The Roofing Book

Permitting Authorities / City of Derby - Building Department

Do you need a permit to replace a roof in Derby, CT?

Adopted code

City of Derby - Building Department

The City of Derby Building Department, at Derby City Hall, 1 Elizabeth Street, takes building permit applications for work in Derby through an online permit system. The Connecticut State Building Code applies in Derby as it does in every Connecticut town and city. This listing covers the office's contact details and the rules state law sets for every Connecticut town; it does not cover Derby's own permit rules.

Roof code checklist: Derby, CT

ItemAnswerCode citeSourceVerified
Permit to replace a roofNot published
Repair permit thresholdNot published
Layer limit / roof-overPublishedR908.3.1.12022-csbc-final.pdf2026-10-09
Deck & sheathingPublishedR905.2.12022-csbc-final.pdf2026-10-09
Drip edgeYesR905.2.8.52022-csbc-final.pdf2026-10-09
Ice & water shieldYesR905.1.22022-csbc-final.pdf2026-10-09
Mid-roof inspectionNot published
Impact-resistant (Class 4) roofingNo2022-csbc-final.pdf2026-10-09
Wind design criteriaPublishedR301.2.12022-csbc-final.pdf2026-10-09
Adopted codePublished2022-csbc-final.pdf2026-10-09
Contractor license / registrationYescga.ct.gov2026-10-09
Sales & use taxPublishedportal.ct.gov2026-10-09

Each row comes from the sourced record on this page; full wording is in the table below. "Not published" means no official source for that item was found when the record was last verified.

