Register December 2015 No. 720
APPENDIX C
1. Wood preservatives for ground contact. The following Table lists common pressure-preservative treatments and retention levels, in pounds per cubic foot, for sawn lumber in ground contact – based on the American Wood Protection Association's Book of Standards.
Table C–1
PRESERVATIVE TREATMENTS AND RETENTION LEVELS FOR
1NR = treatment not recommended.
2. Sources of design values. The sources of the design values in Appendix B are as follows:
Table 1 – Minimum footing sizes: The Building Inspectors Association of Southeast Wisconsin, December 2014.
Table 2 – Maximum post heights: Typical Deck Details,
Based on the 2009 International Residential Code, Fairfax County, Virginia, July 2013.
Tables 3A and 3B – Maximum beam spans: Design for Code Acceptance 6, American Wood Council, May 2013.
Table 4 – Maximum joist spans: Design for Code Acceptance 6 (DCA 6), American Wood Council, May 2013; except for the 2x6 values, which are from the Building Inspectors Association of Southeast Wisconsin, December 2014.
Table 5 – Minimum joist-hanger download capacity: Design for Code Acceptance 6, American Wood Council, May 2013; except for the 2x6 values, which are repeated from the 2x8 values.
Table 6 – Ledger-board-fastener spacing: Design for Code Acceptance 6, American Wood Council, May 2013.
Figure 29 – Stringer span length, and Table 7 – Minimum tread sizes:
Design for Code Acceptance 6, American Wood Council, May 2013.
Table C–2 – Maximum joist spans for redwood, western cedars, ponderosa pine, and red pine: Design for Code Acceptance 6, American Wood Council, May 2013; except for the 2x6 values, which are from the Building Inspectors Association of Southeast Wisconsin, December 2014.
Table C–3 – Trimmer joist download capacity: Design for Code Acceptance 6, American Wood Council, May 2013.
3. Joist spans for alternate wood species. The following Table lists maximum joist-span lengths for redwood, western cedars, ponderosa pine, and red pine.
Table C–2
MAXIMUM JOIST-SPAN LENGTH1 FOR REDWOOD,
1Spans are based on 40 psf live load, 10 psf dead load, normal loading duration, wet service conditions and deflections of Ä=L/360 for main span and L/180 for overhang with a 220-lb. point load.
2Design values based on northern species with no incising assumed.
4. Alternate beam and joist spans. The table on the following two pages lists alternate beam and joist spans and corresponding footing sizes from the Southeast Wisconsin Building Inspectors Association that can be used instead of the values in Appendix B
.
- See PDF for table 
Notes:
1. Joist Length (JL) is Joist Span (LJ) plus any cantilever at the beam that is being sized.
2. Incising assumed for refractory species Douglas Fir-Larch.
3. All footing sizes above are base diameters (in inches) and are listed for THREE SOIL CAPACITIES. Soil capacity is based on the requirements of State of Wisconsin SPS 321.15 (3).4
4.
For square footings, insert the diameter (d) into the following formula:√((d/2)2 x p). This number will give you the square dimension and shall be rounded up to the nearest inch.
- See PDF for table
5. Framing around a chimney or bay window. All members at a chimney or bay window must be framed in accordance with Figure C–1. Headers may span a maximum of 6'-0”. Where a chimney or bay window is wider than 6'-0”, one or more 6x6 posts may be added to reduce header spans to less than 6'-0”. In such cases, the post footing must meet the requirements in section 2 of Appendix B. Plan submittal and approval is required for headers with a span length greater than
6'-0”
. Headers must be located no more than 3'-0” from the end of the trimmer joist.
Triple trimmer joists are required on each side of the header if joist spacing is 12” or 16” on center or if the trimmer joist span exceeds 8'-6”
; otherwise, double trimmer joists are permitted. Trimmer joists may bear on the beam and extend past the beam centerline up to LJ/4 as shown in Figures 5 and 7 in Appendix B, or the trimmer joist may attach to the side of the beam with joist hangers as shown in Figure 6 in Appendix B. Joist hangers must each have a minimum download capacity in accordance with Table C–3. Bolts or lag screws used to attach the hanger to the ledger must fully extend through the ledger into the 2-inch nominal lumber band joist (1 1/2“ actual) or the EWP rim board. See Figure 15 in Appendix B for fastener spacing, and edge and end distances. Otherwise a free-standing deck is required.
Figure C–1
DETAIL FOR FRAMING AROUND A CHIMNEY OR BAY WINDOW
Table C–3
6. Attachment of ledger boards to metal-plate-connected wood floor trusses. The research report on the following pages shows acceptable methods for attaching a ledger board to a metal-plate-connected wood-floor-truss system.
Attachment of Residential Deck Ledger to
Metal Plate Connected Wood Truss Floor System
SRR No. 1408-01
Prepared for SBCA
Report Written by:
Jim Vogt, P.E.
October 1, 2014
Table of Contents
Introduction 264
Key Definitions 264
Background 264
Application 265
Installation 265
Findings 272
References and Substantiating Data 272
Introduction:
This research report provides construction details for residential deck ledger attachment to metal plate connected wood truss floor systems. The applicable codes and standards follow the 2009 and 2012 International Building Code (IBC) and the 2009 and 2012 International Residential Code (
IRC). Proper attachment of the deck ledger to the house is critical for ensuring that an “attached” deck is safely and securely supported at this location. This report provides details for attaching a 2” nominal lumber deck ledger to residential floor systems constructed with metal plate connected wood (MPCW) floor trusses.
Key Definitions:
