City of Twin Falls - Building Safety Department

City of Twin Falls, Idaho

city

203 Main Avenue East, Twin Falls, ID 83301

Not required

Required

Residential building permits can be applied for online through the City's Building Permit Portal, and the Building Safety Department also takes applications in person at 203 Main Avenue East. Inspections are requested through the same portal or by phone: building inspections 208-735-7333, the Building Department office 208-735-7238, plumbing 208-735-7299, mechanical 208-735-7289 and electrical 208-735-7235. The Department states that building and trade inspections scheduled through the portal by 7:00 a.m. are same-day, that a re-inspection fee of $50.00 is charged only where the same issue fails more than once and must be paid before the re-inspection is scheduled, and that a certificate of occupancy can take up to three business days to process. Published residential plan review timelines run about two weeks for a new single-family home and about two weeks for fences, decks and pools. Building permit fees are assessed on declared project valuation, and the City's fee schedule tells an applicant to declare "the total value of all construction work for which the permit is issued (including overhead and profit), as well as finished work, painting, roofing, mechanical, electrical, plumbing" and other permanent equipment. The Department's own standing warning, in its words: "NO WORK SHALL BE DONE UNTIL PERMITS ARE ISSUED."

LOCALLY ENACTED, ON A STATE-MANDATED EDITION. The City of Twin Falls publishes its own locally-adopted residential codes on the Building Safety Department's residential design criteria page for one- and two-family dwellings and townhouses: the "2018 International Residential Code, Parts I-VI and IX, appendices A, B and G (with State amendments)", alongside the 2018 International Energy Conservation Code (with Idaho State amendments), the 2023 National Electrical Code and the 2017 Idaho State Plumbing Code. Note that the City lists more parts of the IRC than the State of Idaho adopts; roofing sits in Part III, which both include. Twin Falls has also written the state rule on which edition governs a job into its own policy, signed by the Building Official on November 26, 2024: "As per Idaho Code Section 39-4116, building permits shall be governed by the codes in effect at the time the permit application is received. The effective code on the application receipt date will guide the project to completion, unaffected by any updates or changes to the codes that occur after the application date." 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 the City of Twin Falls' own published design criteria, not inferred from climate. The Building Safety Department's residential design criteria for one- and two-family dwellings and townhouses print "Water and Ice Shield: NO (Must follow roof manufacture's installation requirements for underlayment)". So the City requires no ice barrier underlayment, and the underlayment actually used must go down to the roofing manufacturer's printed instructions, which the code makes binding. The same sheet gives the local conditions behind that call: ground snow load 15 psf, frost depth 24 inches, climate zone 5B, winter heating design temperature 2 degrees, and "Subject to damage from weathering: Severe". Idaho's state rule does not answer this question -- 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 or county free to fill in and amend for local conditions. About ice & water barrier

Not required — No mid-roof inspection in Twin Falls, on two independent grounds. First, the City of Twin Falls Building Safety Department publishes its residential inspection sequence -- the "RESIDENTIAL INSPECTION SCHEDULING PROCESS", nine numbered stages running footing and setback, foundation, shear, mechanical/electrical/plumbing rough, framing, insulation, gypsum, mechanical/electrical/plumbing final, and final building -- and not one of the nine inspects a roof in progress. Second, there is no reroofing inspection to schedule because the City requires no permit for a reroof. Where a permit does issue, for a new roof structure or new trusses, the roof framing is seen at the framing inspection, and the City asks that truss engineering be on site for it and that the mechanical, electrical and plumbing rough inspections be approved first.

No permit for a reroof, and the line Twin Falls draws is scope, not size and not dollar value. The City of Twin Falls Building Safety Department states it on its own Permit Requirements page, in the list headed "Work requiring permits" under the page heading "Requirements": "Most alterations, including new built-up roofs/trusses, new windows, etc., require permits; a permit is not required for things such as interior wall paint, reroofing, or replacing the carpet." Read both halves of that sentence before assuming a job is exempt. Replacing a roof covering needs no permit at any size and any value; "new built-up roofs/trusses" -- a new roof structure, or new or replacement trusses -- does. So a tear-off that turns into framing or truss work moves back into permit territory, and the City states no square footage and no dollar figure anywhere in that sentence. The City writes no exempt-work list of its own and takes the code's instead: the same page states that "The City of Twin Falls will use section 105.2 of the currently adopted International Residential Code (IRC) and International Building Code (IBC) for work that is exempt from permits", and warns that "Exemption from permit requirements shall not be deemed to grant authorization for any work to be done in any manner in violation of the provisions of the City, State or other adopted codes." That warning is the important half: the roof still has to be built to the adopted code, inspected or not. Consistent with the exemption, the Department publishes no reroofing permit application -- its residential applications are the new home, enclosed addition, not-enclosed addition, interior remodel and detached accessory forms. Where the scope is uncertain the Department asks for the call: "If you are uncertain if the work you are about to begin requires a permit, please contact the Building Safety Department by calling (208) 735-7238 before construction is started."

Wind speed 115 mph, which the City states as gust velocity. The City of Twin Falls Building Safety Department publishes these residential design criteria for one- and two-family dwellings and townhouses, each figure given here under the City's own label: "Wind Speed: 115 mph gust velocity"; wind exposure given as "B" with "C" in some areas; seismic design category given as "B", noted "IRC Structures Only-See Commercial Design Criteria for IBC"; "Elevation: 4,154 ft. at Twin Falls Airport"; "Frost Depth: 24 inches"; "Climate Zone: 5B"; "Presumed Soil Bearing Pressure: 1500 psf without soils investigation"; and "Snow load: Ground snow load 15 psf. Minimum uniformly distributed design roof load shall be 25 psf per local ordinance". Two of those bear directly on a roof. The 25 psf minimum design roof load is a local figure the City attributes to its own ordinance and it is the number to design to, not the 15 psf ground snow load. And wind exposure is site-specific here: the City gives B generally and C in some areas, so establish the exposure for the actual address. Beyond the words "gust velocity" the City does not print whether its 115 mph is a nominal or an ultimate design wind speed, and those are different numbers for the same loading, so confirm the basis with the Building Safety Department rather than converting it. One state fact belongs here and it is a wind fact: 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 provision for windows and doors 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.

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 in Twin Falls: 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 whose participating cities the Idaho State Tax Commission lists by name without Twin Falls among them; 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. Idaho counties levy no sales tax at all, so nothing is added for Twin Falls County. 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.