Jurisdiction
City of Derby, Connecticut
Jurisdiction type
city
Address
1 Elizabeth Street, Derby, CT 06418
Contact
  • url: https://www.derbyct.gov/building-department
  • phone: 203-736-1481
Permit portal
Permit portal
Contractor registration required
Required
Adopted code
The 2021 International Residential Code, as amended by the State in the 2022 Connecticut State Building Code, which "shall apply to all work for which a permit application was made on or after the date of adoption"; the Department of Administrative Services applies it to projects with permit applications filed from October 1, 2022. Connecticut has one building code for every municipality: "The State Building Code, including any amendment to said code adopted by the State Building Inspector and Codes and Standards Committee, shall be the building code for all towns, cities and boroughs" (C.G.S. 29-253(a)). A town does not adopt or amend the code itself. It "may propose amendments to the State Building Code," and an amendment may be restricted to one municipality only "where it is alleged and established that conditions exist within a municipality which are not generally found within other municipalities"; each amendment is adopted by the State (C.G.S. 29-254(a)). The residential portion makes no town-specific change to the roofing rules; its only town-by-town content is Appendix AY, the State's table of wind speeds and snow loads for each municipality. A building official's own policies "shall not have the effect of waiving requirements specifically provided for in this code, nor shall they have the effect of establishing requirements in excess of those set forth in this code" (CT IRC R104.1). The State's changes to the roof chapter add one rule: "A minimum 4-inch-wide (102 mm) strip of self-adhering polymer-modified bitumen membrane complying with ASTM D1970, installed in accordance with the manufacturer's instructions for the deck material, shall be applied over all joints in the roof decking" (CT IRC R905.1.1). The section's exceptions allow self-adhering ASTM D1970 underlayment instead, and drop the strips "for roofs sheathed with lumber having a nominal width of less than 3 feet." Everything above is Connecticut state law, the same in every municipality. In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system.
Drip edge
Required — Required on shingle roofs throughout Connecticut. The State adopts the 2021 International Residential Code without changing its drip edge rule, Section R905.2.8.5: "A drip edge shall be provided at eaves and rake edges of shingle roofs." Segments overlap by at least 2 inches, the drip edge extends at least 1/4 inch below the roof sheathing and at least 2 inches back onto the deck, it is fastened at no more than 12 inches on center, and "Underlayment shall be installed over the drip edge along eaves and under the drip edge along rake edges." A reroof is held to the same chapter: "Materials and methods of application used for recovering or replacing an existing roof covering shall comply with the requirements of Chapter 9" (R908.1). In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system. About drip edge
Ice & water shield
Required — Required statewide. Connecticut replaces the model code's climatic table with its own Table R301.2, filled in once for the whole state, and its ice barrier underlayment entry is "YES." Under Section R905.1.2 an ice barrier "shall be installed for asphalt shingles, metal roof shingles, mineral-surfaced roll roofing, slate and slate-type shingles, wood shingles and wood shakes," consisting of "not fewer than two layers of underlayment cemented together, or a self-adhering polymer-modified bitumen sheet," extending "from the lowest edges of all roof surfaces to a point not less than 24 inches (610 mm) inside the exterior wall line of the building," and on roofs of 8:12 slope or steeper "not less than 36 inches (914 mm) measured along the roof slope from the eave edge of the building." Detached accessory structures with no conditioned floor area are excepted. On a tear-off, an ice barrier membrane adhered to the deck may stay in place and be covered with an additional layer (R908.3, Exception). In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system. About ice & water barrier
Impact-resistant roofing
Not required — No impact-resistance requirement under state law. The 2022 Connecticut State Building Code's amendments contain no hail or impact rule (no mention of UL 2218, Class 4 or hail anywhere in the State's amendment document), and the roof assemblies chapter of the International Residential Code it adopts has no UL 2218, Class 4 or hail-impact requirement for roof coverings. The State Building Code is the building code for every town, city and borough (C.G.S. 29-253(a)), and the code makes no town-specific roofing change. An owner may still choose an impact-rated roof covering. In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system.
Wind design criteria
Set by the State for each municipality. Connecticut's residential code requires construction "in accordance with the wind provisions of this code using the ultimate design wind speed in Appendix AY" (CT IRC R301.2.1), and Appendix AY lists the wind speed for every municipality. For Derby, Appendix AY gives an ultimate design wind speed (Vult) of 120 mph, a nominal design wind speed (Vasd) of 93 mph, and lists it in the hurricane-prone region. The exposure category is decided site by site (Table R301.2, footnote b; R301.2.1.4). Asphalt shingles must be tested to ASTM D7158, or to ASTM D3161 if outside D7158's scope, and labelled with the class Table R905.2.4.1 requires for that wind speed (R905.2.4.1); for an ultimate design wind speed above 116 mph and up to 129 mph the table requires D7158 Class G or H, or D3161 Class A, D or F. Where a project is a substantial improvement on a site with wind Exposure D, uncovered structural elements must be improved to meet the wind design criteria (CT IRC R105.3.1.1.1). These are wind ratings, not fire or impact ratings. Everything above is Connecticut state law. In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system.
Roof layer limit / recover
Two layers at most. Connecticut adopts the 2021 International Residential Code without changing its reroofing section, R908 (the State's amendments to the roof chapter change only R905.1.1 and Table R905.2.4.1). Section R908.3.1.1 says "A roof recover shall not be permitted where any of the following conditions occur," and the third condition is "Where the existing roof has two or more applications of any type of roof covering." So one existing layer may be covered once, and a roof that already has two layers is torn off to the deck: "Roof replacement shall include the removal of existing layers of roof coverings down to the roof deck" (R908.3). The same section also bars a recover "Where the existing roof or roof covering is water soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing" and "Where the existing roof covering is slate, clay, cement or asbestos-cement tile." The State Building Code is the building code for every town, city and borough (C.G.S. 29-253(a)), so this rule is the same in every municipality. In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system.
Deck & sheathing requirements
State rules, the same in every municipality. Connecticut adopts the 2021 International Residential Code without changing Section R803, Roof Sheathing (the State's changes to Chapter 8 are to rafter sizing and truss limits). Lumber roof sheathing follows Table R803.1: over rafters or beams 24 inches apart it must be at least 5/8 inch net thick. Wood structural panels "shall be identified for grade, bond classification and performance category by a grade mark or certificate of inspection issued by an approved agency," and their spans "shall not exceed the values set forth in Table R503.2.1.1(1) or APA E30." For shingles, "Asphalt shingles shall be fastened to solidly sheathed decks" (R905.2.1), and on any reroof "The structural roof components shall be capable of supporting the roof covering system and the material and equipment loads that will be encountered during installation of the roof covering system" (R908.2). Connecticut adds a rule at the deck joints: "A minimum 4-inch-wide (102 mm) strip of self-adhering polymer-modified bitumen membrane complying with ASTM D1970, installed in accordance with the manufacturer's instructions for the deck material, shall be applied over all joints in the roof decking," with the underlayment then "applied over the entire roof and over the 4-inch-wide (102 mm) membrane strips" (CT IRC R905.1.1). The strips are not required where self-adhering ASTM D1970 underlayment is used as the underlayment, or "for roofs sheathed with lumber having a nominal width of less than 3 feet." In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system.
Sales & use tax
6.35% Connecticut sales and use tax, the same in every town: the Department of Revenue Services says "There are no additional sales taxes imposed by local jurisdictions in Connecticut." The rate is set by C.G.S. 12-408(1)(A) ("six and thirty-five-hundredths per cent"). On a reroof of an owner-occupied home the roofer pays the tax on materials and does not charge tax on the labour. The Department's Building Contractors' Guide (IP 2006(35)) says of roofing on existing real property: "The roofing contractor pays tax on all purchases of materials that will be incorporated into the job," and "The roofing contractor does not charge tax when installing the roofing on: Owner-occupied residential property," which it defines as property that "Is used exclusively for residential purposes," "Consists of one to three dwelling units," and where "The owner resides or will reside at the property upon completion of the work." Roofing on existing commercial, industrial or income-producing property is a taxable service: the statute taxes "Services to industrial, commercial or income-producing real property," and excludes from income-producing property one "used exclusively for residential purposes in which the owner resides and which contains no more than three dwelling units" (C.G.S. 12-407(a)(37)(I)). Everything above is Connecticut state law, the same in every municipality. In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system.

