Basement finishing in South Jersey
Cost vs. Value's 2025 Philadelphia market, the closest to Camden County, puts a basement remodel at $52,1991, close to the $52,0122 national figure. The local factor is radon: NJDEP places 43 Camden County municipalities in its high-potential tier, including Runnemede and Somerdale, so test before anything is framed.
Calls are recorded. One independent company that handles basement finishing in the South Jersey area answers.
Updated October 12, 2026
What the lower level costs and returns
Cost vs. Value's standard basement job includes a wet bar and a small full bath. Philadelphia prices it almost exactly at the national average but expects less of it back at resale.
| Measure | Philadelphia market | U.S. average |
|---|---|---|
| Basement remodel, job cost | $52,1991 | $52,0122 |
| Basement remodel, resale value | $33,9371 | $36,9052 |
| Basement remodel, cost recouped at resale | 65%1 | 71%2 |
Waterproofing, a radon system and an escape window aren't in that figure. Get them priced as separate lines, so you can see what a dry, safe shell costs before choosing finishes.
Radon tiers across the county
NJDEP rates each municipality by the share of tested homes at or above the action level. A handful of Camden County towns land in the high tier, about as many as in Burlington County, and most of the rest are moderate.
| Measure | Camden County | Burlington County |
|---|---|---|
| Camden County municipalities rated Tier 1 (high radon potential) | 43 | 33 |
| Camden County municipalities rated Tier 2 (moderate radon potential) | 233 | 273 |
| Camden County municipalities rated Tier 3 (low radon potential) | 73 | 63 |
NJDEP recommends that all homes be tested for radon, because levels vary widely even within a tier and homes in low or moderate radon areas can still test high.4 The tier describes the town, not your house.
Town by town
The same table lists each town's share of tested homes at or above the action level. Lawnside, Runnemede, Magnolia and Somerdale are the high-tier towns; Cherry Hill and Haddonfield sit in the middle tier and Collingswood in the low one.
| Measure | Share of tested homes at or above the action level |
|---|---|
| Radon tests at or above 4 pCi/L, share of homes tested | 42%3 |
| Radon tests at or above 4 pCi/L, share of homes tested | 31%3 |
| Radon tests at or above 4 pCi/L, share of homes tested | 30%3 |
| Radon tests at or above 4 pCi/L, share of homes tested | 26%3 |
| Radon tests at or above 4 pCi/L, share of homes tested | 19%3 |
| Radon tests at or above 4 pCi/L, share of homes tested | 14%3 |
| Radon tests at or above 4 pCi/L, share of homes tested | 4%3 |
In the high-tier boroughs, plan the vent pipe route and fan spot along with the framing. Elsewhere, a short test before the drywall still costs far less than retrofitting a system through finished walls.
Rain and frost at Philadelphia International
The airport across the river is the nearest major station with published normals for Camden County. It logs a long freezing season and a steady count of days with an inch or more of rain.
| Measure | Philadelphia International Airport |
|---|---|
| Days a year with a low at or below freezing | 77 days5 |
| Days a year with at least an inch of precipitation | 11 days5 |
The EPA advises cleaning and repairing gutters regularly and making sure the ground slopes away from the foundation so water does not enter or collect around it.6 Short downspouts and patios pitched toward the house are the usual culprits, and both cost less to fix than an interior drain.
Foundations from two eras
Camden County's postwar houses mostly sit on concrete block, while prewar houses in the older river towns may have brick or stone below grade. Census year-built counts show how much of each the county has.
Houses that may have a basement
The Census Bureau doesn't count basements. Detached houses are the closest measure, and they make up a smaller share of homes in Camden County than in Burlington County.
| Measure | Camden County | Burlington County |
|---|---|---|
| Homes that are single-family detached | 55%8 | 64%8 |
| Homes that are single-family attached (twins, rowhouses, townhouses) | 17%8 | 15%8 |
Twins and rowhouses often share a foundation wall with the neighbor, so moisture control and fire separation in the basement involve the other side of the wall too.
