Village of Fox Point, WI
Milwaukee County
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Table of Contents
Table of Contents
Unless designed through structural analysis, wood frame construction shall be of either balloon, post and beam, platform or other approved system and shall comply with the following requirements:
A. 
Grades and sizes. All lumber used for framing shall be sound, free from rot and large or loose knots and damaging diagonal or spiral grain and shall be of the structural grade corresponding to the stresses used in design. All lumber sizes herein specified are nominal sizes and apply to surfaced (S4S) lumber having dimensions which conform to the American Softwood Lumber Standard Sizes, PS 20-70. All structural wood framing shall be a minimum of two inches in nominal thickness except for approved composite or built-up integrated units.
B. 
Stress and loading requirements.
(1) 
Allowable stresses. Lumber used in frame construction shall be in accordance with such values as established by the National Design Specification for Wood Construction.
(2) 
Live loads. One- and two-family residential construction shall be designed and constructed to support the following live loads without exceeding the allowable stresses:
(a) 
Floors: 40 pounds per square foot.
(b) 
Garage floors: 60 pounds per square foot.
(c) 
Ceilings (with storage): 20 pounds per square foot.
(d) 
Ceilings (without storage): 10 pounds per square foot.
(e) 
Roofs (slope 3 in 12 or less): 40 pounds per square foot.
(f) 
Roofs (slope over 3 in 12): 30 pounds per square feet.
C. 
Wood structural design requirements.
(1) 
Tabulated information. As contained in the "Span Tables for Joists and Rafters, American Softwood Lumber Sizes, PS 20-70" and in the supplement "Design Values for Joists and Rafters," is based on the National Design Specification for Wood Construction and is an acceptable authority under the provisions of this code. Both publications may be obtained from the National Forest Products Association, 1619 Massachusetts Avenue NW, Washington, D.C. 20036.
(2) 
Plywood. As used for siding, roof and wall sheathing, subflooring, diaphragm, built-up members and other such structural application, shall conform to the performance standards for its type as contained in "U.S. Products Standards PS-1-74 for Softwood Plywood/Construction and Industrial." Specifications for the use of plywood products published by the American Plywood Association and based on the requirements of PS-1-74 are acceptable design authority under the provisions of this chapter. Plywood panels identified under the grade trademark of the APA are approved when used in accord with APA recommended specifications for the intended use. PS-1-74 and APA specifications may be obtained from the American Plywood Association, 1119 A Street, Tacoma, Washington 98401.
D. 
Girders and beams.
(1) 
Girders and beams for uniformly loaded one- or two-story buildings may be selected from the table below:
Minimum Size Girder or Beam of A-36 Steel
Span C to C of Bearing
(feet)
Width of Floor Tributary to Beam
(feet)
One-Story Building*
Two-Story Building**
8
10 to 12
W 6 x 12
W 8 x 13
8
12 to 18
W 6 x 13
W 8 x 17
9
10 to 12
W 8 x 10
W 8 x 15
9
12 to 14
W 8 x 13
W 8 x 17
9
14 to 18
W 8 x 15
W 8 x 20
10
10 to 12
W 8 x 10
W 8 x 15
10
12 to 14
W 8 x 13
W 8 x 20
10
14 to 18
W 8 x 17
W 10 x 21
11
10 to 12
W 8 x 13
W 10 x 17
11
12 to 14
W 8 x 17
W 10 x 21
11
14 to 18
W 8 x 20
W 10 x 25
12
10 to 12
W 10 x 11.5
W 10 x 21
12
12 to 14
W 10 x 17
W 12 x 25
12
14 to 18
W 10 x 17
W 12 x 27
NOTES:
*
One-story building: Assumes combined live and dead loads of 100 psf imposed on the supported first-floor joists - no roof loading.
**
Two-story building: Assumes combined live and dead loads for both floor levels of 170 psf imposed on the supported first-floor joists - no roof loading.
(2) 
Extreme load conditions. Where concentrated loads or uniform loads exceeding the table are supported, calculations shall be submitted to prove acceptable performance. Calculations shall be required for girders or beams of reinforced concrete, solid wood or built-up wood members.
(3) 
Wood girder and beam joints. Joints of abutting wood beam or girder members shall be made over column or pier supports. Where wood girders and beams frame into concrete or masonry, a minimum of 1/2 inch air space shall be provided at ends and sides unless treated wood is used. Wood shims are not acceptable under wood girders or beams.
E. 
General framing requirements.
