How much does it cost to add underlayment with soundproofing properties when installing flooring in a NB multi-storey home?

Soundproofing underlayment in a New Brunswick multi-storey home typically adds $1.00–$3.50/sq ft to your flooring project, depending on the product and performance level you choose. For a typical 300–500 sq ft upper-floor room, that's $300–$1,750 in underlayment costs alone — a meaningful but worthwhile investment when you're trying to reduce impact noise between floors.

Understanding What Soundproofing Underlayment Actually Does

There are two types of sound transmission to understand before choosing a product. Impact noise (IIC rating) is the thud of footsteps, dropped objects, and chair scraping — the type that travels through the floor structure itself. Airborne noise (STC rating) is voices, music, and TV sound travelling through the air and walls. Underlayment primarily addresses impact noise. For NB multi-storey homes — especially older two-storey houses common in Fredericton, Saint John, and Moncton — impact noise between floors is usually the bigger complaint, and the right underlayment makes a real difference.

Look for products with an IIC rating of 65 or higher for meaningful impact noise reduction. Standard foam underlayment ($0.50–$1.00/sq ft) provides minimal sound control. You want to step up to one of the purpose-built options.

Cork underlayment ($1.00–$2.00/sq ft) is the most popular mid-range choice in NB. It's a natural material, provides excellent thermal insulation (a genuine bonus during NB's long heating season), and delivers solid IIC performance in the 60–70 range. It also handles NB's humidity cycles well without degrading.

Rubber or composite acoustic underlayment ($1.50–$3.50/sq ft) — products like QuietWalk Plus, Acoustiblok, or Roberts AirGuard — deliver the highest IIC ratings (70+) and are the best choice when sound control is the primary goal. These denser products are especially worth the investment under laminate or LVP, which transmit impact noise more readily than carpet.

NB-Specific Considerations

If you're in a condo or multi-unit building anywhere in NB, check your condo bylaws before purchasing anything. Many NB condo corporations specify minimum IIC and STC ratings — commonly IIC 50–65 — that must be met when replacing flooring. Installing a beautiful new LVP floor with inadequate underlayment can result in a bylaw complaint from your downstairs neighbour and a costly redo.

NB's humidity swings also matter here. Some acoustic underlayments include a built-in vapour barrier, which is valuable on upper floors with any moisture concern below. If your underlayment doesn't include one, add a 6-mil poly vapour barrier layer, particularly over concrete subfloors or in homes with crawl spaces — both common in NB housing stock.

One critical rule: never double up underlayment layers or install acoustic underlayment under flooring that already has pre-attached padding. The combined thickness creates excessive flex in the click-lock joints of laminate and LVP, causing premature joint failure. Choose one product that does both jobs.

Practical Tips

For a typical upper-floor bedroom or living room installation, budget $1.50–$2.50/sq ft for quality acoustic underlayment as your sweet spot — cork or a mid-range composite product. Pair it with a quality LVP or engineered hardwood and you'll have a noticeably quieter floor. If you're installing carpet, the acoustic pad is built into the carpet system — choose a 8 lb density rubber pad ($0.75–$1.50/sq ft) for the best sound performance.

For the highest-performance installations — home offices, media rooms, or condo situations with strict bylaws — hire a flooring professional who can specify products with documented IIC/STC ratings and provide documentation for your condo corporation if needed. New Brunswick Flooring can match you with a local installer familiar with NB condo requirements — get matched for free through the New Brunswick Construction Network directory.