Butte-Silver Bow, Montana - Building & Code Enforcement

City and County of Butte-Silver Bow, Montana

city

155 W. Granite St., Room 108, Butte, MT 59701

Required

Required

2021 International Residential Code with Appendix Q, as amended by ARM 24.301.154, adopted by Butte-Silver Bow Municipal Code 15.04.075: "There is adopted by the Council of Commissioners for the purpose of establishing rules and regulations for the construction, alteration, movement, enlargement, replacement, repair, equipment, use and occupancy, location, removal and demolition of detached one-and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress and their accessory structures... that certain code known as the International Residential Code 2021 Edition." That section was last amended by Ord. No. 2022-12, Sec. 3, adopted 9-21-2022. A second, independent applicability clause, Municipal Code 15.04.015, extends "the codes set forth in Title 15" to "all buildings within the building code enforcement area of Butte-Silver Bow County which is the entire area of the city-county, including that area within the town of Walkerville, including, but not limited to, residential buildings containing less than five dwellings units," citing "Section 50-60-102(l)(a), MCA" as enacted (the correct statutory cite is 50-60-102(1)(a); the ordinance's own text is quoted as it reads, without silent correction). Either clause independently satisfies Montana's requirement that a local body make the state building code specifically applicable to residential buildings under five dwelling units before the state code reaches a house (ARM 24.301.201(1), MCA 50-60-102(1)(a)). The county's own amendment chapter (Municipal Code 15.04.030 through 15.04.090, all read in full) touches only permit submittal, fee, and administrative sections; it amends nothing in the IRC's Chapter 9 roofing provisions. Separately, Municipal Code 15.04.010 adopts the 2021 International Building Code with Appendix B and Appendix C, and the 2021 International Swimming Pool & Spa Code, for non-dwelling structures.

Required — Montana's amended 2021 IRC makes ice-barrier underlayment mandatory statewide, not only where a history of ice damming is shown. ARM 24.301.154(23) amends Section R905.1.2 by deleting the model code's geographic trigger, "areas where there has been a history of ice forming along the eaves causing a backup of water as designated in Table R301.2," and inserting "the State of Montana." That state amendment reaches a house here only because Butte-Silver Bow's own legislative body has expressly extended the code to one- and two-family dwellings: Municipal Code 15.04.075 adopts the 2021 IRC by name specifically for "detached one-and two-family dwellings and townhouses," rather than merely inheriting dwelling coverage from a general building-code adoption. The county's own local amendment chapter does not touch Section R905 or any other Chapter 9 roofing provision, so the statewide ice-barrier rule applies here unmodified. About ice & water barrier

Municipal Code 15.04.040 amends the base International Building Code's permit-exemption section (Section 105.2) by adding exactly two local exemptions: "14. Re-siding on existing residential units" and "15. Interior residential single family dwelling remodel as long as no structural alterations." Neither item names roofing or roof covering replacement, so re-roofing is not added to the exempt list by local amendment. The Office's own building-permit fee table (Municipal Code 15.04.060, Table No. 1-A) sets a fee starting at $12.50 for any valuation from $1.00 to $500.00, with no dollar floor below which a permit is not required; that table applies to roofing work because Section 109.2, as locally amended, defines permit valuation to include "all finish work, painting, roofing, electrical, plumbing, heating, air conditioning" and other trade work. The county's own May 2026 monthly permit report lists roofing permits (prefix "ROOF-26-...") issued at valuations as low as $3,400, which is consistent with no local minimum threshold for a roofing permit. The base IRC's own Section 105.2 exemption text (as it reads before the two local additions) has not been read for this record and is not quoted here.

The Building & Code Enforcement Office's own "Local Building Design Standards" sheet sets the design wind speed at 115 mph, ground snow load at 38 psf, seismic design category D, exposure category "Severe" weathering, frost depth 42 inches, and an air freezing index of 2,500. Montana's own IRC amendment (ARM 24.301.154(5)) leaves the ground snow load itself to be "determined by the building official" rather than fixing a statewide figure, and supplies no wind speed at all, so these figures are the jurisdiction's own published values rather than a state table entry.

Municipal Code 15.04.075 expressly extends the 2021 IRC to "detached one-and two-family dwellings and townhouses," which is the local act Montana law requires before the state-amended IRC reaches a house here (MCA 50-60-102(1)(a); ARM 24.301.201(1)). Neither Montana's own IRC amendment packet (ARM 24.301.154, read in full: zero occurrences of "R908," "Chapter 9," or "shingle") nor the county's own local amendment chapter (Municipal Code 15.04.030 through 15.04.090, read in full) amends the reroofing section. This record omits a classification key pending a corpus-wide ruling on whether that classification may be set at all where the local building instrument, though read and confirmed silent on the point, was read for this record rather than by the jurisdiction's own author (open docket item at the time of writing).

Municipal Code 15.04.075 expressly extends the 2021 IRC to "detached one-and two-family dwellings and townhouses," which is the local act Montana law requires before the state-amended IRC reaches a house here (MCA 50-60-102(1)(a); ARM 24.301.201(1)). Neither Montana's own IRC amendment packet (ARM 24.301.154, read in full) nor the county's own local amendment chapter (Municipal Code 15.04.030 through 15.04.090, read in full) amends anything in Chapter 8, so the base 2021 IRC roof sheathing provisions (Section R803) apply unmodified here.

Montana has no general state or local sales tax. The Department of Revenue states plainly: "Montana does not have a general-use sales tax." A residential reroof in Butte-Silver Bow carries no sales tax on materials or labor. Butte-Silver Bow is not one of Montana's ten statutorily designated resort communities (Red Lodge, Virginia City, West Yellowstone, Whitefish, Big Sky, Cooke City, Craig, Gardiner, St Regis, Wolf Creek), so the local resort tax those communities may levy (MCA 7-6-1503, up to 3%, statutorily up to 4% since 2025) does not apply here in any event, and that tax reaches only lodging, restaurants, alcohol-serving establishments, and destination recreational facilities, not a roofing contract. A separate 1% gross receipts licence fee applies only to public contracts exceeding $80,000 (MCA 15-50-101(3)(a)) and does not reach an ordinary residential reroof.