Section 600. Idaho Building Codes

Pursuant to Sections 39-4109 and 39-4109A, Idaho Code, the Board adopts the following international codes wit h identified amendments: (7-1-24) 01. International Building Code. The 2018 Edition, including appendices pertaining to buildin g accessibility, with the following amendments: (7-1-24) a. Delete Section 305.2.3 and replace with the following: 305.2.3 Twelve (12) or fewer children in a dwelling unit. A facility such as the above within a dwelling unit and having twelve (12) or fewer children receivin g such day care shall be classified as a Group R-3 occupancy or shall comply with the International Residential Code. (7-1-24) i. Delete Section 308.2.4 and replace with the following: 308.2.4 Five (5) or fewer persons receivin g custodial care. A facility with five (5) or fewer persons receiving custodial care shall be classified as a Group R- 3 occupancy or shall comply with the International Residential Code. (7-1-24) ii. Delete Section 308.3.2 and replace with the following: 308.3.2 Five (5) or fewer persons receivin g medical care. A facility with five (5) or fewer persons receiving medical care shall be classified as a Group R-3 occupancy. (7-1-24) iii. Delete Section 308.5.4 and replace with the following: 308.5.4 Persons receiving care in a dwellin g unit. A facility such as the above within a dwelling unit and having twelve (12) or fewer children receiving day car e or having five (5) or fewer persons receiving custodial care shall be classified as a Group R-3 occupancy or shal l comply with the International Residential Code. (7-1-24) b. Section 310.4: Add the following: “Dwelling units providing day care for twelve (12) or fewe r children”. (7-1-24) c. Section 310.4.1. Delete and replace with the following: 310.4.1 Care facilities within a dwelling

y car e or having five (5) or fewer persons receiving custodial care shall be classified as a Group R-3 occupancy or shal l comply with the International Residential Code. (7-1-24) b. Section 310.4: Add the following: “Dwelling units providing day care for twelve (12) or fewe r children”. (7-1-24) c. Section 310.4.1. Delete and replace with the following: 310.4.1 Care facilities within a dwelling . Care facilities for twelve (12) or fewer children receiving day care or for five (5) or fewer persons receiving persona l care or custodial care that are within a one- or two-family dwelling are permitted to comply with the Internationa l Residential Code. (7-1-24) d. Add new Section 602.1.2: 602.1.2 Alternative provisions. As an alternative to the constructio n types defined in Sections 602.2 through 602.5, buildings and structures erected or to be erected, altered, or extende d in height or area may be classified as construction type IV-A, IV-B, or IV-C in accordance with the provision s adopted in Paragraph 004.01.b of these rules. Buildings and structures classified as construction type IV-A, IV-B, or IV-C shall comply with the provisions adopted in Paragraph 004.01.h of these rules and all other applicabl e provisions of this code. (7-1-24) e. Table 2902.1 Minimum Number of Required Plumbing Fixtures. Delete footnote ͤ and replace wit h the following: e For business occupancies, excluding restaurants, and mercantile occupancies with an occupant loa d of thirty (30) or fewer, service sinks shall not be required. (7-1-24) f. Table 2902.1 Minimum Number of Required Plumbing Fixtures. Delete footnote f and replace wit h the following: f Drinking fountains are not required for an occupant load of thirty (30) or fewer. (7-1-24) g. Section 3113 Relocatable Buildings. Delete. (7-1-24) 02. International Building Code, 2021 Edition. The following provisions of the 2021 Edition relate d to mass timber construction: (7-1-24) a

