SPS 321.18   Foundations.
Subchapter VI — Floors
SPS 321.19   Floor design.
SPS 321.20   Concrete floors.
SPS 321.203   Garage floors.
SPS 321.205   Wood floors in contact with the ground.
SPS 321.21   Precast concrete floors.
SPS 321.22   Wood frame floors.
SPS 321.225   Decks.
Subchapter VII — Walls
SPS 321.23   Wall design.
SPS 321.24   Exterior covering.
SPS 321.25   Wood frame walls.
SPS 321.26   Masonry walls.
Subchapter VIII — Roof and Ceilings
SPS 321.27   Roof design and framing.
SPS 321.28   Weather protection for roofs.
Subchapter IX — Fireplace Requirements
SPS 321.29   Masonry fireplaces.
SPS 321.30   Masonry chimneys.
SPS 321.32   Factory-built fireplaces.
Subchapter X — Construction in Floodplains
SPS 321.33   Construction in floodplains.
SPS 321.34   Construction in coastal floodplains.
Subchapter XI — Installation of Manufactured Homes
SPS 321.40   Installation standards.
Ch. SPS 321 Note Note: Chapter Ind 21 was renumbered to be chapter ILHR 21, Register, February, 1985, No. 350, eff. 3-1-85. Chapter ILHR 21 was renumbered chapter Comm 21 under s. 13.93 (2m) (b) 1., Stats., and corrections made under s. 13.93 (2m) (b) 6. and 7., Stats., Register, January, 1999, No. 517. Chapter Comm 21 was reprinted to correct the Table of Contents, Register October 2009 No. 646. Chapter Comm 21 was renumbered chapter SPS 321 under s. 13.92 (4) (b) 1., Stats., Register December 2011 No. 672.
subch. I of ch. SPS 321 Subchapter I — Scope
SPS 321.01 SPS 321.01 Scope. The provisions of this chapter shall apply to the design and construction of all one- and 2-family dwellings.
SPS 321.01 History History: Cr. Register, November, 1979, No. 287, eff. 6-1-80.
subch. II of ch. SPS 321 Subchapter II — Design Criteria
SPS 321.02 SPS 321.02 Loads and materials. Every dwelling shall be designed and constructed in accordance with the requirements of this section.
SPS 321.02(1) (1)Design load. Every dwelling shall be designed and constructed to support the actual dead load, live loads and wind loads acting upon it without exceeding the allowable stresses of the material. The construction of buildings and structures shall result in a system that provides a complete load path capable of transferring all loads from point of origin through the load-resisting elements to the foundation.
SPS 321.02(1)(a) (a) Dead loads. Every dwelling shall be designed and constructed to support the actual weight of all components and materials. Earth-sheltered dwellings shall be designed and constructed to support the actual weight of all soil loads.
SPS 321.02(1)(b) (b) Live loads.
SPS 321.02(1)(b)1.1. `Floors and ceilings.' Floors and ceilings shall be designed and constructed to support the minimum live loads listed in Table 321.02. The design load shall be applied uniformly over the component area. - See PDF for table PDF
SPS 321.02(1)(b)2. 2. `Snow loads.' Roofs shall be designed and constructed to support the minimum snow loads listed on the zone map. The loads shall be assumed to act vertically over the roof area projected upon a horizontal plane.
SPS 321.02(1)(c) (c) Wind loads. Dwellings shall be designed and constructed to withstand either a horizontal and uplift pressure of 20 pounds per square foot acting over the surface area or the wind loads determined in accordance with ASCE 7–05, Minimum Design Loads for Buildings and Other Structures.
SPS 321.02 Note Note: ASCE 7–05 allows for substantial reduction from 20 psf as applied to the surface area.
SPS 321.02(2) (2)Methods of design. All dwellings shall be designed by the method of structural analysis or the method of accepted practice specified in each part of this code.
SPS 321.02 Note Note: See ch. NR 116, rules of the department of natural resources, for special requirements relating to buildings located in flood plain zones. Information regarding the elevation of the regional flood may be obtained from the local zoning official.
SPS 321.02(3) (3)Structural standards.