(1) 
Structural strength impaired. Structural framing members shall not be spliced between bearing points. Where structural strength is impaired by cutting, drilling or inherent defects, such members shall be reinforced in a manner acceptable to the Building Inspector.
(2) 
Cutting and notching. Bored holes in joists, girders or beams shall be no greater than 2 1/2 inches in diameter and shall be located in the end 1/4 of span and shall not be more than 1/4 of the joist depth. The top or bottom edges of joists may be notched in the outer 1/4 of the length not to exceed 1/6 of the joist depth. Notching the top or bottom edge of joists will not be permitted in the middle half of the length of any joist. In studs of walls or partitions, holes and notches made to receive piping or duct work, or for other fabrication purposes, shall be cut not more than 1/2 the depth of the stud. Not more than two successive studs shall be so cut or bored unless they are doubled or otherwise reinforced as required by the Building Inspector.
(3) 
Connections and fastenings. All structural members shall be connected and fastened at their junctions with connectors, bolts, lag screws, spikes, nails, straps or other approved devices or by approved gluing and in accordance with the recommended nailing schedule in Table No. 4.[1]
[1]
Editor's Note: Table No. 4 is included as an attachment to this chapter.
(4) 
Bridging. In all ceilings, floors, attic and flat roof joist framing, there shall be not less than one line of bridging for each eight feet of span and the bridging shall not be less than one-inch-by-three-inch lumber double-nailed at each end, or equivalent metal lateral bracing of equal rigidity secured at the intersections. A line of bridging shall also be required at supports where adequate lateral stiffness is not otherwise provided. Solid bridging is also acceptable. Where two-by-six-inch ceiling joists are used, a minimum two-by-four-inch stay-lathe may be substituted for required bridging. Such stay-lathe shall be spiked securely at each joist and at each end to either stud or rafter.
(5) 
Fire stopping. Fire stopping shall be provided at all intersections of interior and exterior walls with floors, ceilings and roof in such a manner as to effectively cut off communication by fire through hollow concealed spaces and prevent both vertical and horizontal drafts. Furred walls shall have fire stops above and below the junction of any floor construction with the walls.
(6) 
Fire-stopping materials. Wood fire stops shall be of lumber not less than two inches in nominal thickness or 3/4 inch thick plywood and not less in width than the enclosed space within the partition except as provided for chimneys. Space between the chimney and wood framing shall be solidly filled with noncombustible materials at floor or ceiling levels. Fire stops may also be of gypsum board, mineral wool or other approved noncombustible materials securely fastened in place.
F. 
Floor and ceiling framing.
(1) 
Joist, spans and sizing. For ordinary conditions of use and live loads, the spans of joists shall be limited by the following tables:
(a) 
Table (J-1) Living Areas.
(b) 
Table (J-4) Limited Attic Storage.
(c) 
Table (J-6) No Attic Storage.
(2) 
Truss joist design. Truss joists shall be designed through structural analysis and such design shall bear the seal of an architect or engineer registered in the State of Wisconsin.
(3) 
Bearing and anchorage. Floor joists framing into walls or girders shall be anchored, tied or nailed to secure continuity. The ends of each joist or truss shall have not less than one-and-one-half-inch length of bearing on wood or metal nor less than three-inch length on hollow or solid masonry units. The ends of beams or girders shall have not less than four-inch length of bearing. Beams or joists framing from opposite sides shall either lap not less than six inches nor more than 12 inches and be securely bolted or spiked together. When framing end to end, all joists, beams and girders shall be secured together by approved metal ties, strap or scabs.
(4) 
Multiple joists. Floor joists under terrazzo, tile, bathtubs or other unusual loading conditions shall be doubled or otherwise reinforced to support the load. Floor joists under partitions running parallel thereto shall be doubled or formed of built-up sections or may be replaced by a solid section of adequate strength to support the loads.
(5) 
Joist headers and trimmers. All joist headers more than four feet in length and their trimmers shall be doubled. All tail beams or joists which are more than six feet in length shall be hung in approved joist or beam hangers or shall be fastened by approved metal connectors. All double trimmer joists shall be spiked together. A minimum two-inch-by-two-inch ledger strip may be used in lieu of hangers or connectors.
(6) 
Hung ceiling. Ceiling joists, when parallel to roof joists, shall be two inches by four inches at the same spacing as the joists above and hung by not less than one-inch-by-four-inch hangers spaced at not more than six feet. Ceiling joists, when at right angles to roof joists, shall be two inches by four inches spaced 16 inches on center and hung by not less than two-inch-by-two-inch hangers spaced at not more than six feet.
G. 
Wall framing.