Table 2902.1 Minimum Number of Required Plumbing Fixtures. Delete footnote f and replace wit h the following: f Drinking fountains are not required for an occupant load of thirty (30) or fewer. (7-1-24) g. Section 3113 Relocatable Buildings. Delete. (7-1-24) 02. International Building Code, 2021 Edition. The following provisions of the 2021 Edition relate d to mass timber construction: (7-1-24) a. In Section 202, the definitions of the terms MASS TIMBER; NONCOMBUSTIBL E PROTECTION (FOR MASS TIMBER); SECONDARY STRUCTURAL MEMBERS; and WALL, LOAD BEARING; (7-1-24) b. Sections 403.3.2, 508.4.4.1, 509.4.1.1, 602.4 through 602.4.3.6, 703.6, 703.7, 704.4, 722.7 throug h 722.7.2.2, 1705.5.3, 1705.20, 2304.10.1, 3313.1 through 3313.3.3, 3313.5, and 3314.1; (7-1-24) c. Tables 504.3, 504.4, 506.2, 601, 705.5, 722.7.1(1), 722.7.1(2), and 1705.5.3, including any not e following each table adopted in this subparagraph; and (7-1-24) d. In Chapter 35, the referenced standards ANSI/APA PRG 320—2019: Standard for Performance- rated Cross-laminated Timber, referenced in Sections 602.4 and 2303.1.4, and ASTM D3498—03(2011): Standar d Specification for Adhesives for Field-Gluing Plywood to Lumber Framing for Floor Systems, referenced in Sectio n 703.7. (7-1-24) 03. International Residential Code, 2018 Edition. Parts I, II, III, and IX of the 2018 Edition for on e (1)- and two (2)- family dwellings, with the following amendments: (7-1-24) a. Section R101.2 Scope. Delete the exception and replace with the following: Exception: Th e following shall also be permitted to be constructed in accordance with this code: 1. Owner-occupied lodging house s with five (5) or fewer guestrooms and ten (10) or fewer total occupants. 2. A care facility with five (5) or fewe r persons receiving custodial care within a dwelling unit or single-family dwelling. 3. A care facility for five (5) o r fewer persons receiving personal care that are within a dwelling unit or single-family dwelling. 4

ed in accordance with this code: 1. Owner-occupied lodging house s with five (5) or fewer guestrooms and ten (10) or fewer total occupants. 2. A care facility with five (5) or fewe r persons receiving custodial care within a dwelling unit or single-family dwelling. 3. A care facility for five (5) o r fewer persons receiving personal care that are within a dwelling unit or single-family dwelling. 4. A care facility wit h twelve (12) or fewer children receiving day care within a dwelling unit or single-family dwelling. (7-1-24) b. Section R105.2. Amend Item number 7 under the “Building” subheading Replace the words “24 inches (610 mm)” with “four (4) feet (1219) mm)” (7-1-24) c. Section R105.2. Add the following exemption under the “Building” subheading: 11. Flag poles. (7-1-24) d. Section R301.2.1.2 Protection of Openings. Delete. (7-1-24) e. Table R302.1(1). Delete and replace with the following: TABLE R302.1(1) - EXTERIOR WALLS MINIMUM FIRE MINIMUM FIRE-RESISTANCE EXTERIOR WALL ELEMENT SEPARATION RATING DISTANCE 1 hour-tested in accordance with ASTM E 119, UL263, or Fire-resistance rated Section 703.3 of the International < 3 feet Walls Building Code with exposure from both sides Not fire-resistance rated 0 hours ≥ 3 feet 1 hour on the underside, or Fire-resistance rated heavy timber, or fire ≥ 2 feet to < 3 feet Projections a,b retardant-treated wood Not fire-resistance rated 0 hours ≥ 3 feet Not allowed N/A < 3 feet Openings in 25% maximum of wall area 0 hours ≥ 3 feet to < 5 feet Walls Unlimited 0 hours 5 feet MINIMUM FIRE MINIMUM FIRE-RESISTANCE EXTERIOR WALL ELEMENT SEPARATION RATING DISTANCE Comply with Section R302.4 < 3 feet Penetrations All None required ≥ 3 feet For SI: 1 foot = 304.8 mm. N/A = Not Applicable aThe fire-resistance rating shall be permitted to be reduced to zero (0) hours on the underside of the eav e overhang if fireblocking is provided from the wall top plate to the underside of the roof sheathing

UM FIRE-RESISTANCE EXTERIOR WALL ELEMENT SEPARATION RATING DISTANCE Comply with Section R302.4 < 3 feet Penetrations All None required ≥ 3 feet For SI: 1 foot = 304.8 mm. N/A = Not Applicable aThe fire-resistance rating shall be permitted to be reduced to zero (0) hours on the underside of the eav e overhang if fireblocking is provided from the wall top plate to the underside of the roof sheathing. bThe fire-resistance rating shall be permitted to be reduced to zero (0) hours on the underside of the rak e overhang where gable vent openings are not installed. (7-1-24) f. Delete Table R302.6 Dwelling-Garage Separation and replace with the following table: Separation Material From the residence, attics, and habitable rooms above the garage Not less than 5/8-inch Type X gypsum board or Structure(s) supporting floor/ceiling assemblies used for equivalent applied to the garage side separation required by this section Not less than 5/8-inch Type X gypsum board or Garages located less than 3 feet from a dwelling unit on equivalent applied to the interior side of exterior walls that the same lot are within this area (7-1-24) g. Section R302.13 Fire protection of floors. Delete. (7-1-24) h. Section R303.4. Delete and replace with the following: Mechanical Ventilation. Dwelling unit s shall be provided with whole-house mechanical ventilation in accordance with Section M1505.4. (7-1-24) i. Section R313.1 Townhouse automatic fire sprinkler systems. Delete the exception and replace wit h the following: Exception: Automatic residential fire sprinkler systems shall not be required in townhouses where either two (2) one (1)-hour fire-resistance-rated walls or a common two (2)-hour fire-resistance rated wall, a s specified in item number 2 of Section R302.2.2 is installed between dwelling units or when additions or alteration s are made to existing townhouses that do not have an automatic residential fire sprinkler system installed. (7-1-24) j. Section R313.2 One- and two-family dwellings automatic fire sprinkler systems. Delete

