc.ca/how-to-build-with-wood/wood-products/mass-timber/cross-laminated-timber-clt/1

Cross-Laminated timber (CLT). (n.d.). Retrieved April 27, 2021, from https://www.apawood.org/cross-laminated-timber

Lumber - dimension lumber - The Canadian Wood Council. (2019, April 09). Retrieved April 27, 2021, from https://cwc.ca/how-to-build-with-wood/wood-products/lumber/

Ontario Building Code, O Reg. 332/12, s. Table A-30 Sizes for Spruce-Pine-Fir No. 2 Grade Exterior Wall Studs with Brick Veneer