SPS 321.15(1)(a)(a) The dwelling and attached structures, such as decks and garages, shall be supported on a structural system designed to transmit and safely distribute the loads to the soil.
SPS 321.15(1)(b)
(b) The loads for determining the footing size shall include the weight of the live load, roof, walls, floors, pier or column, plus the weight of the structural system and the soil over the footing.
SPS 321.15(1)(c)
(c) Footings shall be sized to not exceed the allowable material stresses.
SPS 321.15(1)(d)
(d) The bearing area shall be at least equal to the area required to transfer the loads to the supporting soil without exceeding the bearing capacity of the soil.
SPS 321.15(1)(e)1.1. Structures supported on floating slabs or similar shallow foundations may not be physically attached to structures that are supported by footings that extend below the frost line unless an isolation joint is used between the structures, except as provided in subd.
2. This isolation shall extend for the full height of the structure.
SPS 321.15(2)
(2)
Size and type. Unless designed by structural analysis, unreinforced concrete footings shall comply with the following requirements:
SPS 321.15(2)(a)
(a) Continuous footings. The minimum width of the footing on each side of the foundation wall shall measure at least 4 inches wider than the wall. The footing depth shall be at least 8 inches nominal. Footing placed in unstable soil shall be formed. Lintels may be used in place of continuous footings when there is a change in footing elevation.
SPS 321.15 Note
Note: Unstable soil includes soils that are unable to support themselves at a 90 degree angle for the full depth of the footing.
SPS 321.15(2)(b)1.1. The minimum width and length of column or pier footings shall measure at least 2 feet by 2 feet.
SPS 321.15(2)(b)2.
2. The minimum depth of column or pier footings shall measure at least 12 inches nominal.
SPS 321.15(2)(c)
(c) Trench footings. Footings poured integrally with the wall may be used when soil conditions permit. The minimum width shall be at least 8 inches nominal.
SPS 321.15(2)(d)
(d) Chimney and fireplace footings. Footing for chimneys or fireplaces shall extend at least 4 inches on each side of the chimney or fireplace. The minimum depth shall measure at least 12 inches nominal.
SPS 321.15(2)(e)
(e) Floating slabs. Any dwelling supported on a floating slab on grade shall be designed through structural analysis.
SPS 321.15(2)(f)
(f) Deck footings. Decks attached to dwellings and detached decks which serve an exit shall be supported on a structural system designed to transmit and safely distribute the loads to the soil. Footings shall be sized to not exceed the allowable material stresses. The bearing area shall be at least equal to the area required to transfer the loads to the supporting soil without exceeding the bearing values of the soil.
SPS 321.15(3)
(3)
Soil-bearing capacity. No footing or foundation shall be placed on soil with a bearing capacity of less than 2,000 pounds per square foot unless the footing or foundation has been designed through structural analysis. The soil-bearing values of common soils may be determined through soil identification.
SPS 321.15 Note
Note: The department will accept the soil-bearing values for the types of soil listed in the following table:
- See PDF for table 
SPS 321.15(3)(a)
(a) Minimum soil-bearing values. If the soil located directly under a footing or foundation overlies a layer of soil having a smaller allowable bearing value, the smaller soil-bearing value shall be used.
SPS 321.15(3)(b)
(b) Unprepared fill material, organic material. No footing or foundation shall be placed upon unprepared fill material, organic soil, alluvial soil or mud unless the load will be supported. When requested, soil data shall be provided.
SPS 321.15 Note
Note: The decomposition of organic material in landfill sites established for the disposal of organic wastes may produce odorous, toxic and explosive concentrations of gas which may seep into buildings through storm sewers and similar underground utilities unless provisions are taken to release the gases to the atmosphere.
SPS 321.15 History
History: Cr.