Permits
Finishing a basement is permit work under New Jersey's statewide code, filed with your town's construction office. The Rehabilitation Subcode treats the job as an alteration, so a lower existing ceiling can usually stay, but any new bedroom needs an escape opening and hard-wired smoke alarms, and the alteration brings smoke and carbon monoxide alarms for the house. Replacing a basement window in its existing opening is maintenance; enlarging it is not.
- New Jersey's construction code is the same statewide, with no separate local requirements; municipally employed, state-licensed construction officials and inspectors enforce it, and the owner or the owner's agent, such as the contractor, is responsible for getting the permits.9
- Under New Jersey's Uniform Construction Code it is unlawful to renovate, alter, repair or enlarge a building without first applying to the construction official, or to the subcode official when only one trade is involved, and getting a permit.10
- New Jersey's Division of Codes and Standards says finishing an existing basement is an alteration under the Rehabilitation Subcode, and nothing requires raising the existing ceiling to 7 feet just because the space is being finished.11
- When an alteration creates a bedroom below the fourth floor, it needs a window or exterior door that meets the subcode's escape-opening requirements, plus a hard-wired smoke alarm in the bedroom and a second one near it.12
- The Rehabilitation Subcode requires smoke alarms in any one- or two-family house that undergoes an alteration, and carbon monoxide detection in buildings that have a fuel-burning appliance or an attached garage.12
- Replacing a window or door in the same opening, without changing the opening's size or framing, counts as ordinary maintenance in New Jersey, and that includes emergency escape windows.10
- New Jersey's code allows plumbing, electrical and HVAC work only by people licensed to do it, except a single-family homeowner working on his or her own home, and the licensed contractor's seal and signature go on the matching permit application.10
Checked October 12, 2026
Before you hire
In New Jersey, ask for the company's home improvement contractor business registration number and confirm it's active with the Division of Consumer Affairs, because registering takes proof of at least $500,00023 per occurrence in liability insurance.
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Test before you frame
The EPA recommends testing for radon on the lowest lived-in level, so a basement that hasn't been tested should be tested before it is remodeled; fixing a radon problem is usually easier and cheaper before the basement is finished.13 NJDEP rates a town Tier 1 when at least 25 percent of tested homes measure 4 picocuries per liter or more, Tier 2 at 5 to 24 percent and Tier 3 below 5 percent, each based on at least 25 homes tested.3 NJDEP rates four Camden County municipalities, Lawnside, Magnolia, Runnemede and Somerdale, as Tier 1 for high radon potential; Cherry Hill and Haddonfield are Tier 2 and Collingswood is Tier 3.3 The EPA's guidance is to fix your home if radon tests at 4 picocuries per liter or higher, and to consider fixing it between 2 and 4.14
Department of Community Affairs rules require builders to include radon-resistant features in new homes built in Tier 1 areas.15 An older rancher in one of those boroughs most likely went up without that pipe, so finishing the basement is a good moment to ask about roughing one in. By New Jersey law, every business and professional that tests for radon or installs radon mitigation must be certified by NJDEP.4
Under New Jersey law, a seller whose home has been tested for radon must give the buyer, when the contract of sale is signed, a copy of the test results and evidence of any mitigation.15 Keeping the test result and any mitigation record with the house papers answers a buyer's question before it's asked.
Headroom and escape windows
New Jersey's Division of Codes and Standards says finishing an existing basement is an alteration under the Rehabilitation Subcode, and nothing requires raising the existing ceiling to 7 feet just because the space is being finished.11 New houses face the stricter model-code number. The 2021 IRC requires habitable space and hallways, including the parts of a basement that contain them, to have a ceiling at least 7 feet high, and bathrooms and laundry rooms at least 6 feet 8 inches.16 In a postwar Camden County basement, the main beam and the ducts usually decide where the finished ceiling ends up.
