Wisconsin Legislature: subch. VII of ch. SPS 321

(d) Floor boards. Where wood boards are used for floor sheathing, the boards shall comply with the minimum thicknesses shown in Table 321.22-E.

(e) Planks. Planks shall be tongue and groove or splined and at least 2 inches, nominal, in thickness. Planks shall terminate over beams unless the joints are end matched. The planks shall be laid so that no continuous line of joints will occur except at points of support. Planks shall be nailed to each beam.

(9) Bridging.

(a) Sawn lumber. Bridging shall be provided for sawn lumber framing at intervals not exceeding 8 feet where the nominal depth to thickness ratio is greater than 4 to 1.

Note: This 4:1 ratio means bridging is required for wood-framed floors having nominal 2X10 or deeper solid-sawn-lumber joists, to provide restraint against rotation or lateral displacement.

(b) Engineered products. Bridging shall be provided for engineered framing products in accordance with the manufacturer’s recommendations.

Note: See s. SPS 321.18 (1) (d) for further requirements relating to floor framing, including for bridging or blocking of floor framing to provide lateral support to the top of foundation walls.

(10) Sill plates. All of the following requirements apply to a sawn-lumber sill plate with uniform loading that is partially extended beyond the load-bearing surface of a foundation wall in order to put the exterior surface of an upper-lying wall flush with or beyond the exterior surface of insulation that is placed on the outside of the foundation wall:

(a) The center of any anchor bolt shall be set back from the side edge of the sill plate by a distance of at least 4 times the diameter of the bolt.

(b) The thickness of the concrete or mortar cover around any anchor bolt shall comply with ACI 318 section 7.7.

Note: Under ACI 318 section 7.7, the minimum cover for a 5/8-inch-diameter or smaller bolt is 1 1/2 inches.

(c) With wood floor joists that are parallel to the foundation wall, the sill plate may not extend beyond the load-bearing surface of the wall by more than one-half of the nominal thickness of the joist that bears on the sill plate.

Note: As used throughout this chapter and in the standards that the chapter incorporates by reference, the shorter side of the cross-sectional area of a wood member is the thickness of the member. The longer side of the cross-sectional area is the depth, when the longer side is vertical; and it is the width when the longer side is horizontal.

Note: Under sub. (6), wood floor joists that are perpendicular to the foundation wall can extend beyond the foundation wall by a distance of up to the depth of the joist.

Note: Subsection (1) (d) requires a full-width sill plate for floor joists over open-core masonry units.

- See PDF for table

- See PDF for table

- See PDF for table

History: Cr. Register, November, 1979, No. 287, eff. 6-1-80; am. (1) and cr. (1m), Register, February, 1985, No. 350, eff. 3-1-85; renum. (8) (c) and (d) to be (8) (d) and (e) and am. (8) (d), renum. Table 21.22-A and D to be Table 21.22 A1 and E, cr. (8) (c), Table 21.22 A2, r. and recr. Tables 21.22 B and C, Register, January, 1989, No. 397, eff. 2-1-89; am. (2), (4), (5), (6) and (9), r. and recr. Table 21.22-A2, Register, March, 1992, No. 435, eff. 4-1-92; am. (5) (b) and cr. (5) (c), Table 21.22-A1, r. Table 21.22-A, Register, November, 1995, No. 479, eff. 12-1-95; r. and recr. (9), Register, January, 1999, No. 517, eff. 2-1-99; r. and recr. (1m), (4), and (5) (b), Register, March, 2001, No. 543, eff. 4-1-01; CR 02-077: am. (5) (b) 1., r. and recr. (6) Register May 2003 No. 569, eff. 8-1-03; CR 08-043: r. and recr. (1), r. (1m), (8) (b) and Table 21.22-C, renum. (3) (intro.), (a) and (b) to be (3) (a), (b) and (c), cr. (3) (d) Register March 2009 No. 639, eff. 4-1-09; correction in (1) (a) 1., (3) (a), (6) (a), (8) (a), (c), (d), Table 321.22-A2 made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672; CR 15-041: cr. (10) Register December 2015 No. 720, eff. 1-1-16; CR 15-043: am. (6) (b) 4. c. Register December 2015 No. 720, eff. 1-1-16.

SPS 321.225 Decks.

(1) Decks attached to dwellings and any detached decks that serve an exit shall comply with the applicable provisions of subchs. II to X of ch. SPS 321, including all of the following:

(a) Excavation requirements under s. SPS 321.14;

(b) Footing requirements under s. SPS 321.15 (2) (f);

(d) Load requirements under s. SPS 321.02;

(e) Stair, handrail and guard requirements of s. SPS 321.04.

(f) Decay protection requirements of s. SPS 321.10.

(2) A deck that complies with the standards in ch. SPS 325 Appendix B, and ch. SPS 325 Appendix C, if applicable, shall be considered as complying with sub. (1).

History: Cr. Register, March, 1992, No. 435, eff. 4-1-92; correction in (1) to (6) made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672; CR 15-043: Renum. to (1) and am., cr. (2) Register December 2015 No. 720, eff. 1-1-16.

Subchapter VII — Walls

SPS 321.23 Wall design.

(1) Live and dead loads. All walls shall support all superimposed vertical dead loads and live loads from floors and roofs.

(2) Horizontal wind load. Walls shall be designed to withstand a horizontal wind pressure of at least 20 pounds per square foot applied to the vertical projection of that portion of the dwelling above grade. No wind load reduction shall be permitted for the shielding effect of other buildings.

History: Cr. Register, November, 1979, No. 287, eff. 6-1-80.

SPS 321.24 Exterior covering.

