Wis. Admin. Code Department of Safety and Professional Services SPS 321.02

Current through October 28, 2024

Section SPS 321.02 - Loads and materials

Every dwelling shall be designed and constructed in accordance with the requirements of this section.

(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.

(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.

(b)Live loads.

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.

Table 321.02-1

Component	Live Load (pounds per sq. ft.)
Floors ........................	40
Garage floors ..................	50
Exterior balconies, decks, porches ..	40
Ceilings (with storage) ...........	20
Ceilings (without storage) ........	5

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.

(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.

Note: ASCE 7-05 allows for substantial reduction from 20 psf as applied to the surface area.

(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.

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.

(3) STRUCTURAL STANDARDS.

(a)General. Design, construction, installation, practice and structural analysis shall conform to the following nationally recognized standards.

(b)Wood.

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

ZONE MAP FOR ROOF LOADS

Click to view image

a. Section 2.2.5.3. 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.

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.

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.

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.

(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.

(d)Concrete. Plain, reinforced or prestressed concrete construction shall conform to the following standards:

1. ACI Standard 318, Building Code Requirements for Structural Concrete.

2. ACI Standard 332, Residential Code Requirements for Structural Concrete.

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.

(e)Masonry. The design and construction of masonry shall conform to the following standards:

1. ACI 530, Building Code Requirements for Masonry Structures.

2. ACI 530.1, Specification for Masonry Structures.

(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.

(g)Whole logs. Dwellings constructed of whole logs shall conform to ICC 400, Standard on the Design and Construction of Log Structures.

Note: This standard requires the minimum log diameter to be 8 inches.

(h)Fasteners.

1. All building components shall be fastened to withstand the dead load, live load, snow load, and wind load.

2. Fasteners shall comply with the schedule listed in Table 321.02-2.

Note: Other fastening methods may be allowed if engineered under s. SPS 321.02(3).

Table 321.02-2

MINIMUM FASTENER SCHEDULE TABLE

Other interior and exterior panel products and finishes installed per manufacturer requirements.

For engineered connectors, use manufacturer's specified fasteners.

Description of Building Materials/Connection	Number and Type of Fastener^{1 2 3}
Floor Framing
Joist to joist, face nailed over support	3-8d
Joist to sill or girder, toe nail	3-8d
Band or rim joist to joist, end nail	3-16d
Band or rim joist to sill or top plate	2-16d at 16" o.c.
Bridging to joist, toe nail each end	2-8d
Built-up girder and beams, top loaded	10d at 32" o.c. at top and bottom and staggered and two at ends and at each splice
Built-up girder and beams, side-loaded	16d at 16" o.c. at top and bottom and staggered and two at ends and at each splice
Ledger strip to beam, face nail	3-16d each joist
Joist on ledger to beam, toe nail	3-8d
Wall Framing
Sole plate to joist or blocking, face nail	2-16d at 16" o.c.
Top or sole plate to stud, end nail	2-16d
Stud to sole plate, toe nail	3-8d or 2-16d
Doubled studs, face nail	10d at 24" o.c.
Doubled top plates, face nail	10d at 24" o.c.
Doubled top plates, minimum 24-inch offset of end joints, face nail in lapped area	8-16d
Top plates, laps and intersections, face nail	2-10d
Continuous header, two pieces	16d at 16" o.c. along each edge
Continuous header to stud, toe nail	4-8d
1" corner brace to each stud and plate, face nail	2-8d or 2 staples, 13/4"
Built-up corner studs	10d at 24" o.c.
Roof/Ceiling Framing
Ceiling joists to plate, toe nail	3-8d
Ceiling joist, laps over partitions, face nail	3-10d
Ceiling joist to parallel rafters, face nail	3-16d
Rafter to plate, toe nail (maximum 6 rafter span, engineered connector for longer)	2-16d
Roof rafters to ridge, valley or hip rafters, toe nail	4-16d
Roof rafters to ridge, valley or hip rafters, face nail	3-16d
Collar ties to rafters, face nail	3-8d
Boards and planks
1" x 6" subfloor or less to each joist, face nail	2-8d or 2 staples, 13/4"
Wider than 1" x 6 " subfloor toe to each joist, face nail	3-8d or 4 staples 13/4"
2" subfloor to joist or girder, blind and face nail	2-16d
1" x 6" roof or wall sheathing to each bearing, face nail	2-8d or 2 staples, 13/4"
1" x 8" roof or wall sheathing to each bearing, face nail	2-8d or 3 staples, 13/4"
Wider than 1" x 8" roof sheathing to each bearing, face nail	3-8d or 4 staples, 13/4"
2 "planks	2-16d at each bearing

Panel Sheathing

Material	Fastener	Spacing of Fastener
Material	Fastener	Edges	Intermediate Supports
Engineered wood panel for subfloor and roof sheathing and wall corner wind bracing to framing
5/16" to 1/2"	6d common or deformed nail or staple, 11/2"	6"	12" ⁴
5/8" to 3/4"	8d smooth or common, 6d deformed nail, or staple, 14 ga. 13/4"	6"	12" ⁴
7/8" to 1"	8d common or deformed nail	6"	12"
1 1/8" to 11/4"	10d smooth or common, or 8d deformed nail	6"	12"
Combination subfloor/ underlayment to framing
3/4" or less	6d deformed or 8d smooth or common nail	6"	12"
7/8" to 1"	8d smooth, common or deformed nail	6"	12"
1 1/8" to 1 1/4"	10d smooth or common or 8d deformed nail	6"	12"
Wood panel siding to framing
1/2" or less	6d corrosion-resistant siding and casing nails	6"	12"
5/8"	8d corrosion-resistant siding and casing nails	6"	12"
1/2" structural cellulosic fiberboard sheathing	11/2" galvanized roofing nail; 8d common nail; staple 16 ga., 11/2" long	3"	6"
25/32" structural cellulosic fiberboard sheathing	13/4" galvanized roofing nail; 8d common nail; staple 16 ga., 13/4" long	3"	6"
1/2" gypsum sheathing⁵	11/2" galvanized roofing nail; 6d common nail; staple galvanized 11/2" long; 13/4" screws, Type W or	4"	8"
5/8" gypsum sheathing⁵	13/4" galvanized roofing nail; 8d common nail; staple galvanized 1 5/8" long; 1 5/8" screws, Type W or S	7"	7"

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.

(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.

Wis. Admin. Code Department of Safety and Professional Services SPS 321.02

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 15-015: am. (1) (c) Register August 2014 No. 704, eff. 9-1-14.

Amended by, 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, eff.1/1/2016

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.