When an alteration creates a bedroom below the fourth floor, it needs a window or exterior door that meets the subcode's escape-opening requirements, plus a hard-wired smoke alarm in the bedroom and a second one near it.12 Under that code, an escape opening needs a net clear opening of at least 5.7 square feet, at least 24 inches high and 20 inches wide, with its bottom no more than 44 inches above the floor.16 The small hopper windows set high in a block wall won't qualify, so a bedroom means cutting a larger opening and digging a well outside. An escape window whose bottom sits below the ground outside needs an area well of at least 9 square feet, at least 36 inches out from the wall and 36 inches wide, big enough for the window to open fully.16
Keeping it dry
Before turning basement space into living space, the EPA advises checking it for leaks and other signs of moisture and fixing any moisture problem first, because damp basements promote mold and other biological growth.13 The EPA warns that carpet on a basement slab can stay damp from water or vapor coming up through the concrete, or from room moisture condensing on a slab that is colder than the air, and either can lead to mold.13
Building America advises keeping fiberglass batts and cellulose out of contact with foundation walls, and not putting polyethylene sheeting, vinyl or foil wallpaper, or epoxy, oil or alkyd paint on the inside of basement walls, because they trap moisture.17 ENERGY STAR's guidance for existing homes, based on the 2021 IECC, is R5 insulating sheathing or R13 batts on basement walls in climate zone 3, R10 sheathing or R13 batts in zones 4A and 4B, and R15 sheathing or R19 batts in zones 4C and 5 through 8.18 Ask which climate zone and wall build-up the bid assumes, and check that the permit drawings say the same.
In Cherry Hill, anyone planning development in a flood hazard area must first apply to the floodplain administrator and obtain the required permit, which can be needed in addition to a building permit.19 If your lot is near the Cooper River or a creek, find out whether it is mapped before you finish anything below grade.
Paying for it
Camden County's Home Improvement Program loans must be used to correct housing code violations that are dangerous or injurious to the occupants; ordinary repairs, home maintenance, cosmetic work and general property improvements aren't eligible.20 A finished family room isn't what Camden County's loan is for, but an unsafe heater or wiring hazard in the same basement might qualify. Camden County's Home Improvement Program, run through the Camden County Improvement Authority, gives owner-occupants of single-family homes who meet income limits a deferred payment loan with no interest and no monthly payments, repaid when title to the home is transferred; applicants must have lived in the home at least 12 months.20
The basement stair
More than one in four adults 65 and older fall each year.21 Postwar cellar stairs are often steep, open on one side and lit by a single pull chain. Finishing the space is the time for a second handrail, light switches at the top and the bottom, and tread edges that contrast with the steps. NAHB's Certified Aging-in-Place Specialist (CAPS) credential trains remodelers in home modifications for aging in place.22
What happens when you call
When you call the number on this page, a recorded line connects you with one independent company that handles basement finishing in the South Jersey area. What gets built, when and at what price is up to you and that company.
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After you're connected
Look up the company's state registration before you pay anything. New Jersey's Contractors' Business Registration Act requires every home improvement contractor business, from a sole proprietorship up, to register with the Division of Consumer Affairs every year before selling or making home improvements, unless the law exempts it.23 The Division of Consumer Affairs' License Verification System is a real-time lookup; its Business Search finds home improvement contractor businesses by business name, license number or city and lists each one's registration number, license type, status and city.24 Check a New Jersey license
Ask who will pull the building, plumbing and electrical permits, and make sure the radon work is done by a state-certified firm. A New Jersey home improvement contract for more than $500, and any change to its terms, must be in writing and signed by all parties, and must list the contractor business's legal name, business address and registration number, include a copy of its liability insurance certificate with the insurer's phone number, and state the total price including any finance charges.25
Questions people ask
What does finishing a basement cost in South Jersey?
Cost vs. Value's 2025 Philadelphia figure for its standard job is $52,1991, and area agents put the resale value at $33,9371. Waterproofing, radon work and a new escape window come on top.
Is radon a real concern in Camden County?
In some towns more than others. NJDEP rates four Camden County municipalities, Lawnside, Magnolia, Runnemede and Somerdale, as Tier 1 for high radon potential; Cherry Hill and Haddonfield are Tier 2 and Collingswood is Tier 3.3 NJDEP recommends that all homes be tested for radon, because levels vary widely even within a tier and homes in low or moderate radon areas can still test high.4
Does New Jersey make me raise a low basement ceiling?
