Sound insulation is the half of soundproofing that goes inside the cavity. It absorbs sound energy in the air space of a wall or floor; it does not block sound, because blocking is a job for mass and for breaking the rigid path between two sheets of drywall. That distinction, settled before the quote, is what separates a job that satisfies from one that disappoints. In the published laboratory walls, filling an empty stud cavity is worth roughly 4 to 11 points of Sound Transmission Class. Changing how the wall is built is worth two or three times that.
Burlington County asks for this work more than most South Jersey counties because of how it is built. 14.5% of its 185,617 units are single-family attached, 26,992 townhouses and duplex halves, with 3.9% more in three- and four-unit buildings and 2.9% in buildings of 50 units or more. That is a lot of shared walls and shared floors. The rest is detached houses, 64.4% of the county, where the complaint is internal: a bedroom over the garage, a laundry above the family room, an office beside the stairs.
Where soundproofing insulation pays in Burlington County houses
Townhouse party walls. Mount Laurel is 25.9% single-family attached, 5,178 units, the heaviest concentration in the county; Evesham is 18.8%, 3,784 units, then Burlington Township at 13.3%, Moorestown at 11.9% and Delran at 9.3%. A party wall is normally tight where you can see it and open above the ceiling line into a shared attic, so voices travel over the top of it rather than through it. Closing that gap at the roof line does more than anything added inside the wall below.
Small apartment buildings and duplexes. Delran carries 8.8% of its units in three- and four-unit buildings against 3.9% countywide, and 6.9% of Burlington Township sits in buildings of 50 units or more. In a duplex the stair chase, the shared plumbing wall and the floor over a unit are where the sound moves. Where a building is run as a whole, its walls, floors and roof belong to the owner or the association, and that decision sits with them rather than with the person hearing the noise.
Open-plan colonials from the 1980s and 90s. That era is 54.4% of Mount Laurel, 48.9% of Evesham, 36.8% of Burlington Township and 34.1% of Medford, and 31.0% of Burlington Township went up in the 1990s alone. Those houses have two-story entries, unlined joist bays over the living room and interior partitions framed with nothing in them. Batts in the bedroom and bathroom walls and the floor over the family room are cheap while a room is open and never cheap once it is closed.
Rooms built into the house later. A bedroom over the garage, a finished basement, a home office or a music room: those are the calls from the ranches and splits of Cinnaminson, Willingboro and Pemberton Township, where 43.5%, 61.4% and 47.6% of the housing dates from the 1960s and 70s and no floor plan allowed for a second living area.
Old plaster and open framing. Moorestown is 23.8% pre-1940, more than twice the county’s 10.7%. Lath and plaster carries useful mass, which is why those rooms often sound better than a modern partition, but balloon-framed stud bays run unbroken from the cellar to the attic floor and carry sound between stories like a speaking tube. Blocking and dense-pack in those bays is the fix, and the same work makes the house warmer.
How we do soundproofing insulation in Burlington County
We install the absorption half of the job: mineral wool and fiberglass batts, dense-pack cellulose, blown-in fiberglass and open cell foam. Resilient channel, a second layer of drywall, mass-loaded vinyl and a second row of studs are drywall and framing work, and on a wall that has to reach real privacy they matter more than the batt. In one manufacturer’s tested wood-stud walls, all with the same fiberglass batts, a 2×4 partition with one layer of 5/8-inch Type X each side rates STC 35; resilient channel on one side takes it to 48 and a second row of studs to 56. We say which of those numbers a budget is buying.
In an open wall or joist bay the batt is chosen on fit. Unfaced mineral wool and unfaced fiberglass both work; thickness matters more than density, and the batt has to fill the cavity with no gaps, cut around wiring and boxes rather than compressed behind them. Stone wool reads a few points higher in its own maker’s tested walls, though the two sets of results come from different laboratories. Where a bay is too crowded with pipes and cable for a batt to sit cleanly — a plumbing wall, a knee wall, an open-web truss floor — open cell foam fills it and absorbs well, with a measured noise reduction coefficient of 0.65 at 3 1/2 inches. Closed cell foam is the wrong product here: rigid and dense, it measures 0.10.
For a wall or ceiling already finished, dense-pack is the route that does not strip the room. Cellulose or fiberglass goes in through small holes at high density until the cavity is firm, flowing around wiring and pipes a batt would have been cut around, and the holes are patched. It adds no mass and breaks no rigid path, so a dense-packed single-stud wall is still a single-stud wall. Where the floor above has to be quieted, the covering on it moves impact noise further than anything in the joist bay, and that is a flooring decision.
Two details get checked on every quote. Any penetration beats any rating: a back-to-back electrical box, a duct crossing a partition, a can light, a gap at the top plate. And when a product sheet quotes an STC, ask for the laboratory, the report number and the test date, because an assembly rated in the 1960s can test several points lower today. Old insulation that is wet, settled or rodent-fouled comes out under containment before new material goes in; mold on framing or sheathing belongs to a remediation company first.
What soundproofing insulation costs in Burlington County
Most of our projects run between $3,500 and $12,500. A few interior partitions and a floor bay in a Mount Laurel townhouse, done while the drywall is off, sits at the bottom of that range. The number climbs with square footage of wall and ceiling, with dense-pack through plaster rather than batts into open framing, with bays blocked by plumbing and ductwork, and with how much old material comes out first. Drywall, channel and flooring are priced by the trades that install them, and we mark those lines clearly so comparing quotes is honest. The pieces are set out in our insulation cost guide.
