City of Blackfoot, Idaho - Building & Safety Department

City of Blackfoot, Idaho

city

157 N Broadway, Blackfoot, ID 83221

Required

Required

LOCALLY ENACTED, ON A STATE-MANDATED EDITION, AND THE LOCAL ADOPTION FLOATS WITH THE STATE. The operative instrument is Blackfoot City Code Title 10, Chapter 2, Building Code, section 10-2-1, Building and Residential Codes Adopted: "...being marked and designated as the building code, current edition as adopted by the state, published by the International Conference Of Building Officials, but excepting therefrom the requirements for automatic sprinkler systems in three-unit and four-unit group R buildings, and adopting the residential code, current edition as adopted by the state..." That sentence is quoted exactly as the City's codified ordinance carries it. A companion section, 10-2-4, Future Codes Adopted, closes the loop: "All subsequent editions and/or supplements to the building and residential codes as adopted by the state legislature, hereby automatically are adopted by the city as they may become available." Blackfoot City Code Title 10, Chapter 2 is five sections long -- 10-2-1 Adopted, 10-2-2 Terms Defined, 10-2-3 Installation Of Manufactured Homes, 10-2-4 Future Codes Adopted and 10-2-5 Penalty -- and its own amendment content, read in full, does not touch the reroofing chapter or set the jurisdiction's own climatic design table in the codified text (that table is instead published separately on the Building & Safety Department's "Design Loads" webpage; see wind_design_criteria). Because the City adopts the edition "as adopted by the state" and automatically carries forward future state editions, Blackfoot moves when the Idaho Building Code Board moves. THE STATE FRAMEWORK: Idaho's residential code is set by the Idaho Building Code Board, not by the city. IDAPA 24.39.30.600.03 adopts the "International Residential Code, 2018 Edition ... Parts I, II, III, and IX of the 2018 Edition for one (1)- and two (2)-family dwellings," effective July 1, 2024, together with seventeen state amendments (none reaching Chapter 8 or 9); Idaho Code 39-4116(2) requires a local government that issues building permits and performs code enforcement to adopt the Idaho residential code parts I-III and IX by ordinance, together with the International Building Code and the 2018 Idaho energy conservation code. Idaho Code 39-4116(2) also bars a local jurisdiction from adopting provisions of a later IRC edition the Board has not adopted, so a city cannot be ahead of the state. Idaho Code 39-4116(6): "Permits shall be governed by the laws in effect at the time the permit application is received." The amlegal codification of Blackfoot's code states it is "current through: Ord. 2301, passed 8-4-2026."

Required — Neither the State of Idaho nor the City of Blackfoot modifies the model rule. IDAPA 24.39.30.600.03 -- the Idaho Building Code Board's complete list of amendments to the 2018 International Residential Code, read in full -- contains no amendment to Chapter 9, Roof Assemblies. Blackfoot City Code Title 10, Chapter 2, Building Code, read section by section, adopts the state building and residential codes with no amendment touching roof assemblies. The base 2018 IRC drip-edge requirement for asphalt shingle roofs (Section R905.2.8.5) therefore applies unmodified in Blackfoot. Confirm the flashing detail and the fastener spacing against the shingle manufacturer's printed instructions as well, which the code makes binding. About drip edge

Required — The City of Blackfoot's own Building & Safety Department publishes the ice barrier requirement directly, on its "Design Loads" page, separately from the codified ordinance: "Ice Barrier Underlayment 24 in (Required)." That page is the City's own published design-criteria table for the 2018 IRC's climatic and geographic design criteria (Table R301.2(1)), which the base code leaves for the adopting jurisdiction to fill in and which Blackfoot's own Title 10, Chapter 2 does not separately print in the codified text. Neither the State of Idaho's amendments to the 2018 IRC (IDAPA 24.39.30.600.03, read in full) nor Blackfoot's own building-code chapter (read in full) modifies or disclaims the base ice-barrier rule at Section R905.1.2. Confirm the 24-inch figure and the eave measurement point with the Building & Safety Department before you bid, since it is published on a department webpage rather than in the codified ordinance. About ice & water barrier

Not required — No impact-resistance mandate applies in Blackfoot. IDAPA 24.39.30.600.03 -- the State of Idaho's complete list of amendments to the 2018 International Residential Code, read in full -- contains no amendment to Chapter 9, Roof Assemblies, and no UL 2218, Class 4 or FM 4473 impact-rating reference anywhere in the rule. Blackfoot City Code Title 10, Building Regulations, was read in full across all four chapters, and it contains no UL 2218, Class 4, Class IV or FM 4473 reference and no hail provision. The City's own "Design Loads" page likewise prints only seismic, snow, wind, frost and ice-barrier figures -- no impact-rating column. Neither the state's nor the City's adopted code imposes an impact-resistant roof covering requirement. An insurance discount for impact-rated shingles, where a carrier offers one, is a matter between the homeowner and the insurer and is not a code requirement.