esistance-rated walls or a common two (2)-hour fire-resistance rated wall, a s specified in item number 2 of Section R302.2.2 is installed between dwelling units or when additions or alteration s are made to existing townhouses that do not have an automatic residential fire sprinkler system installed. (7-1-24) j. Section R313.2 One- and two-family dwellings automatic fire sprinkler systems. Delete. (7-1-24) k. Section R314.2.2 Alterations, repairs and additions Exception Item #2. Delete. (7-1-24) l. Section R315.2.2 Alterations, repairs and additions Exception Item #2. Delete. (7-1-24) m. Section R322.1.10 As-built elevation documentation. Delete. (7-1-24) n. Tables R403 Minimum Depth (D) and Width (W) of Crushed Stone Footings (inches), R403.1(1 ) Minimum Width and Thickness for Concrete Footings for Light-Frame Construction (inches), R403.1(2) Minimu m Width and Thickness for Concrete Footings for Light-Frame Construction and Brick Veneer (inches), and R403.1(3 ) Minimum Width and Thickness for Concrete Footings with Cast-In-Place or Fully Grouted Masonry Wal l Construction (inches). Delete. (7-1-24) o. Add the following as Table R403.1: (7-1-24) TABLE R403.1 a MINIMUM WIDTH OF CONCRETE, PRECAST, OR MASONRY FOOTINGS (inches) LOAD-BEARING VALUE OF SOIL (psf) 1,500 2,000 3,000 ≥ 4,000 Conventional light-frame construction 1-Story 12 12 12 12 2-Story 15 12 12 12 3-Story 23 17 12 12 4-inch brick veneer over light frame or 8-inch hollow concrete masonry 1-Story 12 12 12 12 2-Story 21 16 12 12 3-Story 32 24 16 12 8-inch solid or fully grouted masonry 1-Story 16 12 12 12 2-Story 29 21 14 12 3-Story 42 32 21 16 For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa. aWhere minimum footing width is twelve (12) inches, use of a single wythe of solid or fully grouted twelve (12)-inc h nominal concrete masonry units is permitted. (7-1-24) p. Section R403.1.1. Delete and replace with the following: R403.1.1 Minimum size

fully grouted masonry 1-Story 16 12 12 12 2-Story 29 21 14 12 3-Story 42 32 21 16 For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa. aWhere minimum footing width is twelve (12) inches, use of a single wythe of solid or fully grouted twelve (12)-inc h nominal concrete masonry units is permitted. (7-1-24) p. Section R403.1.1. Delete and replace with the following: R403.1.1 Minimum size. Minimum size s for concrete and masonry footings shall be as set forth in Table R403.1 and Figure R403.1(1). The footing width (W ) shall be based on the load bearing value of the soil in accordance with Table R401.4.1. Spread footings shall be at least six (6) inches in thickness (T). Footing projections (P) shall be at least two (2) inches and shall not exceed th e thickness of the footing. The size of footings supporting piers and columns shall be based on the tributary load an d allowable soil pressure in accordance with Table R401.4.1. Footings for wood foundations shall be in accordanc e with the details set forth in Section R403.2 and Figures R403.1(2) and R403.1(3). (7-1-24) q. Section R602.10. Delete and replace with the following: Buildings shall be braced in accordanc e with this Section or, when applicable Section R602.12, or the most current edition of APA System Report SR-102 a s an alternate method. Where a building, or portion thereof, does not comply with one (1) or more of the bracing requirements in this Section, those portions shall be designed and constructed in accordance with Section R301.1. (7-1-24) 04. International Existing Building Code. 2018 Edition. (7-1-24) 05. International Energy Conservation Code – Commercial Provisions. The 2018 Edition with th e following amendments: (7-1-24) a. Add new Section C101.5.2: C101.5.2 Industrial, electronic, and manufacturing equipment . Buildings or portions thereof that are heated or cooled exclusively to maintain the required operating temperature o f industrial, electronic, or manufacturing equipment shall be exempt from the provisions of this code