(1) 
Design loads. Walls shall be designed to support all superimposed loads from floors and roof. Exterior walls shall be designed to withstand a horizontal wind pressure of at least 20 pounds per square foot.
(2) 
Stud size and spacing. For ordinary conditions of use, wood studs shall comply with the size and spacing requirements of the following table:
Maximum Spacing and Height of Studs
Spacing
(inches)
Size
Grade
Maximum Height
(feet)
Supporting Roof and Ceiling Only
Supporting 1 Floor, Roof and Ceiling
Supporting 2 Floors, Roof and Ceiling
Interior and Non-Load Bearing
2 x 3
Standard and better
8
16
N/P
N/P
24
2 x 4 or larger
Utility
8
24
16
12
24
2 x 4
Standard and better
12
24
24
12
24
2 x 6 or larger
No. 3 and better
18
24
24
16
24
N/P = Not Permitted
NOTE: A three-story frame house with walls constructed of two-by-four studs would require a twelve-inch stud spacing on the lowest level, a sixteen-inch stud spacing on the intermediate level and a twenty-four-inch stud spacing on the upper level.
(3) 
Plates and ribbon boards. All walls shall be provided with a single bottom plate and double top plate. Top plates shall be lapped no closer than 32 inches at all intersecting walls and corners. Plates shall be of the same width as the supporting stud and each not less than two inches thick. Plates shall be spliced above studs. Ribbon boards, which support floor or roof joists, shall not be less than one inch by four inches in size and shall be notched into the studs and nailed thereto as required by the nailing schedule.
(4) 
Stud walls. All walls and partitions shall be constructed using studs of continuous length. Nonbearing partitions only may be constructed with the smaller dimension perpendicular to the wall. Studs cut so as to impair their structural strength shall be reinforced as required by the Building Inspector.
(5) 
Wood posts. The load-bearing value of isolated post or studs shall be verified by calculations submitted to prove acceptable performance. All wood posts used in basements or cellars shall have concrete bases which extend not less than three inches above the finished floor and bear directly on the post footing. In cellars or basements, all wall plates or stair stringers shall rest on top of the finished concrete floor.
(6) 
Bracing. Corner posts shall be the equivalent of not less than three pieces of two-inch by four-inch studs braced with not less than one piece of one-inch by four-inch diagonal let into the wall framing. Diagonal bracing shall be fastened at each bearing point with the studs and with the sole and top wall plates. Diagonal bracing may be omitted when approved plywood sheathing is installed or when one-inch board sheathing is placed diagonally. Equivalent metal bracing products may be used when approved by the Building Inspector.
(7) 
Framing of opening. All windows and door openings shall have double studs for the full height of the door openings at jambs, with double headers or truss construction over the opening, or by other approved methods or connection devices to support the superimposed loads. The jamb studs shall be a minimum of two-inch-by-four-inch studs double with the inner stud extending in one piece from header to bearing securely spiked to the outer stud.
(8) 
Headers. All headers over openings in bearing walls or partitions shall consist of double joists on edge not less than herein specified or truss construction bearing on jack studs or other approved construction affording adequate strength.
(a) 
Wood headers for one- and two-story buildings may be selected from the table below:
Wood Headers for Bearing Walls
Span
Minimum Header Size
Less than 4' 0"
Two (2" x 4")
4' 0" to 5' 6"
Two (2" x 6")
5' 6" to 7' 0"
Two (2" x 8")
7' 0" to 8' 6"
Two (2" x 10")
8' 6" to 10' 0"
Two (2" x 12")
(b) 
Where headers support greater or lesser uniform or concentrated loads, or are subject to other unusual loading conditions, calculations shall be submitted to prove acceptable performance.
H. 
Roof framing.
(1) 
Rafter spans and sizing. For ordinary conditions of use and live loads, the spans shall be limited by the following tables:
(a) 
Table R-9 (slope 3 in 12 or less).
(b) 
Table R-11 (slope over 3 in 12).
(2) 
Rafter support and collar ties. Roof rafters shall be vertically supported with two-by-fours spaced not more than 32 inches on center, at the ridge when the slope of the roof is less than four inches per foot. When the slope is more than four inches per foot, roof rafters shall be vertically supported at the ridge or shall be adequately trussed or tied together with not less than one-inch-by-six-inch collar beams spaced not more than 32 inches on center, located a minimum of 1/3 the rafter length below the ridge, and each rafter shall be fastened to the wall plate or special plate provided. Roof rafters shall be framed opposite each other at the ridge.
(3) 
Collar beams. When collar beams are above the lower third of the rafters and ties are not provided at the plate line, provision shall be made for tying the lower end of the ceiling or wall construction.