Register, November, 1979, No. 287, eff. 6-1-80; am. (1) (a),
Register, January, 1989, No. 397, eff. 2-1-89; cr. (1) (f),
Register, March, 1992, No. 435, eff. 4-1-92; am. (1) (e),
Register, November, 1995, No. 479, eff. 12-1-95; am. (1) (e),
Register, March, 2001, No. 543, eff. 4-1-01;
CR 08-043: renum. (intro.), (1) and (2) to be (1), (2) and (3) and am. (1), (2) (b) and (e), cr. (1) (e)
Register March 2009 No. 639, eff. 4-1-09;
CR 15-041: renum. (1) (e) to (1) (e) 1. and am., cr. (1) (e) 2.
Register December 2015 No. 720, eff. 1-1-16.
SPS 321.16(1)(a)(a) Footings and foundations, including those for landings and stoops, shall be placed below the frost penetration level or at least 48 inches below adjacent grade, whichever is deeper, except as allowed under sub.
(2).
SPS 321.16(2)(a)(a) Frost protected shallow foundations shall be designed in accordance with ASCE–32 as adopted in Table 320.24-5.
SPS 321.16(2)(b)
(b) Portions of footings or foundations located directly under window areaways do not require frost protection provided the rest of the foundation is protected in accordance with this section.
SPS 321.16(2)(c)
(c) Footings and foundations may bear directly on bedrock less than 48 inches below adjacent grade provided all of the following conditions are met.
SPS 321.16(2)(c)2.
2. All clay in crevices of the rock shall be removed to the level of frost penetration or to 1.5 times the width of the rock crevice, whichever is less.
SPS 321.16(2)(c)3.
3. Provisions shall be taken to prevent water from collecting anywhere along the foundation.
SPS 321.16(2)(d)
(d) Subsection
(1) (a) does not apply to the footing for a ramp and its handrail posts unless the ramp abuts a frost-protected stoop or landing, in which case only the footing for that abutting end of the ramp is required to have the frost protection under sub.
(1) (a), such as by bearing onto the stoop or landing, so that a tripping hazard is not created.
SPS 321.16 History
History: Cr.
Register, November, 1979, No. 287, eff. 6-1-80; am. (intro.),
Register, February, 1985, No. 350, eff. 3-1-85; renum. (intro.) and (1) to be (1) and (2) and am. (2) (d), cr. (2) (e),
Register, January, 1989, No. 397, eff. 2-1-89; am. (1),
Register, November, 1995, No. 479, eff. 12-1-95; correction in (2) (e) made under s. 13.93 (2m) (b) 7., Stats.,
Register, March, 2001, No. 543;
CR 08-043: r. and recr.
Register March 2009 No. 639, eff. 4-1-09; correction in (2) (a) made under s. 13.92 (4) (b) 7., Stats.,
Register December 2011 No. 672;
CR 15-041: am. (1) (a), cr. (2) (d)
Register December 2015 No. 720, eff. 1-1-16.
SPS 321.17(1)(a)1.1. Except as provided under sub.
(2), a complete drain tile or pipe system shall be installed around the foundation of dwellings under construction where groundwater occurs above the bottom of the footing.
SPS 321.17(1)(a)2.
2. For the purposes of this section, a complete drain tile or pipe system includes all of the following:
SPS 321.17(1)(b)1.1. If a complete drain tile or pipe system is not required by natural conditions under par.
(a) or by a municipality or registered UDC inspection agency, a partial drain tile or pipe system may be installed.
SPS 321.17(1)(b)2.
2. For the purposes of this section, a partial drain tile or pipe system includes a means of discharging water from the tile or pipe and may include any of the other elements under par.
(a) 2. SPS 321.17 Note
Note: Means of discharging water include a sump pit, a crock or natural means of drainage to daylight.
SPS 321.17(2)(a)1.1. For new dwelling construction, a municipality or registered UDC inspection agency may determine the soil types and natural or seasonal groundwater levels for which a complete drain tile or pipe system is required.
SPS 321.17(2)(a)2.
