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Bathroom, Kitchen and Home Remodeling in Portsmouth, NH
About 38% of Portsmouth's homes were built in 1939 or earlier, and the median year built is 1954, so a remodel here is usually old-house work under city rules that reach even repairs over $3,000. Call (978) 951-4644 or use the form. A person reads every request and replies with what happens next.
- Free for homeowners
- City and state remodeling rules on this page
- The South End to Sagamore Creek
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Remodeling in Portsmouth
What are you planning?
Kitchen Remodeling
New layouts, cabinets and counters, with licensed trades for any plumbing, gas and electrical work.
Bathroom Remodeling
Tub-to-shower conversions, full gut renovations and added bathrooms, permitted the way your town requires.
Additions & Whole-Home
Additions, dormers, second stories and whole-house renovations, with the structural permits and zoning they bring.
Attic & Basement Finishing
Turning an attic or a dry basement into living space, with the building department involved from the start.
Not sure where to start?
(978) 951-4644Tell us whether the house is in the Historic District, near the water or on a small lot, and we'll help you sort out what the city will want to see first.
Permits
Remodeling permits in Portsmouth
The Inspection Department is in City Hall at 1 Junkins Ave, open Monday 8 to 6, Tuesday to Thursday 8 to 4:30 and Friday 8 to 1, and takes applications through the city's Viewpoint permitting portal (Inspection Department).
What needs a permit. The department's FAQ says "New construction and general renovation work requires the issuance of a building permit," including "Creating new rooms or spaces within a structure" and structural changes or repairs. Ordinary repairs such as painting, flooring, trim, insulating and window, door or siding repair are exempt, but a permit is needed "When the total cost of ordinary repair work exceeds three thousand dollars ($3,000)," and ordinary repair never includes altering a structural beam or required egress. Interior renovations to a single-family home skip zoning review; exterior changes in the Historic District need a separate HDC application that adds at least a month.
Fees. The city's building permit fee page, marked "Updated 18 OCT 23," lists alterations and renovations at $8 per $1,000 of renovation cost, new one- and two-family homes at $8 per $1,000 with a $75 minimum, demolition at $75 up to 2,000 square feet and re-inspections at $100, with fees rounded up to the nearest $5. Work done without a permit costs 200% of the fee or $300, whichever is greater (the regular fee plus $300 when the fee tops $300). The city's FY27 fee packet keeps mechanical, plumbing and gas fees unchanged from FY26, including gas piping at $30 per meter and a $75 residential minimum; residential electrical permits also carry a $75 minimum.
Inspections. Request them on the portal or by phone with the permit number, address and inspection type; "ALL CANCELATIONS AND RESCHEDULING MUST BE CALLED IN!" (scheduling inspections).
- Building permits
- Inspection Department, City Hall, 1 Junkins Ave
- Apply online
- Viewpoint portal
- Renovations
- $8 per $1,000 of renovation cost (fee page dated Oct 18, 2023)
- Repairs
- Permit needed once ordinary repairs exceed $3,000
- No permit
- 200% of the fee or $300, whichever is greater
- Historic District
- Separate HDC application for exterior changes
State rules. New Hampshire doesn't license general remodelers ("contractors do not need to be licensed," says the Attorney General), so ask for references, suppliers and proof of insurance, and sign a written contract with scope, materials, total price and payment schedule before any work or payment (NH Attorney General). Plumbers, gas fitters and electricians are licensed (OPLC; RSA 319-C). On a home contract over $5,000 the contractor must hand you the RSA 359-G notice, and a homeowner must give 60 days' written notice before suing over a defect (RSA 359-G). Permits are issued locally under the State Building Code (RSA 155-A:2), which moved to the 2024 codes on July 1, 2026, with either code set accepted through December 31, 2026 (state code summary).
Last verified November 2026. Fees, restrictions and deadlines on this page are due for re-checking by July 2027. New England Remodeling Pros is a referral service. We don't do the remodeling ourselves; the contractor you hire, or you as the owner, files the permits.
Zoning
Adding on in Portsmouth
Small lots, short setbacks. The Zoning Ordinance, as amended through October 26, 2026, sets the dimensions in its section 10.521 table:
- GRA: 7,500 sq ft lots; front 15 ft, side 10 ft, rear 20 ft; building coverage 25%, open space 30%.
- GRB: 5,000 sq ft lots; front 5 ft, side 10 ft, rear 25 ft; coverage 30%, open space 25%.
- GRC: 3,500 sq ft lots; front 5 ft, side 10 ft, rear 20 ft; coverage 35%, open space 20%.
- SRA and SRB: 1 acre and 15,000 sq ft lots, with coverage of 10% and 20%.
Nonconforming houses. A nonconforming building "may not be extended, reconstructed or enlarged unless such extension, reconstruction or enlargement conforms to all the regulations of the district" (section 10.321). The ordinance does allow the minimum changes needed for egress even if they expand a nonconformity, and Historic District work must also meet the HDC rules.