SPS 321.02(3)(a)(a) General. Design, construction, installation, practice and structural analysis shall conform to the following nationally recognized standards.
SPS 321.02(3)(b) (b) Wood.
SPS 321.02(3)(b)1.1. Except as provided in subd. 1. a. and b., structural lumber, glue-laminated timber, timber pilings and fastenings shall be designed in accordance with the “National Design Specification for Wood Construction" and the “Design Values for Wood Construction," a supplement to the National Design Specification for Wood Construction.
Figure 321.02
SPS 321.02(3)(b)1.a. a. Section The cumulative effects of short-time loads, such as snow, shall be considered in determining duration of load. For snow load, no greater duration of load factor than 1.15 shall be used.
SPS 321.02(3)(b)1.b. b. Section 4.1.7. The provisions of this section shall also apply to reused lumber. Reused lumber shall be considered to have a duration of load factor of 0.90.
SPS 321.02(3)(b)2. 2. Span tables for joists and rafters printed in ch. SPS 325 Appendix A or approved by the department may be used in lieu of designing by structural analysis.
SPS 321.02(3)(b)3. 3. Sawn lumber that is not graded in accordance with the standards under subd. 1., shall use the NDS published allowable design stresses for the lumber species using grade number 3 when used for studs, stringers, rafters or joists and may use grade number 1 when used for beams, posts or timbers.
SPS 321.02(3)(c) (c) Structural steel. The design, fabrication, and erection of structural steel for buildings shall conform to Specification for Structural Steel Buildings and the provisions of the accompanying commentary as adopted under Table 320.24-3.
SPS 321.02(3)(d) (d) Concrete. Plain, reinforced or prestressed concrete construction shall conform to the following standards:
SPS 321.02(3)(d)1. 1. ACI Standard 318, Building Code Requirements for Structural Concrete.
SPS 321.02(3)(d)2. 2. ACI Standard 332, Residential Code Requirements for Structural Concrete.
SPS 321.02 Note Note: Concrete construction in one- and two-family dwellings should meet the standards established in ACI 332. Construction means, materials, or methods not addressed in ACI 332 should meet the standards established in ACI 318.
SPS 321.02(3)(e) (e) Masonry. The design and construction of masonry shall conform to the following standards:
SPS 321.02(3)(e)1. 1. ACI 530, Building Code Requirements for Masonry Structures.
SPS 321.02(3)(e)2. 2. ACI 530.1, Specification for Masonry Structures.
SPS 321.02(3)(f) (f) Engineered structural components. Engineered structural components shall be used in accordance with structural analysis or with load tables supplied by the manufacturer, provided those load tables were developed using structural analysis or load testing.
SPS 321.02(3)(g) (g) Whole logs. Dwellings constructed of whole logs shall conform to ICC 400, Standard on the Design and Construction of Log Structures.
SPS 321.02 Note Note: This standard requires the minimum log diameter to be 8 inches.
SPS 321.02(3)(h) (h) Fasteners.
SPS 321.02(3)(h)1.1. All building components shall be fastened to withstand the dead load, live load, snow load, and wind load.
SPS 321.02(3)(h)2. 2. Fasteners shall comply with the schedule listed in Table 321.02-2.
SPS 321.02 Note Note: Other fastening methods may be allowed if engineered under s. SPS 321.02 (3).
Table 321.02-2
Other interior and exterior panel products and finishes installed per manufacturer requirements.
For engineered connectors, use manufacturer's specified fasteners. - See PDF for table PDF - See PDF for table PDF
1 All nails are smooth-common, box or deformed shank except where otherwise stated.
2 Nail is a general description and may be T-head, modified round head or round head.
3 Staples are 16-gauge wire, unless otherwise noted, and have a minimum 7/16 o.d. crown width.
4 Staples shall be spaced at not more than 10 o.c. at intermediate supports for floors.
5 Apply vertically 4 x 8 or 4 x 9 panels.
SPS 321.02(4) (4)Alternate materials and standards. No part of this code is intended to prohibit or discourage use of alternate, equivalent materials or standards; or the construction of innovative dwellings such as a dwelling built below ground, a geodesic dome, a concrete house, a fiberglass house, or any other nonconventional structure.