(4) 
Ridge boards. The depth of ridge boards shall not be less than the cut end of the rafter.
(5) 
Double rafters. Dormer windows and other openings in roofs shall be framed with double rafters and headers. Valley rafters on spans over 12 feet, measured horizontally, shall be doubled.
(6) 
Valley and hip rafter size. The depth of valley or hip rafters shall not be less than the cut end of the rafter. The thickness of valley or hip rafters shall not be less than two inches.
(7) 
Dormers or gables. If over six feet in width, the valley rafters shall run through to the ridge of the main roof. Where the ridge of the dormer or gable is below the ridge of the main roof, one valley rafter shall run through to the ridge of the main roof.
(8) 
Factory constructed trusses. Factory constructed trusses, approved by the State of Wisconsin, Department of Safety and Professional Services, may be used as an approved roof framing system. The building plans shall indicate the approval number assigned by the Department of Safety and Professional Services. The maximum spacing of trusses shall be two feet on center.
Sheathing shall provide a flat base upon which the exterior finish can be applied. Common types permitted include boards, plywood, structural or nonstructural insulating boards and gypsum sheathing. Installation shall serve to minimize air infiltration and shall be in accord with the manufacturer's recommendations.
A. 
Wall sheathing.
(1) 
Sheathing required. Except as otherwise regulated, the outside of all frame exterior walls shall be covered with an approved wall sheathing material.
(2) 
Approved wall sheathing. Approved wall sheathing may be selected from the following table:
Exterior Wall Sheathing Table
Type
Minimum Thickness
(inches)
Maximum Stud Spacing
(inches o.c.)
Board - square edged
1 nom.
16
Board - edge matched
1 nom.
24
Plywood
5/16
16
Plywood
1/2
24
Gypsum - exterior grade
1/2
16
Approved fiber board
1/2
16
Expanded polystyrene*
1
24
High-density fiberglass*
1
24
NOTES:
*
Expanded polystyrene or high-density fiberglass sheathing is not suitable as a nailing base; exterior finish materials shall be attached with appropriate length fasteners and only at stud locations.
Materials other than listed may be approved upon submission of manufacturers published technical information and the approval of the Building Inspector.
(3) 
Joints of sheathing. Joints of sheathing shall be centered over studs. Sheathing shall be installed with tight-fitted joints and shall be fastened at each stud. Board sheathing shall be double nailed and, if wider than eight inches, be triple nailed at each stud. Plywood shall be fastened six inches o.c. at panel edges and 12 inches o.c. at intermediate supports. Fastening of other materials shall be in accord with the manufacturers published recommendations.
(4) 
Building paper. Building paper shall be used to cover any sheathing not water-resistive. All water-resistive sheathing shall be identified as such by the manufacturer's label on each piece of material. In all other cases, a minimum of 15 pounds saturated felt or paper shall be applied with a lap of four inches. Papers with vapor resistance exceeding 0.5 perm shall not be used as a covering on exterior walls.
B. 
Roof sheathing and roof decking.
(1) 
Roof sheathing.
(a) 
Roof sheathing installed 24 inches o.c. or less may be selected from the following table:
Roof Sheathing Table
Type of Material
Minimum Measured Thickness
(inches)
Plywood (flat roofs of less than 2 1/2:12 pitch)
5/8
Plywood (sloped roofs of 2 1/2:12 or over pitch)
1/2
Boards (solid sheathing)
5/8
Boards (spaced sheathing)
3/4
(b) 
Materials and installation methods other than listed may be approved upon submission of the manufacturers published recommendations and the approval of the Building Inspector. Such approval shall be limited to installations resulting in a uniform load deflection limit of 1/180 of span under live load plus dead load, 1/240 of span under live load only.
(2) 
Roof decking.
(a) 
Wood planks shall be tongue-and-groove or splined and at least two inches, nominal, in thickness. Planks shall terminate over supports unless the joints are end matched. All joints shall be parallel to and over the center of roof supports with not more than two adjacent planks breaking joints over the same support except at ends and at openings.
(b) 
Maximum span of two-inch plank shall not exceed the following:
[1] 
Planks continuous over two supports, eight feet.
[2] 
Planks over a single span, six feet.
[3] 
Other spans or thicknesses may be used when calculated according to standard engineering practice. Deflection shall be limited to 1/240 of span.
(3) 
Vapor barrier for roof decking. Vapor barrier for roof decking shall be installed between roof decking and insulation when the roof deck is to remain exposed as the finished ceiling.
