subch. IV of ch. SPS 322 Subchapter IV — Dwelling Thermal Envelope
SPS 322.30 SPS 322.30General design requirements.
SPS 322.30(1)(1)General. Dwelling thermal envelope insulation amounts and details shall be determined using one of the methods described in this subchapter.
SPS 322.30(2) (2)Infiltration.
SPS 322.30(2)(a)(a) Infiltration for heating design loads shall be calculated based on a maximum of 0.5 air change per hour in the heated space.
SPS 322.30(2)(b)1.1. If the proposed design takes credit for a reduced air change per hour level, documentation of the measures providing the reduction or the results of a post-construction blower door test conducted in accordance ASTM E 779 shall be provided to the department.
SPS 322.30(2)(b)2. 2. The minimum air change per hour rate may not be less than 0.2, unless mechanical ventilation is provided.
SPS 322.30(3) (3)Basements and crawl spaces. Where basement and crawl space walls are part of the dwelling thermal envelope, their R-values and U-factors shall be based on the wall components. Adjacent soil may not be considered in the determination.
SPS 322.30(4) (4)Garages.
SPS 322.30(4)(a)(a) Except as provided under par. (b), a garage may not be provided with any supplemental heat unless all of the following conditions are met:
SPS 322.30 Note Note: Because of the scope of this chapter, the requirements under this subsection apply only to heat generated from non-renewable sources.
SPS 322.30(4)(a)1. 1. The dwelling shall be thermally isolated from the garage.
SPS 322.30(4)(a)2. 2. The garage floor, ceiling and walls shall be provided with a vapor retarder in accordance with s. SPS 322.38.
SPS 322.30(4)(a)3. 3. All building elements shall meet the requirements of s. SPS 322.31.
SPS 322.30(4)(b) (b) The thermal envelope requirements under par. (a) are not required if all of the following conditions are met:
SPS 322.30(4)(b)1. 1. The thermostat is permanently limited to a maximum of 50°F.
SPS 322.30(4)(b)2. 2. Heating equipment is either separate from the dwelling unit equipment or installed as a separate zone.
SPS 322.30(4)(b)3. 3. Separate heating equipment shall be sized to provide a maximum indoor temperature of 50°F.
SPS 322.30(5) (5)Masonry veneer. When insulation is placed on the exterior of a foundation supporting a masonry veneer exterior, the horizontal foundation surface supporting the veneer is not required to be insulated to satisfy the foundation insulation requirement.
SPS 322.30 History History: CR 08-043: cr. Register March 2009 No. 639, eff. 4-1-09; correction in (4) (a) 2., 3. made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672.
SPS 322.31 SPS 322.31Prescriptive insulation and fenestration criteria.
SPS 322.31(1)(1)Requirements.
SPS 322.31(1)(a)(a) Except as specifically provided under this subchapter, dwellings using the prescriptive method shall meet the requirements of Table 322.31-1 or 322.31-2.
SPS 322.31(1)(b) (b) In Tables 322.31-1 and 322.31-2, zone 2 consists of the following 15 northern counties: Ashland, Bayfield, Burnett, Douglas, Florence, Forest, Iron, Langlade, Lincoln, Oneida, Price, Sawyer, Taylor, Vilas and Washburn. Zone 1 consists of all other counties not included in zone 2.
SPS 322.31(2) (2)Thermal envelope.
SPS 322.31(2)(a)(a) General. If the total dwelling thermal envelope UA is less than or equal to the total UA resulting from using the U-factors in Table 322.31-2 multiplied by the same assembly area as in the proposed building, the dwelling is in compliance with this chapter. The UA calculation shall be done using a method consistent with the ASHRAE Handbook of Fundamentals and shall include the thermal bridging effects of framing materials.
SPS 322.31 Note Note: UA is equal to the product of the U-factor times the assembly area.
SPS 322.31 Note Note: REScheck is an acceptable software program for determining compliance with this section.
SPS 322.31(2)(b) (b) Software version. If a REScheck software program is used to show compliance with this section, a version approved by the department shall be used.
SPS 322.31 Note Note: The IECC 2009 version of REScheck meets the thermal envelope requirements of this code.
SPS 322.31(3) (3)Appliance efficiency.
SPS 322.31(3)(a)(a) Except as allowed under par. (b) and s. SPS 322.46, oil-fired and gas-fired furnaces and boilers shall meet the minimum efficiency requirements in Table 322.31-3.
SPS 322.31(3)(b) (b) In new construction, an oil-fired or gas-fired furnace or boiler meeting the federal efficiency standard but not the requirements of Table 322.31-3 may be installed if the dwelling thermal envelope requirements of Table 322.31-4 are met.
TABLE 322.31-1
TABLE 322.31-2
EQUIVALENT U-FACTORS - See PDF for table PDF - See PDF for table PDF
TABLE 322.31-4
a - See PDF for table PDF
SPS 322.31 History History: CR 08-043: cr. Register March 2009 No. 639, eff. 4-1-09; EmR0917: emerg. am. (2) (b), eff. 9-5-09; CR 09-072: am. (2) (b) Register March 2010 No. 651, eff. 4-1-10; CR 09-104: am. Tables 22.31-1 and 22.31-4 Register December 2010 No. 660, eff. 1-1-11; correction in (1) (a), (b), (2) (a), (b), (3) (a), (b), Table 322.31-1, Table 322.31-4 made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672l; CR 15-041: am. Table 322.31-1, Table 322.31-2, Table 322.31-4 Register December 2015 No. 720, eff. 1-1-16.
SPS 322.32 SPS 322.32Specific insulation requirements.
SPS 322.32(1)(1)Ceilings with attic spaces.
SPS 322.32(1)(a)(a) R-38 will satisfy the ceiling R-value requirement for a dwelling where the full height of uncompressed R-38 insulation extends over the wall top plate at the eaves.
SPS 322.32(1)(b) (b) An attic-access cover shall be weatherstripped and insulated to a level equivalent to the insulation on the surrounding surfaces when the attic is an unconditioned space. A wood framed or equivalent baffle or retainer is required to be provided when loose fill insulation is installed, the purpose of which is to prevent loose fill insulation from spilling into the living space when the attic access is opened, and to provide a permanent means of maintaining the installed R-value of the loose fill insulation.
SPS 322.32(2) (2)Ceilings without attic spaces. Where the design of the roof or ceiling assembly does not allow sufficient space for the required R-49 insulation, the minimum required insulation for the roof or ceiling assembly shall be R-30. This reduction of insulation shall be limited to 500 square feet of ceiling area.
SPS 322.32(3) (3)Mass walls. The requirements of Table 322.31-1 are applicable to mass walls.
SPS 322.32(4) (4)Steel-frame ceilings, walls and floors.
SPS 322.32(4)(a)(a) Steel-frame ceilings, walls and floors shall meet the insulation requirements of Table 322.32 or shall meet the U-factor requirements in Table 322.31-2.
SPS 322.32(4)(b) (b) The calculation of the U-factor for a steel-frame envelope assembly shall use a series-parallel path calculation method.
SPS 322.32(5) (5)Floors. Floor insulation shall be installed to maintain permanent contact with the underside of the subfloor decking.
SPS 322.32(6) (6)Basement walls.
SPS 322.32(6)(a)(a) Walls associated with conditioned basements shall be insulated from the top of the basement wall down to the basement floor.
SPS 322.32(6)(b) (b) Walls associated with unconditioned basements shall meet the requirement in par. (a) unless the floor overhead is insulated in accordance with Table 322.31-1.
SPS 322.32(6)(c) (c) Where the total basement wall area is less than 50 percent below grade, the entire wall area, including the below-grade portion, is included as part of the area of exterior walls.
SPS 322.32(7) (7)Box sill and rim joist spaces. Box sills and joist spaces at outside walls shall be insulated to the required wall R-value with air-impermeable insulation that is sealed on all sides to all framing members and the foundation, or with air-permeable insulation held in place as required under s. SPS 322.21 (1).
SPS 322.32(8) (8)Overhang joist spaces.
SPS 322.32(8)(a)(a) Joist spaces that extend beyond exterior walls shall be insulated with an R-value of 30 or higher with insulation that completely fills the cavity including over the top of the exterior wall supporting the joists.
SPS 322.32(8)(b) (b) The joist space insulation shall be air sealed either by using an air-impermeable insulation that is sealed to all framing members or by covering the insulation with a rigid material that is caulked or sealed to all framing members.
SPS 322.32(8)(c) (c) If piping that is subject to freezing is located in the joist space, additional insulation shall be provided on the unconditioned side of the space.
SPS 322.32(9) (9)Wall insulation.
SPS 322.32(9)(a)(a) Except for closed-cell sprayed foam, wall insulation shall completely fill the wall cavity.