SPS 321.02 Note Note: Examples of materials addressed by this subsection include structural insulated panels that are used in accordance with the manufacturer's instructions or structural analysis, and cold-formed steel framing complying with AISI S230 Standard for Cold-Formed Steel Framing — Prescriptive Method for One and Two Family Dwellings.
SPS 321.02 History History: Cr. Register, November, 1979, No. 287, eff. 6-1-80; r. and recr. (3) (a), am. (3) (c) and Table 21.02, cr. (3) (c) 2., Register, February, 1985, No. 350, eff. 3-1-85; cr. (3) (a) 3., am. (3) (b), renum. (3) (e) to be (3) (d), and am., Register, November, 1995, No. 479, eff. 12-1-95; renum. and am. (1) (c) to be (1) (c) 1., cr. (1) (c) 2. and 3., am. (3) (d), Register, January, 1999, No. 517, eff. 2-1-99; r. (3) (a) 3. and cr. (3) (e), Register, March, 2001, No. 543, eff. 4-1-01; correction in (3) (b) made under s. 13.93 (2m) (b) 7., Stats., Register, March, 2001, No. 543; CR 02-077: am. (1) (intro.) and (d) Register May 2003 No. 569, eff. 8-1-03; corrections in (3) (b) and (d) made under s. 13.93 (2m) (b) 7., Stats., Register May 2003 No. 569; CR 08-043: r. (1) (c) 2. and 3., renum. (1) (c) 1., (3) (a) to (e) and (intro.) to be (1) (c), (3) (b) to (f) and (3) (a) and am. (3) (a) and (e), am. (3) (title), cr. (3) (b) 3., (e) 1., 2. and (g), am. (3) (e) Register March 2009 No. 639, eff. 4-1-09; correction in (1) (b) 1., (3) (c) made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672; EmR1403: emerg. am. (1) (c), eff. 4-1-14; CR 14-015: am. (1) (c) Register August 2014 No. 704, eff. 9-1-14; CR 15-041: renum. Table 321.02 to Table 321.02-1 and (1) (d) to (3) (h) 1. and am., am. (3) (c), (d) 1., 2., consol. (3) (g) (intro.) and 2. and renum. to (3) (g) and am., r. (3) (g) 1., cr. (3) (h) 2., Table 321.02-2 renum. from SPS 320 to 325 Appendix and am., (4) renum from SPS 320.02 (5) and am. Register December 2015 No. 720, eff. 1-1-16; correction in (3) (b) 2. under s. 13.92 (4) (b) 7., Stats., Register December 2015 No. 720.
SPS 321.03 SPS 321.03 Exits. Exits, doors and hallways shall be constructed as specified in this section.
SPS 321.03(1) (1)Exits from the first floor.
SPS 321.03(1)(a)(a) Except as allowed under par. (h), every dwelling unit shall be provided with at least 2 exit doors accessible from the first floor.
SPS 321.03(1)(b) (b) At least one of the exits shall discharge to grade and may not go through a garage. This exit may include interior or exterior stairs.
SPS 321.03 Note Note: Under this paragraph, only one of the two exit doors that are addressed in par. (a) is required to exit directly to grade.
SPS 321.03(1)(c) (c) Any exit that does not comply with par. (b) may discharge to an outside balcony that complies with sub. (8).
SPS 321.03(1)(d) (d) Any exit that does not comply with par. (b) may discharge into an attached garage provided the garage has an exit door that discharges to grade. An overhead garage door may not be used as an exit door.
SPS 321.03(1)(e) (e) Except as allowed under pars. (f) and (h), the 2 required exit doors shall be separated by at least the greater of the following distances:
SPS 321.03(1)(e)1. 1. One-third the length of the longest diagonal of the floor in plan view, exclusive of an attached garage.
SPS 321.03(1)(e)2. 2. 20 feet.
Published under s. 35.93, Stats. Updated on the first day of each month. Entire code is always current. The Register date on each page is the date the chapter was last published.