2. For new dwelling construction, a municipality may not enact requirements for other than complete drain tile or pipe systems.
SPS 321.17(2)(b)
(b)
Alterations to an existing dwelling. For an alteration to an existing dwelling covered by this code, a municipality may not require a complete drain tile or pipe system.
SPS 321.17(2)(c)
(c)
Partial systems. Municipalities may allow partial drain tile or pipe systems for new dwellings under construction or existing dwellings.
SPS 321.17(3)
(3)
Material and installation requirements for required systems. SPS 321.17(3)(a)
(a)
General. Complete drain tile or pipe systems required by natural conditions under sub.
(1) (a) or by a municipality or registered UDC inspection agency shall comply with the requirements of this subsection.
SPS 321.17(3)(b)
(b)
Basement floor slabs. The basement slab shall be placed on at least 4 inches of clean graded sand, gravel or crushed stone.
SPS 321.17(3)(c)
(c)
Manufactured drainage systems. Manufactured drainage systems not meeting the requirements of this section shall be submitted to the department for review and approval prior to installation.
SPS 321.17(3)(d)
(d)
Drain tile or pipe installation. Drain tile or pipe used for foundation drainage shall comply with the following requirements:
SPS 321.17(3)(d)1.a.a. Except as allowed under subd.
1. b., the top of the tile or pipe shall be at or below the top of the footing.
SPS 321.17(3)(d)1.b.
b. Where the top of the footing is more than 4 inches below the bottom of the floor slab, tile or pipe is required on the interior of the foundation only and it shall be placed directly under the floor.
SPS 321.17 Note
Note: This situation will commonly occur with a walk-out basement.
SPS 321.17(3)(d)2.
2. Drain tile or pipe shall have an inside diameter of at least 3 inches.
SPS 321.17(3)(d)3.
3. Drain tile or pipe shall have open seams, joints or perforations to allow water to enter.
SPS 321.17(3)(d)4.
4. Where individual tiles are used, they shall be laid with
1/
8 inch open joints. Joints between tiles shall be covered with a strip of asphalt or tar impregnated felt.
SPS 321.17(3)(d)5.
5. The tile or pipe shall be placed upon at least 2 inches of coarse aggregate and shall be covered on the top and the side facing away from the dwelling with at least 12 inches of coarse aggregate that meets all of the following criteria:
SPS 321.17 Note
Note: A #8 sieve has square openings of 2.36 mm or 0.09 inch.
SPS 321.17 Note
Note: These specifications encompass aggregate sizes #6 and #67 per ASTM standard C 33. Of the two sizes, #6 is coarser.
SPS 321.17(3)(d)6.a.a. Bleeder tiles or pipes shall be provided at no more than 8-foot intervals to connect the exterior drain tile or pipe to the interior drain tile or pipe.
SPS 321.17(3)(d)6.c.
c. Direct connection of the bleeders is not required if the intersection of the bleeder with the tile or pipe is covered with a membrane or fabric that prevents soil and fines from entering the system.
SPS 321.17(3)(d)7.
7. The drain tiles or pipe that lead from the footing tiles to the sump pit shall be laid at a grade of at least
1/8 inch per foot leading to the sump pit. The remaining drain tiles or pipe shall be level or graded downward to the line leading to the sump pit.
SPS 321.17(3)(e)2.
2. The sump pit shall discharge to natural grade or be equipped with a pump.
SPS 321.17 Note
Note: The following is a reprint of a pertinent section of the plumbing code:
SPS 321.17 Note
SPS 382.36 (8) Sumps and pumps. (a) Sumps. 1. `General.' All storm building subdrains shall discharge into a sump, the contents of which shall be automatically lifted and discharged, dispersed or used in accordance with sub. (4).
SPS 321.17 Note
2. `Construction and installation'. a. Except as provided in subd. 2. c. and d., an interior sump shall have a rim extending at least one inch above the floor immediately adjacent to the sump.