Accessory dwelling units. State law requires one ADU, attached or detached, to be allowed by right wherever single-family homes are (RSA 674:72; RSA 674:73). Portsmouth's 2025 ADU Homeowner's Handbook caps an attached ADU at 750 square feet of gross living space and a detached one at 600 square feet with administrative approval or up to 750 with a Planning Board conditional use permit. The owner must live in one unit, both stay in single ownership, one off-street space is required and rentals under 30 days aren't allowed. Approval comes by Planning Board conditional use permit or administratively from the Planning and Sustainability Director, and an interior conversion with no exterior change is "usually allowed as-of-right." The conditions letter is recorded at the Registry of Deeds before the building permit (permit flow chart).
Wetlands and water. Wetlands over 10,000 square feet, including most tidal areas, carry a 100-foot buffer where "New construction, ground disturbance and fill or removal of soil are not allowed" without a city conditional use permit (wetland buffer). The Floodplain District covers FEMA flood areas plus city "extended flood hazard areas" (floodplain regulations). In the protected shoreland, construction or excavation also needs an NHDES shoreland permit (RSA 483-B:5-b), and footings need a free Dig Safe ticket 72 hours ahead, excluding weekends and legal holidays (Dig Safe, 811).
Old houses
Old houses and historic review in Portsmouth
Historic District. The Historic District Commission issues a Certificate of Approval for "certain exterior changes to buildings and structures located within the Historic District," and usually meets on the first Wednesday of the month. The Inspection Department says an HDC application adds at least an extra month to the review process. The Portsmouth Downtown Historic District listed on the National Register in June 2017 is a separate designation (historic preservation).
Citywide demolition review. Outside the district too, the Demolition Ordinance covers "privately-owned buildings and structures of historic, architectural and cultural value," with "a minimum 30-day review period" before the Demolition Committee, and demolishing "a portion of a building or structure" needs a demolition permit as well. Exempt are demolitions with an HDC Certificate of Approval or tied to a Planning Board or Board of Adjustment hearing, dangerous buildings, minor items such as chimneys, decks, porches and steps outside the Historic District, and partial roof removal for dormers or skylights outside the district.
Lead paint. With so many houses built before 1978, lead rules apply to most remodels here: anyone paid to disturb painted surfaces must be EPA lead-safe certified, "even sole proprietorships," and window replacement is always covered (EPA RRP; EPA contractor rules). EPA runs the program directly in New Hampshire.
Portsmouth's homes
Old houses, many of them multifamily
The city's 2014 Housing Existing Conditions report, prepared for the 2015 Master Plan from ACS 2008–2012 data, found about 38% of homes built in 1939 or earlier, and "The median year that homes were built was 1954, compared with 1979 for all of Rockingham County." Single detached houses made up 37.9% of the stock, attached and two- to four-unit buildings 27.0% and buildings of five or more units 30.2%, with multifamily housing "over half" (2014 housing report).
The city's draft 2024 Hazard Mitigation Plan update, posted in July 2024, names the Historic District among the areas at greatest risk from "coastal flooding, sea level rise, and groundwater intrusion," and lists North Mill Pond, South Mill Pond, the South End, Peirce Island, Little Harbour and Sagamore Creek among its named areas (draft 2024 plan). That's worth weighing before finishing a basement near the water, along with a radon test; the NH Radon Program offers free kits (NH DHHS radon).
FAQ
Portsmouth remodeling questions
Does finishing a basement or attic need a permit in Portsmouth?
Yes. The Inspection Department's FAQ says general renovation work needs a building permit, including "Creating new rooms or spaces within a structure" and structural changes or repairs. Interior renovations to a single-family home don't need zoning review.
When do repairs need a permit in Portsmouth?
Ordinary repairs such as painting, flooring, trim, insulating and repairing windows, doors or siding are exempt until their total cost exceeds $3,000. Work that alters a structural beam or required egress is never ordinary repair.
How large can an ADU be in Portsmouth?
Under the city's 2025 ADU Homeowner's Handbook, an attached ADU can have up to 750 square feet of gross living space, and a detached one 600 square feet with administrative approval or up to 750 with a Planning Board conditional use permit. The owner must live in one of the units, and converting interior space with no exterior change is usually allowed as of right.
Does adding a dormer trigger the demolition ordinance?
Outside the Historic District, partial roof removal for dormers or skylights is exempt from the citywide Demolition Ordinance. Inside the district, exterior changes go to the Historic District Commission, and a demolition with an HDC Certificate of Approval is exempt from separate demolition review.
What does it cost me to use New England Remodeling Pros?
Nothing. Asking is free for homeowners; the contractor prices the job, and the price and contract are between you and them.
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