SPS 322.32(9)(b) (b) The vertical and flared walls in a skylight shall meet the insulation requirements for walls. Tube skylights shall be insulated per the manufacturer's recommendations. - See PDF for table PDF
SPS 322.32 History History: CR 08-043: cr. Register March 2009 No. 639, eff. 4-1-09; correction in (3) (a), (b), (4) (a), (6) (b), (7) made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672; CR 15-041: renum. (1) to (1) (a), cr. (1) (b), renum. (3) (a) to (3) and am., r. (3) (b), renum. (9) to (9) (a), cr. (9) (b) Register December 2015 No. 720, eff. 1-1-16.
SPS 322.33 SPS 322.33Slab floors.
SPS 322.33(1) (1)Heated or unheated slabs.
SPS 322.33(1)(a)(a) Any heated or unheated slab floor, the bottom of which is less than 12 inches below adjacent grade, shall be provided with perimeter insulation in accordance with Table 322.31-1 or Table 322.31-4, except as provided in par. (b).
SPS 322.33(1)(b) (b) At the threshold or the base of any door opening that leads directly to the exterior of the structure, the vertical perimeter insulation shall be at least R-5, excluding all garage doors.
SPS 322.33(2) (2)Heated slabs. In addition to meeting the requirement under sub. (1), if applicable, heated slab floors of any depth below grade shall meet the under-slab R-value requirement in accordance with Table 322.31-1 or Table 322.31-4.
SPS 322.33(3) (3)Details.
SPS 322.33(3)(a)(a) The top edge of insulation installed between the exterior wall and the edge of the interior slab may be cut at a 45 degree angle away from the exterior wall.
SPS 322.33(3)(b) (b) Horizontal insulation extending outside of the foundation shall be covered by soil a minimum of 10 inches thick or by pavement.
SPS 322.33(3)(c) (c) Insulation on a foundation wall for a basement may be interrupted at the junction with a foundation wall.
SPS 322.33 Note Note: See Appendix for further explanatory materials.
SPS 322.33 History History: CR 08-043: cr. Register March 2009 No. 639, eff. 4-1-09; CR 09-104: am. (1), (2) Register December 2010 No. 660, eff. 1-1-11; correction in (1), (2) made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672; CR 15-041: renum. (1) to (1) (a) and am., cr. (1) (b), (3) (c) Register December 2015 No. 720, eff. 1-1-16.
SPS 322.34 SPS 322.34Crawl spaces.
SPS 322.34(1) (1)Frost protection. If the bottom of the crawl space serving as the dwelling foundation is less than 48 inches below adjacent grade, the foundation shall be frost protected in accordance with Table 322.31-1 for frost protected slabs.
SPS 322.34(2) (2)Vapor retarder. Any exposed earth in crawl spaces shall be covered with a continuous vapor retarder.
SPS 322.34(2)(b) (b) All decayable organic material, including topsoil, shall be removed from crawl space floors prior to placing the vapor retarder.
SPS 322.34(2)(c) (c) All joints of the vapor retarder shall overlap by 6 inches and be sealed or taped.
SPS 322.34(2)(d) (d) The edges of the vapor retarder shall extend at least 6 inches up the foundation wall and shall be attached and sealed to the foundation wall or insulation.
SPS 322.34(3) (3)crawl spaces.
SPS 322.34(3)(a)(a) Crawl space walls shall be insulated in accordance with Table 322.31-1.
SPS 322.34(3)(b) (b) Crawl space wall insulation shall be permanently fastened to the wall and shall extend the entire height of the wall.
SPS 322.34 History History: CR 08-043: cr. Register March 2009 No. 639, eff. 4-1-09; correction in (1), (3) (c), (4) (a), (c) made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672; CR 15-041: am. (2) (d) Register December 2015 No. 720, eff. 1-1-16; CR 15-090: r. (3), (4) (c), renum. (4) to (3) and am. Register May 2016 No. 725, eff. 6-1-16.
SPS 322.35 SPS 322.35Thermally isolated sunrooms.
SPS 322.35(1)(1) The minimum opaque ceiling insulation R-value shall be R-24. The minimum opaque wall R-value shall be R-13.
SPS 322.35(2) (2) The maximum fenestration U-factor shall be 0.50 and the maximum skylight U-factor shall be 0.75.
SPS 322.35(3) (3) New walls, windows and doors separating a sunroom from conditioned space shall meet the building thermal envelope requirements.
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.