City of Boise - Planning and Development Services, Building Division

City of Boise, Idaho

city

150 N Capitol Blvd, Boise, ID 83702

Required

Required

Boise permits re-roofing under permit type 428, Residential Roofing, Siding and Windows, applied for online through the City's permitting and licensing system; the City states that "All building applications are submitted electronically." Permits that need no review are charged and issued automatically at application; where a review is required, fees are assessed afterwards and are due before the permit issues. Inspections are then scheduled by the applicant or contractor in the same system, and re-inspection fees may be charged for repeat trips when the work is not ready. TWO BOISE-SPECIFIC CONDITIONS TO CHECK BEFORE QUOTING. First, fire classification: the City's roofing application states that "Class A roof covering is required for all structures within the WUI Zone & foothills", and that roof coverings and siding installed in the hillside area or Wildland Urban Interface area "must be non-combustible as regulated by the City of Boise Fire Prevention Code." That is a fire rating (Class A, B or C), not a hail or impact rating, and the application asks the applicant to designate the class of roof covering being installed. Second, historic and design review: building permit requirements are the same inside a historic district, but the City states that many types of exterior work there require a Certificate of Appropriateness from Planning and Zoning, obtained before the building permit is applied for. The application also asks whether the property is in a floodplain, a hillside area or a design review zone. Appeals from a decision of the Building Official or the Fire Code Official are heard by the City's own Building Code Board.

LOCALLY ENACTED, ON A STATE-MANDATED EDITION. The City of Boise publishes its own currently adopted codes, "revised and updated to apply to projects submitted on or after January 1, 2021": the 2018 International Residential Code, "parts I through IV and IX", including Appendix Q (Tiny Houses) and Appendix S (Strawbale Construction). Alongside it Boise has adopted the 2018 International Building Code (with the mass timber provisions of the 2021 IBC), the 2018 International Existing Building Code, the 2018 International Energy Conservation Code, the 2018 International Fire Code, the 2017 Idaho State Plumbing Code and the 2023 National Electrical Code. The City directs readers to Title 9 of Boise City Code, Building Codes and Regulations, for the adopting text and its local amendments; the City notes that its local amendment language for structural and snow loading sits at IBC Sections 1605.2, 1605.3.1, 1608.1 and 1608.2. Boise also runs its own Building Code Board, which hears appeals of decisions by the Building Official or Fire Code Official and reviews code updates, ordinance updates and amendments before they go to City Council. 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 a list of state amendments; 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. Parts IV through VIII -- energy, mechanical, fuel gas, plumbing and electrical -- are not part of the Idaho residential code (Idaho Code 39-4109(1)(b)); roofing sits in Part III and is included. 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."

Not required — Sourced from Boise's own climatic and geographic design criteria, not inferred from climate. The City of Boise publishes its filled-in 2018 IRC Table R301.2(1) on its current-codes page, and the entry reads "ICE BARRIER UNDER LAYMENT REQUIRED h : NO", against the table's own footnote "In accordance with Sections R905.2.7, R905.4.3.1, R905.5.3.1, R905.6.3.1, R905.7.3.1 and R905.8.3.1, where there has been a history of local damage from the effects of ice damming." The rest of that table is worth having in front of you on a Boise roof: ground snow load 20 psf, with a design roof load of not less than a uniform snow load of 25 psf; weathering severe; frost line depth 24 inches; winter design temperature 10 degrees F; air freezing index 894; mean annual temperature 51.1 degrees F. Idaho's state rule does not answer the ice barrier question either way: IDAPA 24.39.30.600.03 amends nothing in Chapter 9 of the 2018 International Residential Code, and Table R301.2(1) is the one part of Part III that Idaho Code 39-4116(4)(c) leaves a city free to fill in and amend for local conditions. Nothing in the City's entry stops a shingle manufacturer's printed instructions, or a particular roof's exposure, from calling for eave protection anyway. About ice & water barrier