(1) General. The exterior walls shall be covered with a permanent weather resistant finish.

(2) During construction. During construction, wall cavity insulation may not be installed until a water-resistant covering is in place over the wall cavity and windows, doors and a roof with at least underlayment are installed.

Note: An example of acceptable water-resistant covering for a wall is foam sheathing with permanently taped joints.

(3) Flashing.

(a) Corrosion-resistant flashing shall be installed in the exterior wall to prevent water from entering the wall cavity or coming in contact with the structural framing components.

(b) The flashing shall extend to the surface of the exterior wall finish and prevent water from reentering the exterior wall.

(c)

1. Any joints between 2 pieces of flashing that form a vertical joint shall be lapped a minimum of 6 inches and sealed.

2. Any joints between 2 pieces of flashing that form a horizontal joint shall be lapped a minimum of 2 inches and sealed unless otherwise specified by the flashing manufacturer.

3. Sealants used for flashing shall be exterior grade and shall be compatible with the materials being sealed.

(d) Flashing shall be provided at all of the following locations:

1. At the top of all exterior door and window openings, unless using self-flashing windows that provide at least one inch of flashing around the opening, including the corners.

2. At the intersection of chimneys or other masonry construction with frame walls.

3. Under and at the ends of masonry, wood or metal copings and sills.

4. Continuously above all projecting wood trim.

5. Where porches, decks or stairs attach to a wall or floor assembly of wood frame construction.

6. At wall and roof intersections.

7. At built-in gutters.

8. Along the bottom of door openings that are elevated above-grade.

Note: Flashing placed along the bottom of a door opening that is elevated above-grade can subsequently accommodate adding a deck outside the door.

(e) For a roof that intersects with an upper-lying head wall and rake wall, such as where a dormer is provided, the vertical metal flashing along the rake wall shall extend down the roof at least one-half inch past the vertical flashing on the head wall.

Note: A head wall as addressed in this paragraph intersects a sloping roof at a horizontal line along the top of a roof segment. A rake wall intersects a sloping roof along the side of a roof segment.

(f) For a roof eave that intersects with a sidewall, the end of the roof flashing shall be installed so that it diverts water away from the sidewall and onto the roof or into the gutter.

Note: See s. SPS 321.26 (5) for additional flashing requirements with masonry cavity walls and s. SPS 321.28 (7) for additional flashing requirements with roofing.

Note: See s. SPS 321.26 (8) for further requirements relating to flashing for masonry.

(4) Water-resistive barrier requirements.

(a) General.

1. Exterior walls of wood or metal frame construction shall be provided with a water-resistive barrier from the highest point to the bottom of the permanent weather-resistant covering.

Note: Acceptable water-resistive barrier materials include polymeric-based house wraps and spray-applied water-resistive barriers installed per the manufacturer’s instructions, #15 or greater asphalt-saturated felts that comply with ASTM D 226 for type I felt and extruded foam sheathing with permanently taped joints. Duct tape or similar will not result in a permanently taped joint.

2. Structural products with an integral water-resistive barrier may be approved by the department as a complete assembly.

(b) Material compatibility. The water-resistive barrier material shall be compatible with the other materials in the wall with which it will come into contact.

Note: Spray-applied water-resistive barriers may not be compatible with foam plastic insulation.

1. Polymer-based house wraps shall meet all of the following requirements:

a. A water vapor permeability rating of 5 perms or higher when tested in accordance with ASTM E96.

b. An acceptable water-resistance rating determined in accordance with ASTM D779, AATCC 127 or CCMC 07102.

Note: Asphalt-saturated felt or “tar paper” is not a polymeric-based house wrap.

Note: For more information on the water-resistance tests and their results, see the International Code Council Evaluation Services Acceptance Criteria AC 38.

2. Spray-applied water-resistive barriers shall be approved under the International Code Council Evaluation Services.

Note: For approval criteria, see ICC-ES acceptance criteria AC 212 or successor document.

(d) Application.

1. Horizontal seams in sheet or strip material shall be overlapped such that the upper layer extends over the lower layer at least 2 inches.

2. Vertical seams in sheet or strip materials shall be overlapped at least 6 inches.

3. Any rips, tears or voids shall be patched in accordance with subds. 1. and 2.

(e) Penetrations.

1. Penetrations caused by fasteners of the water-resistive barrier or the weather-resistant exterior covering do not require sealing.

2. Penetrations of 5 square inches or less with an annular space of no more than ½ inch shall be sealed with caulk or similar material.

3. Penetrations of greater than 5 square inches shall be flashed in accordance with sub. (3).

History: Cr. Register, November, 1979, No. 287, eff. 6-1-80; r. and recr. Register, March, 2001, No. 543, eff. 4-1-01; CR 02-077: cr. (3) Register May 2003 No. 569, eff. 8-1-03; CR 08-043: am. (2), renum. (3) (c) to be (3) (d), cr. (3) (c) and (4) Register March 2009 No. 639, eff. 4-1-09; CR 15-041: cr. (3) (e), (f) Register December 2015 No. 720, eff. 1-1-16; CR 15-043: cr. (3) (d) 8. Register December 2015 No. 720, eff. 1-1-16.

SPS 321.25 Wood frame walls. Unless designed through structural analysis, wood frame walls shall comply with the following requirements.

(1) Stud configuration. Wood studs shall comply with the size and spacing requirements indicated in Table 321.25-A. Studs in the exterior walls shall be placed with the wide faces perpendicular to the plane of the wall.

Note: See ch. SPS 325 Appendix A for acceptable nailing schedule.

Note: See s. SPS 321.10 for requirements on treating wood for decay and termite resistance.

(2) Top plates.