No dollar figure and no square-footage threshold has been established for roofing work in Blackfoot. City Code 10-2-1, Building and Residential Codes Adopted (read in full, along with the rest of Title 10, Chapter 2's five sections), adopts the state building and residential codes for "regulating the erection, construction, enlargement, alteration, repair, moving, removal, demolition, conversion, occupancy, equipment, use, height, area and maintenance of all buildings and structures within the jurisdiction of the city" and creates no permit-exempt work list, no size threshold and no repair carve-out of its own. The State of Idaho's only amendments to the base 2018 IRC's permit-exempt work list (IDAPA 24.39.30.600.03, read in full) are a dimension change to item 7 under the "Building" subheading (a 24-inch figure replaced with a four-foot figure) and the addition of item 11, "Flag poles" -- neither reaches roof coverings. Because neither the state amendment list nor the City's own adopting chapter creates a roofing-specific exemption, a re-roof in Blackfoot falls under the general permit requirement in City Code 10-2-1 rather than any stated exempt-work or minor-alteration threshold. Note separately that IDAPA 24.39.30.002.02's definition of "Minor Alteration" -- which includes "roof repairs involving installation of less than one hundred (100) square feet of new roof covering" -- is stated to apply "for the purpose of administering annual permits," a facility-level instrument for ongoing minor work, and is not a general residential permit exemption.

Take these from Blackfoot's own published table, not from a neighbouring city's. The City of Blackfoot Building & Safety Department's "Design Loads" page prints the City's own values directly, separately from the codified ordinance text: Seismic Design Category D; Ground Snow Load 50 psf; Roof Snow Load 35 psf (ground snow load times 0.7); Wind Load Exposure C, 90/105 mph with 3-second gust; Frost Depth 30 inches; Ice Barrier Underlayment 24 inches (Required); Elevation 4,488 feet. THE WIND FIGURE IS PRINTED AS TWO NUMBERS, and the page does not explain the difference: "90/105 w/3 sec gust." Match whichever figure your design method, engineering calculation or product listing actually asks for, and confirm the basis with the Building & Safety Department rather than guessing between them. Blackfoot City Code Title 10, Chapter 2, Building Code, read in full, contains no amendment to the codified 2018 IRC climatic and geographic design criteria table (Table R301.2(1)) of its own -- the Design Loads page is the City's only published source for these figures. The State of Idaho separately deletes the model code's wind-borne debris opening-protection section statewide: IDAPA 24.39.30.600.03(d) reads "Section R301.2.1.2 Protection of Openings. Delete." That is an opening (window and door) provision rather than a roofing one, and under Idaho Code 39-4116(4)(b) a local jurisdiction may not re-adopt a provision the Idaho Building Code Board has expressly rejected.

Neither the State of Idaho nor the City of Blackfoot modifies the model reroofing rule. IDAPA 24.39.30.600.03 -- the Idaho Building Code Board's complete list of seventeen amendments to the 2018 International Residential Code, read in full -- contains no amendment to Chapter 8 or Chapter 9. Blackfoot City Code Title 10, Building Regulations, was read in full across all four of its chapters (Chapter 1, Administrative Code and Building Department; Chapter 2, Building Code; Chapter 3, Property Maintenance Code; Chapter 4, Mechanical Code), and Chapter 2's own amendment list, read section by section (10-2-1 through 10-2-5), touches nothing beyond adopting the state building and residential codes, defining terms, addressing manufactured homes, floating future code editions, and setting a penalty. Nothing in it amends, deletes or excepts the reroofing section. Base-code rule, 2018 IRC Section R908.3.1.1 (Roof recover not allowed): a roof recover shall not be permitted where any of the following conditions occur: where the existing roof or roof covering is water soaked or has deteriorated to the point that it is not adequate as a base for additional roofing; where the existing roof covering is slate, clay, cement or asbestos-cement tile; or where the existing roof has two or more applications of any type of roof covering. One existing layer may be recovered; a second forces a full tear-off. A local Idaho amendment to this rule would be unusually visible: Idaho Code 39-4116(4)(d) allows a city or county to amend this part of the residential code only by ordinance, on a recorded finding that "good cause for building or life safety exists" and that the amendment is "reasonably necessary," after a public hearing noticed in the official newspaper with at least thirty days' written notice to the local chapters of the industry bodies identified in Idaho Code 39-4116(4)(d).

IDAPA 24.39.30.600.03 -- the State of Idaho's complete list of amendments to the 2018 International Residential Code, read in full -- contains no amendment to Chapter 8, Roof-Ceiling Construction, or Chapter 9, Roof Assemblies. Blackfoot City Code Title 10, Chapter 2, Building Code, read section by section (10-2-1 through 10-2-5), adopts the state building and residential codes and amends nothing beyond defining local terms, addressing manufactured homes and floating future code editions. The base 2018 IRC roof sheathing and decking requirements therefore apply unmodified in Blackfoot, along with the shingle manufacturer's printed installation instructions, which the code makes binding. One local number bears on the deck without being a sheathing rule: the City's Building & Safety Department publishes a ground snow load of 50 psf and a roof snow load of 35 psf (ground snow load times 0.7) on its own "Design Loads" page, so a deck and the framing under it here are carrying real load.

6.0% -- the Idaho state rate, with no local add-on. Idaho Code 63-3619 imposes the state sales tax "at the rate of six percent (6%)." Idaho's only local sales taxes are a resort-city local-option tax, which the Idaho State Tax Commission's own current list of participating cities (read in full, updated January 13, 2026) does not include Blackfoot in, and an auditorium-district tax, which the Commission states applies only to short-term lodging of 30 days or less and so never reaches roofing work. Idaho counties levy no sales tax at all, so Bingham County adds nothing. HOW A ROOF IS TAXED, which matters more than the rate: Idaho sales tax law treats contractors as the consumers (end users) of the goods they use, so the roofer pays the 6% on materials at the supply house and the homeowner's invoice carries no sales tax line, on materials or on labour, because the tax is absorbed into the bid rather than charged to the customer.