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Sources

Roofing questions: Derby, CT

Is ice & water shield required in Derby, CT?

Yes. Required statewide. Connecticut replaces the model code's climatic table with its own Table R301.2, filled in once for the whole state, and its ice barrier underlayment entry is "YES." Under Section R905.1.2 an ice barrier "shall be installed for asphalt shingles, metal roof shingles, mineral-surfaced roll roofing, slate and slate-type shingles, wood shingles and wood shakes," consisting of "not fewer than two layers of underlayment cemented together, or a self-adhering polymer-modified bitumen sheet," extending "from the lowest edges of all roof surfaces to a point not less than 24 inches (610 mm) inside the exterior wall line of the building," and on roofs of 8:12 slope or steeper "not less than 36 inches (914 mm) measured along the roof slope from the eave edge of the building." Detached accessory structures with no conditioned floor area are excepted. On a tear-off, an ice barrier membrane adhered to the deck may stay in place and be covered with an additional layer (R908.3, Exception). In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system.

Is drip edge required in Derby, CT?

Yes. Required on shingle roofs throughout Connecticut. The State adopts the 2021 International Residential Code without changing its drip edge rule, Section R905.2.8.5: "A drip edge shall be provided at eaves and rake edges of shingle roofs." Segments overlap by at least 2 inches, the drip edge extends at least 1/4 inch below the roof sheathing and at least 2 inches back onto the deck, it is fastened at no more than 12 inches on center, and "Underlayment shall be installed over the drip edge along eaves and under the drip edge along rake edges." A reroof is held to the same chapter: "Materials and methods of application used for recovering or replacing an existing roof covering shall comply with the requirements of Chapter 9" (R908.1). In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system.

Can you roof over an existing roof in Derby, CT?

Two layers at most. Connecticut adopts the 2021 International Residential Code without changing its reroofing section, R908 (the State's amendments to the roof chapter change only R905.1.1 and Table R905.2.4.1). Section R908.3.1.1 says "A roof recover shall not be permitted where any of the following conditions occur," and the third condition is "Where the existing roof has two or more applications of any type of roof covering." So one existing layer may be covered once, and a roof that already has two layers is torn off to the deck: "Roof replacement shall include the removal of existing layers of roof coverings down to the roof deck" (R908.3). The same section also bars a recover "Where the existing roof or roof covering is water soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing" and "Where the existing roof covering is slate, clay, cement or asbestos-cement tile." The State Building Code is the building code for every town, city and borough (C.G.S. 29-253(a)), so this rule is the same in every municipality. In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system.

Do roofing contractors need a license or registration in Derby, CT?

Yes.

What building code does Derby, CT use?

The 2021 International Residential Code, as amended by the State in the 2022 Connecticut State Building Code, which "shall apply to all work for which a permit application was made on or after the date of adoption"; the Department of Administrative Services applies it to projects with permit applications filed from October 1, 2022. Connecticut has one building code for every municipality: "The State Building Code, including any amendment to said code adopted by the State Building Inspector and Codes and Standards Committee, shall be the building code for all towns, cities and boroughs" (C.G.S. 29-253(a)). A town does not adopt or amend the code itself. It "may propose amendments to the State Building Code," and an amendment may be restricted to one municipality only "where it is alleged and established that conditions exist within a municipality which are not generally found within other municipalities"; each amendment is adopted by the State (C.G.S. 29-254(a)). The residential portion makes no town-specific change to the roofing rules; its only town-by-town content is Appendix AY, the State's table of wind speeds and snow loads for each municipality. A building official's own policies "shall not have the effect of waiving requirements specifically provided for in this code, nor shall they have the effect of establishing requirements in excess of those set forth in this code" (CT IRC R104.1). The State's changes to the roof chapter add one rule: "A minimum 4-inch-wide (102 mm) strip of self-adhering polymer-modified bitumen membrane complying with ASTM D1970, installed in accordance with the manufacturer's instructions for the deck material, shall be applied over all joints in the roof decking" (CT IRC R905.1.1). The section's exceptions allow self-adhering ASTM D1970 underlayment instead, and drop the strips "for roofs sheathed with lumber having a nominal width of less than 3 feet." Everything above is Connecticut state law, the same in every municipality. In Derby, the City Building Department, which has a Building Official, takes building permit applications through an online permit system.