Advance Framing

We've received a few calls recently asking about advance framing, and there seemed to be some confusion within the office as to what that means for us.

I've downloaded the APA guide and placed it on the server.  You can find it on the server at
G:\Codes and Publications\APA\Advanced Framing Construction Guide M400.PDF

From a review of advance framing techniques online, it appears that the term refers to a group of techniques that, when taken together, result in using less lumber for a home, reducing energy inefficiencies and building costs at the same time.

There are quite a few parts of the Advance Framing System that are relevant to us.  Please note that individual contractors and clients may want to use some, all or none of these options.

1. Stud Spacing:  Wall stud spacing is increased to 24" o.c. typical.  For a single family dwelling, this is rarely a serious concern for typical 8' plate heights; even HF studs can support sufficient load to carry two stories of load with typical spans.
2. Wall Corners:  Wall corners are built with fewer studs; two studs with either drywall clips or blocking to support the edge of the drywall at the side without a full stud.  The largest concern I see here is that it makes locating tiedowns slightly more difficult (taller tiedowns must compete with the blocking, or be moved to one side) and that it leaves the corners weaker for vertical load.  Additional care must be taken when providing beam support at corners; we can't assume that either direction will be braced unless we detail the connection.  This also reduces the usefulness of shared holdown corners.
3. Blocking:  One of the goals is to reduce thermal bridging; blocking should be specified as vertical, with one face aligned with either the drywall or the exterior sheathing.
4. Top Plate:  Per 2012 IRC R602.3.2, single top plates may be used when rafters or joists are centered over the stud with a tolerance of 1" or less.  Combined with item #1, that means that all framing on every floor must be lined up at 24" o.c..  In addition, the top plate must be spliced to serve as a proper chord for the shear walls.  
5. Wood Structural Box Panels:  Window and door headers may be designed as box headers instead of solid wood.  Refer to 2012 IRC Section 602.7.2, Table 602.7.2 and Figure 602.7.2 for specifications, sketches and span tables for conventional construction.
6. Jack Stud Reduction:  This one isn't entirely in our field.  Depending on where the smaller (4'-0") openings in the walls are placed, the jack studs may be eliminated if a header clip or similar mechanical connection is used (re: Table 3.23D of the 2012 WFCM).  In addition, fewer studs should be specified at openings in general; again, refer to Table 3.23D.
7. Truss Heel:  Expect to see more buildings with larger truss heels.
8. Diaphragm to Diaphragm connection:  Metal strapping and connectors for floor to floor load transfer are discouraged.  I don't see an alternative for uplift at shear wall corners, but the APA has a reference (SR-101, also in G:\Codes and Publications\APA\) that recommends placing the sheathing such that it splices over the rim joist (or, in the case of trusses, at the raised heel) or at blocking at mid-height.  Since one of the goals is to eliminate lumber used, I think that using 10' sheets and splicing at the rim joist is the better solution.  If 8' sheets are used, either option will add blocking to the wall.

The only one of these items I see a significant issue with is item #4, the single top plate.  I see too many issues in the field to be happy with the idea of requiring that contractors provide 1" tolerance for framing members.  In addition, I see quite a few concerns when it comes to top plate slices.  I recommend that we discuss that one in depth as a group.  The others are either (un)common sense or less problematic.