n Code – Commercial Provisions. The 2018 Edition with th e following amendments: (7-1-24) a. Add new Section C101.5.2: C101.5.2 Industrial, electronic, and manufacturing equipment . Buildings or portions thereof that are heated or cooled exclusively to maintain the required operating temperature o f industrial, electronic, or manufacturing equipment shall be exempt from the provisions of this code. Such buildings o r portions thereof shall be separated from connected conditioned space by building thermal envelope assemblie s complying with this code. (7-1-24) b. Add the following Exemptions to section C402.1.1: (7-1-24) i. Exemption 4. Accessory utility and storage buildings and sports practice buildings accessory to A, B, and E occupancies where buildings maintain no heating or cooling or where intermittent heating and coolin g systems are installed. (7-1-24) ii. Exemption 5. Buildings for domestic water wells, irrigation wells, sewer pump facilities, and sewe r lift station buildings where equipment produces internal heat loads and where intermittent heating or cooling i s provided to prevent freezing or overheating of equipment. (7-1-24) c. Add the following as exception number 7 under Section C403.5 Economizers (Prescriptive): 7 . Unusual outdoor air contaminate conditions – Systems where special outside air filtration and treatment for th e reduction and treatment of unusual outdoor contaminants, makes an air economizer infeasible. (7-1-24) 06. International Energy Conservation Code – Residential Provisions. The 2018 Edition with th e following amendments: (7-1-24) a. R202 General Definitions. Add the following to the definition of “Conditioned Space”: Thi s definition shall not apply to garage spaces or other similar spaces where heating or cooling is installed for fros t protection or intermittent use. (7-1-24) b. Table R402.1.2 Insulation and Fenestration Requirements by Component

ntial Provisions. The 2018 Edition with th e following amendments: (7-1-24) a. R202 General Definitions. Add the following to the definition of “Conditioned Space”: Thi s definition shall not apply to garage spaces or other similar spaces where heating or cooling is installed for fros t protection or intermittent use. (7-1-24) b. Table R402.1.2 Insulation and Fenestration Requirements by Component. Delete the rows i n climate zones “5 and Marine 4” and “6” and replace with the following: TABLE R402.1.2 INSULATION AND FENESTRATION REQUIREMENTS BY COMPONENT a d Climate Fenestration Skylight b Glazed Ceiling F W ra o m od e Mass Wall Floor Basement c R S -V la a b lue Crawlspace c b Fenestration i Wall Wall Zone U- Factor U-factor b, e R-Value Wall R-Value R-Value & SHGC R-Value R-Value R-Value Depth 20 or g 5 0.32 0.55 NR 38 h 13/17 30 15/19 10, 2 ft 15/19 13+5 22 or g 6 0.30 0.55 NR 49 h 15/20 30 15/19 10, 4 ft 15/19 13+5 (7-1-24) c. Table R402.1.2 - Insulation and Fenestration Requirements by Component. Add the following a s footnote k to the Table title: k. For residential log home building thermal envelope construction requirements se e Section R402.6. (7-1-24) d. Table R402.1.4 Equivalent U-Factors. Delete the rows in climate zones “5 and Marine 4” and “6” and replace with the following: TABLE R402.1.4 EQUIVALENT U-FACTORS a Basement Crawlspace Climate Fenestration Skylight Ceiling Frame Wall Mass Wall Floor b Wall Wall Zone U-factor U-factor U-factor U-factor U-factor U-factor U-factor U-factor 5 0.32 0.55 0.030 0.060 0.082 0.033 0.050 0.055 TABLE R402.1.4 EQUIVALENT U-FACTORS a Basement Crawlspace Climate Fenestration Skylight Ceiling Frame Wall Mass Wall Floor b Wall Wall Zone U-factor U-factor U-factor U-factor U-factor U-factor U-factor U-factor 6 0.30 0.55 0.026 0.057 0.060 0.033 0.050 0.055 (7-1-24) e. Section R402.4.1.2. Add the following exception: Visual Inspection. The Permit Holder wil l determine at the time of permit application the method of determining building envelope tightness