Rebates for soundproofing insulation in Burlington County
Start with the names on the two bills. PSE&G supplies gas and electricity across Burlington Township, Cinnaminson, Delran, Moorestown, Mount Laurel and Willingboro; Pemberton Township takes electricity from JCP&L with PSE&G gas in one corner; Evesham and Medford divide both meters, electricity between PSE&G and Atlantic City Electric, gas between South Jersey Gas and PSE&G. Two different names means either utility’s program can take a project, and the gas programs require gas heat, so begin with the company billing your heating fuel.
Be clear-eyed about what the money is for. Whole Home Energy Solutions pays up to $7,500 on a project built around air sealing and the insulation an assessment models for energy savings. An interior partition between two bedrooms saves no energy, so quiet is not what the program buys; the exterior walls, attic and rim joists in the same house are another matter, and much of our sound work rides along with envelope work. Ask the assessment which measures count before the savings are modeled. PSE&G adds 0% on-bill repayment of up to $25,000 and starts with a BPI-certified contractor participating in its program, who sets the assessment fee; JCP&L and South Jersey Gas publish the formula, $2,000 at a modeled 5% energy saving plus $200 a point above it, capped at $7,500 and at half the project cost, with 0% financing of $2,500 to $25,000; Atlantic City Electric pays up to $7,500 on single-family residences through the program’s lender. Ask any installer, ourselves included, whether they participate.
Income-qualified households can have envelope work done at no cost through PSE&G Home Weatherization or the $14,000 programs at JCP&L, South Jersey Gas and Atlantic City Electric, and New Jersey Comfort Partners covers households at or below 250% of the federal poverty guidelines, $82,500 for a family of four in 2026, with oil, propane and kerosene homes referred to the state’s weatherization office. New Jersey’s IRA Home Energy Rebates are still in development and not open. The federal 25C tax credit ended for anything placed in service after 31 December 2025. Our New Jersey rebate guide has the rest.
Code and climate in Burlington County
Two codes touch this work. The building code sets the sound requirement between dwelling units in apartment and condominium buildings: walls, partitions and floor-ceiling assemblies have to reach STC 50 in a laboratory test, or a normalized noise isolation class of 45 when tested in the field, with floor-ceilings also reaching an impact insulation class of 50. It also requires penetrations for piping, ducts and electrical devices to be sealed, lined or otherwise treated so the rating survives. Townhouses and two-family houses fall under the residential code instead, where the requirement differs, so the building department settles what applies before the wall is closed.
The energy code comes in whenever a sound job touches an exterior wall or a ceiling. Burlington County is climate zone 4A, and under the 2024 IECC that New Jersey adopted on 17 August 2026 an exterior wall in new work takes R-30 in the cavity, or R-20 plus R-5 continuous, with R-49 at the ceiling. A partition inside the house has no R-value requirement at all, which is why the batt in it is chosen for fit and thickness rather than for a number. Existing homes fall under New Jersey’s Rehabilitation Subcode, where blown-in or batt insulation installed against the interior finish is ordinary maintenance with no permit, while foam plastic needs a permit, and we pull that one as part of the job.
Towns we serve in Burlington County
Sound work runs across all 40 municipalities in the county. These nine carry pages of their own.
Common questions about soundproofing insulation in Burlington County
Does wall insulation really work for noise?
It helps and it is not the whole answer. In the guideline tables a filled cavity is worth about 4 to 11 points of STC over an empty one, which takes a partition from speech you can follow to speech you can hear but not understand. Getting to real privacy takes mass and decoupling as well: another layer of board, resilient channel, or a second row of studs. We quote the batt plainly and tell you what the framing has to do for the rest.
What insulation is best for a Burlington County townhouse party wall?
An unfaced batt that fills the cavity without gaps, in either mineral wool or fiberglass; thickness beats density, and stone wool reads a few points higher in its own maker’s tested walls. But in the county’s attached housing, which runs to 25.9% of Mount Laurel and 18.8% of Evesham, the bigger win is usually above the ceiling, where the party wall often stops short of the roof and the two attics share air. Close that first, then fill the wall.
How do I quiet the floor and ceiling between two levels?
Fill the joist bays, seal what crosses them, and expect airborne noise to improve more than footsteps. A floor can rate well for voices and still pass every step through, because impact sound travels the framing. In an open-web truss floor, open cell foam fills bays that a batt cannot; below, resilient channel and a second layer of board are drywall work. Carpet, pad or a proper underlayment on the floor above moves the impact number further than anything in the cavity.
Can you soundproof an apartment in Burlington County?
We work inside the unit an owner controls, and we say plainly where the work stops. In the larger buildings, which hold 6.9% of Burlington Township’s units and 5.1% of Evesham’s, the party walls, floor assemblies and roof are the owner’s or the association’s, so that scope is their call. In an owner-occupied duplex, and Delran has more of those than most of the county at 8.8% in three- and four-unit buildings, the stair chase and the shared plumbing wall are usually the first fix.
Free energy audit in Burlington County
On a noise visit we walk both sides of the problem: what is in the wall or floor now, where the assembly is open and where it is closed, what crosses it — ducts, cans, back-to-back boxes, a plumbing stack — and whether the party wall closes at the roof line. Then we say which part of the result comes from insulation and which part needs drywall or framing, so the money goes where the decibels are.
The visit and the written scope cost nothing and commit you to nothing. Call 914-554-2289, 8am–8pm, seven days. The Home Insulators is family-owned, has worked out of New Rochelle, NY since 2015, and staffs every job with its own 100-plus-person in-house crew; we never subcontract.
Get my free estimateor call 914-554-2289, 8am–8pm every day