(4) 
Fastening of sheathing and decking. Fastening of sheathing and decking shall be to each rafter, truss or roof support. Board sheathing shall be double-nailed and, if wider than eight inches, be tripled-nailed at each support. Plywood shall be fastened six inches o.c. at panel edges and 12 inches o.c. at intermediate supports. Roof decking shall be blind and surface-nailed and, if wider than eight inches, shall be tripled-nailed at each support.
Subfloor material shall provide a structurally adequate and suitable surface upon which finish floor covering shall be applied. Common materials permitted are board and plywood sheathings, planking, plywood and wood product underlayments.
A. 
Board subfloor.
(1) 
Minimum thickness. Minimum thickness shall be one inch nominal for joists spaced a maximum of 16 o.c.; width shall not exceed eight inches.
(2) 
Subfloor direction. Boards may be installed diagonal or at right angles to joists. When installed at right angles to joists, finish floor shall be installed across subfloor.
(3) 
Joints of subflooring. Joints of subflooring shall be centered over joists with cuts made parallel to joists. Not more than two adjacent boards may break joints on the same joist except at ends and at opening.
(4) 
Minimum clearance. Minimum clearance of at least 1/2 inch shall be maintained between subflooring and masonry or concrete walls.
(5) 
Subfloor as ceramic tile base. Joists may be beveled and ledger strips used to support subfloor for concrete setting bed. [Refer to § 756-26F(4) for method of reinforcing joists to support concrete setting bed.]
B. 
Plywood subfloor.
(1) 
Plywood. Plywood used for structural subflooring shall be of construction grades and shall be grade-stamped on each panel. The allowable loads and spans shall be limited to those identified on each panel, as follows:
Allowable Loads for Plywood Floor
Panel Identification Index
Thickness
(inches)
Maximum Floor Span
(inches o.c.)
30/12
5/8
12*
32/16
1/2, 5/8
16**
36/16
3/4
16**
42/20
5/8, 3/4, 7/8
20
48/24
3/4, 7/8
24
NOTES:
*
May be 16 inches o.c. if 25/32" stripflooring is installed at right angles to joists.
**
May be 24 inches o.c. if 25/32" stripflooring is installed at right angles to joists.
(2) 
Direction of installation. Plywood subflooring shall be applied continuously over two or more spans with the direction of the face grain perpendicular to the supporting joists.
C. 
Underlayment for resilient flooring.
(1) 
Underlayment shall be minimum 1/2 inch structural interior type or exterior type plywood or particle board. Particle board may not be used for underlayment except under carpeting. Other materials may be used when approved as suitable by the Building Inspector.
(2) 
Plywood shall be of at least "C plugged" grade.
(3) 
Hardboard shall be installed with smooth surface up.
(4) 
Nailing to subfloor shall be by type of nail and spacing recommended by the underlayment manufacturer.
D. 
Plank subfloor.
(1) 
Planks. Plank shall be tongue and groove or splined and at least two inches in thickness. Maximum width eight inches. Square-edge planks may be used where strip flooring with T and G edges is installed at right angles to plank or where a separate underlayment is provided.
(2) 
Joints. Joints shall be cut parallel to and over center of floor beams with not more than two adjacent planks breaking joists over the same support except at ends or openings.
(3) 
Maximum span. For two-inch plank, deck shall not exceed the following:
(a) 
Plank continuous over two spans: seven feet.
(b) 
Planks over single spans: five feet.
(c) 
Other spans may be used when calculated according to standard engineering practice. Deflection shall be limited to 1/360 of span.
(4) 
Nailing. Plank floor shall be blind and face nailed to floor beams in accord with the nailing schedule, Table No. 4.[1]
[1]
Editor's Note: Table No. 4 is included as an attachment to this chapter.
(5) 
Other loads. From bearing partitions, interior columns or other concentrated loads shall be supported independent from plank deck.
E. 
Combined thickness. Combined thickness of subfloor and underlay shall be minimum of one inch except as permitted by this chapter as single floor systems.
F. 
Single floor system.
(1) 
Plywood combination subfloor/underlayment, designed for a single floor system, shall be grade-stamped and comply with the following table:
Spans for Plywood Combination Subfloor/Layment
Species Group
Maximum Joist Spacing (o.c.)
16
20
24
1
1/2"
5/8"
3/4"
2, 3
5/8"
3/4"
7/8"
4
3/4"
7/8"
1"
(2) 
Wider spans may be permitted of 1 1/8 inch thick panels when installed according to manufacturers' published recommendations and when approved by the Building Inspector.