Usually not in an existing house. New Jersey's Division of Codes and Standards says finishing an existing basement is an alteration under the Rehabilitation Subcode, and nothing requires raising the existing ceiling to 7 feet just because the space is being finished.11 Your construction office reviews the plans.
Can the basement become a rental apartment?
That's a separate project with its own rules. In one- and two-family houses, work that creates an additional dwelling unit must separate the new unit from the existing one with fire partitions or horizontal assemblies.12 Check your town's zoning before anything is drawn.
Sources
Page updated October 12, 2026. How we source our numbers
- Zonda / Journal of Light Construction, Cost vs. Value 2025, Philadelphia, Pennsylvania. Released 2025. Philadelphia, PA (Cost vs. Value market). Industry source.
- Zonda / Journal of Light Construction, Cost vs. Value 2025, national. Released 2025. United States. Industry source.
- New Jersey Department of Environmental Protection, Radiation Protection Element, Radon Tier Assignment Report (municipal radon potential). No publication date. Camden County, New Jersey.
- New Jersey Department of Environmental Protection, Radiation Protection Element, Radon. No publication date. View source.
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020. Released 2021. Days a year with a low at or below freezing, Philadelphia International Airport (station USW00013739), Days a year with at least an inch of precipitation, Philadelphia International Airport (station USW00013739).
- U.S. Environmental Protection Agency, A Brief Guide to Mold, Moisture and Your Home. Released February 18, 2026. View source.
- U.S. Census Bureau, American Community Survey 2020–2024 5-year, table B25034. Released January 29, 2026. Camden County, New Jersey, Burlington County, New Jersey.
- U.S. Census Bureau, American Community Survey 2020–2024 5-year, table B25024. Released January 29, 2026. Camden County, New Jersey, Burlington County, New Jersey.
- New Jersey Department of Community Affairs, Division of Codes and Standards, The New Jersey State Uniform Construction Code: General Information. Released May 2006. View source.
- New Jersey Department of Community Affairs, Division of Codes and Standards, N.J.A.C. 5:23-2, Uniform Construction Code: Administration and Enforcement. Released August 17, 2026. View source.
- New Jersey Department of Community Affairs, Division of Codes and Standards, Construction Code Communicator, Winter 2025 ('Ceiling Heights in Existing Homes'). Released 2025. View source.
- New Jersey Department of Community Affairs, Division of Codes and Standards, N.J.A.C. 5:23-6, Rehabilitation Subcode. Released August 17, 2026. View source.
- U.S. Environmental Protection Agency, Remodeling Your Home and Indoor Air Quality. Released February 17, 2026. View source.
- U.S. Environmental Protection Agency, Health Risk of Radon. Released June 24, 2026. View source.
- New Jersey Department of Environmental Protection, Radiation Protection Element, Radon & Real Estate. No publication date. View source.
- International Code Council, 2021 International Residential Code, Chapter 3 Building Planning. Released 2021. View source. Industry source.
- U.S. Department of Energy, Building America Top Innovations: Basement Insulation Systems. No publication date. View source.
- ENERGY STAR (U.S. EPA and U.S. DOE), Recommended Home Insulation R-Values. No publication date. View source.
- Township of Cherry Hill, Code of the Township of Cherry Hill, Chapter 12, Flood Damage Prevention. Released July 10, 2023. View source.
- Camden County Board of Commissioners / Camden County Improvement Authority (brochure posted by the Borough of Haddon Heights), Camden County Home Improvement Program (HIP) brochure. No publication date. View source.
- Centers for Disease Control and Prevention, Facts About Older Adult Falls. Released September 4, 2026. View source.
- National Association of Home Builders, Certified Aging-in-Place Specialist (CAPS). No publication date. View source. Industry source.
- New Jersey Division of Consumer Affairs, Home Improvement Contractor Business: Frequently Asked Questions. Released March 3, 2025. View source.
- New Jersey Division of Consumer Affairs, License Verification System. No publication date. View source.
- New Jersey Legislature, P.L.2023, c.237 (Home Improvement and Home Elevation Contractor Licensing Act; amendments to the Contractors' Business Registration Act). Released January 8, 2024. View source.