mate Fenestration Skylight Ceiling Frame Wall Mass Wall Floor b Wall Wall Zone U-factor U-factor U-factor U-factor U-factor U-factor U-factor U-factor 6 0.30 0.55 0.026 0.057 0.060 0.033 0.050 0.055 (7-1-24) e. Section R402.4.1.2. Add the following exception: Visual Inspection. The Permit Holder wil l determine at the time of permit application the method of determining building envelope tightness. A visua l inspection shall be considered acceptable in lieu of testing when the items listed in Table R402.4.1.1, applicable to th e method of construction, are field verified. (7-1-24) f. Add new Section R402.6: R402.6 Residential log home thermal envelope. Residential log hom e construction shall comply with Section R401 (General), Section R402.4 (Air leakage), Section R402.5 (Maximu m fenestration U-factor and SHGC), Section R403.1 (Controls), the mandatory sections of Sections R403.3 throug h R403.9, Section R404 (Electrical Power and Lighting Systems), and either 1., 2., or 3. as follows: 1. Sections R402. 2 through R402.3, Section R403.3.1 (Insulation), Section R404.1 (Lightning equipment), and Table R402.6 (Log Hom e Prescriptive Thermal Envelope Requirements by Component). 2. Section R405 (Simulated Performance Alternative) . 3. REScheck (U.S. Department of Energy Building Codes Program). (7-1-24) g. Add new Table R402.6: TABLE R402.6 LOG HOME PRESCRIPTIVE THERMAL ENVELOPE REQUIREMENTS BY COMPONENT For SI: 1 foot = 304.8 mm. Min. Slab Crawl Glazed Average Basement Climate Fenestration Skylight Ceiling Floor R-value Space a Fenestration Log Wall Zone U-factor U-factor R-value R-value d & Wall SHGC Size In R-value b d Depth R-value Inches 5, 6 - High efficiency 0.32 0.60 NR 49 5 30 15/19 10, 4 ft. 10/13 equipment c path a The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration. b R-5 shall be added to the required slab edge R-values for heated slabs

Floor R-value Space a Fenestration Log Wall Zone U-factor U-factor R-value R-value d & Wall SHGC Size In R-value b d Depth R-value Inches 5, 6 - High efficiency 0.32 0.60 NR 49 5 30 15/19 10, 4 ft. 10/13 equipment c path a The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration. b R-5 shall be added to the required slab edge R-values for heated slabs. c 90% AFUE natural gas or propane, 84% AFUE oil, or 15 SEER heat pump heating equipment (zonal electric resistance heating equipment such as electric base board electric resistance heating equipment as the sole source for heating is con- sidered compliant with the high efficiency equipment path). d “15/19” means R-15 continuous insulated sheathing on the interior or exterior of the home or R-19 cavity insulation at the interior of the basement wall. “15/19” shall be permitted to be met with R-13 cavity insulation on the interior of the basement wall plus R-5 continuous insulated sheathing on the interior or exterior of the home. “10/13” means R-10 continuous insu- lated sheathing on the interior or exterior of the home or R-13 cavity insulation at the interior of the basement wall. TABLE R402.6 LOG HOME PRESCRIPTIVE THERMAL ENVELOPE REQUIREMENTS BY COMPONENT For SI: 1 foot = 304.8 mm. Min. Slab Crawl Glazed Average Basement Climate Fenestration Skylight Ceiling Floor R-value Space a Fenestration Log Wall Zone U-factor U-factor R-value R-value d & Wall SHGC Size In R-value b d Depth R-value Inches 5 0.32 0.60 NR 49 8 30 10/13 10, 2 ft. 10/13 6 0.30 0.60 NR 49 8 30 15/19 10, 4 ft. 10/13 a The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration. b R-5 shall be added to the required slab edge R-values for heated slabs

-value Space a Fenestration Log Wall Zone U-factor U-factor R-value R-value d & Wall SHGC Size In R-value b d Depth R-value Inches 5 0.32 0.60 NR 49 8 30 10/13 10, 2 ft. 10/13 6 0.30 0.60 NR 49 8 30 15/19 10, 4 ft. 10/13 a The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration. b R-5 shall be added to the required slab edge R-values for heated slabs. c 90% AFUE natural gas or propane, 84% AFUE oil, or 15 SEER heat pump heating equipment (zonal electric resistance heating equipment such as electric base board electric resistance heating equipment as the sole source for heating is con- sidered compliant with the high efficiency equipment path). d “15/19” means R-15 continuous insulated sheathing on the interior or exterior of the home or R-19 cavity insulation at the interior of the basement wall. “15/19” shall be permitted to be met with R-13 cavity insulation on the interior of the basement wall plus R-5 continuous insulated sheathing on the interior or exterior of the home. “10/13” means R-10 continuous insu- lated sheathing on the interior or exterior of the home or R-13 cavity insulation at the interior of the basement wall. (7-1-24) 601. – 999. (RESERVED)