No minimum size and no dollar figure -- Boise draws a scope line instead. The City's own guide to residential construction lists "Re-roof an existing structure" among the work that requires a Building Permit, and neither that guide nor the City's roofing permit application states any square footage or dollar value below which a re-roof may go ahead without one. The line Boise does draw is between covering work and structural work. Permit 428 (Residential Roofing, Siding and Windows) "Each application allows for the replacement, repair or installation of new materials"; the application then states that "Structural modification are not allowed under this application and will require a separate permit (#406 Residential Additions/Alteration or #520 Commercial Major Tenant Improvement) and Plan Review approval", naming "replacement of roof trusses, interior roof drains or mechanical installations" among the structural modifications it means. Replacing roof sheathing stays inside the 428 permit -- the application asks whether the sheathing will be replaced and with what material -- but replacing trusses does not. The 428 application covers both an "alteration" and a "repair", so a partial repair and a full tear-off are applied for on the same form. A Boise permit application is incomplete until an Idaho contractor registration number is supplied or an exemption is declared.

Take these from the City's own table, which Boise publishes filled in. Boise's 2018 IRC Table R301.2(1) prints "WIND DESIGN SPEED d (mph): 90", with the qualifier "Wind speed from the basic wind speed map [Figure R301.2(5)A]" and "Wind exposure category shall be determined in accordance with Section R301.2.1.4"; "WIND DESIGN TOPOGRAPHIC EFFECTS k : NO"; and "SEISMIC DESIGN CATEGORY f : C". For roof loading the same table gives a ground snow load of 20 psf and states that the "Design roof load shall not be less than a uniform snow load of 25 psf". CHECK THE BASIS BEFORE YOU APPLY THE NUMBER. A nominal wind speed (the older allowable-stress basis) and an ultimate design wind speed are two different numbers for the same wind loading and are not interchangeable; confirm which basis your design method, engineering or product listing expects before using the City's 90 mph figure. Note also that the State of Idaho 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. Boise separately publishes commercial wind criteria on the IBC track, using IBC Figures 1609.3(1) to 1609.3(4) with the exposure category per IBC Section 1609.4 -- do not carry a commercial figure onto a one- or two-family dwelling.

Two layers maximum, and an overlay is permitted only over a single existing layer. The City of Boise states the rule on its own roofing permit application, permit type 428 (Residential Roofing, Siding and Windows): "City Code allows for a maximum of two layers of roofing material. Overlays are limited to roofs with a single layer." The same application repeats it in its closing conditions: "Roofing materials are limited to a maximum of 2 layers." So a Boise roof already carrying two coverings must be torn off, and one carrying a single covering may be recovered once. That matches the code Boise has adopted, and neither government has moved it: the State of Idaho's complete list of amendments to the 2018 International Residential Code, IDAPA 24.39.30.600.03, seventeen items read in full, contains no amendment to Chapter 9, Roof Assemblies. Base-code rule, 2018 IRC Section R908.3.1.1 (Roof recover not allowed): a roof recover is not permitted where the existing roof or covering is water-soaked or has deteriorated to the point that it is not an adequate base for additional roofing; where the existing roof covering is slate, clay, cement or asbestos-cement tile; or where the existing roof already has two or more applications of any type of roof covering. 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 listed in Idaho Code 39-4109(5).

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 has only two kinds of local sales tax, and neither applies here: a resort-city local-option tax, which Idaho Code 50-1044 confines to resort cities "with a population not in excess of ten thousand (10,000)" and which the Idaho State Tax Commission's own list of participating cities does not include this jurisdiction in; and an auditorium-district tax, which the Tax Commission states "can charge a local sales tax only for short-term lodging (30 days or less)" and so never reaches roofing work. Boise lies within the Greater Boise Auditorium District, but that district's tax applies only to short-term lodging and does not change the rate on a roof. Idaho counties levy no sales tax at all. HOW A ROOF IS TAXED, which matters more than the rate: the Tax Commission's contractor guidance states that "Idaho sales tax law says contractors are the consumers (end users) of all the goods they use. As a result, they must pay sales tax on all purchases", and it names roofers among the contractors it covers. The roofer pays the 6% on materials at the supply house; the homeowner's invoice carries no sales tax line at all, on materials or on labour, because "a contractor doesn't charge sales tax to the customer" and the tax is absorbed into the bid. The Commission adds that "if sales tax is charged on the bill, the customer can refuse to pay it." A customer's own sales-tax exemption does not carry over to the contractor.