What underlayment is best under laminate flooring in a New Brunswick home?

The best underlayment for laminate flooring in a New Brunswick home is a quality foam underlayment with an integrated vapour barrier — the vapour barrier component is essential in NB's Maritime climate where moisture from below the subfloor is a constant concern. The specific type depends on whether you are installing over plywood, concrete, or an existing floor.

Over plywood subfloors (the most common scenario in NB homes), use a standard foam underlayment with a built-in polyethylene vapour barrier. Products like basic poly-foam with a moisture barrier run $0.50-$0.75/sq ft and provide adequate cushion, sound dampening, and moisture protection. This is the minimum standard for any NB installation. Many NB homes, especially older properties with crawl spaces or pier foundations, have ground moisture that migrates upward through the subfloor assembly — the vapour barrier blocks this moisture from reaching the laminate's HDF core.

For a premium upgrade, consider cork underlayment at $1.00-$2.00/sq ft. Cork provides superior sound dampening (reduces hollow sound that laminate can produce over hard subfloors), adds thermal insulation that keeps floors warmer during NB's long heating season, and has natural moisture resistance. If you choose cork, add a separate 6-mil polyethylene vapour barrier beneath it for full moisture protection. Cork is particularly worthwhile in second-floor installations where sound transmission to rooms below matters.

Over concrete basement slabs, moisture protection becomes the top priority. NB basement concrete continuously releases moisture vapour, especially during spring snowmelt from April through June when the water table rises across the province. At minimum, use a foam underlayment with a heavy-duty vapour barrier (6-mil poly minimum). For basements with elevated moisture readings, install a dimpled drainage membrane ($1.50-$3.00/sq ft) directly on the concrete before any underlayment — this creates an air gap that allows moisture to dissipate without reaching the flooring system.

One critical mistake NB homeowners make: doubling up underlayment. If your laminate planks have a pre-attached foam pad on the underside (common with many mid-range and premium products), do not add a separate foam underlayment on top. The double cushion layer creates too much give, which damages click-lock connections over time and causes joints to separate — a problem compounded by NB's humidity-driven expansion and contraction cycles. With pre-attached pad laminate, install only a standalone vapour barrier sheet (6-mil poly, $0.15-$0.25/sq ft) if moisture protection is needed.

Additional tips for NB installations: overlap vapour barrier seams by 20cm (8 inches) and tape them with moisture-barrier tape — gaps in the vapour barrier defeat its purpose. Run the underlayment up the wall by 2-3cm behind the baseboard for added protection at the perimeter, where moisture intrusion is most likely. And never use carpet pad, old newspaper, or improvised materials as underlayment — they provide no moisture protection and void your laminate warranty.

For a typical NB installation, budget $0.50-$1.00/sq ft for standard foam-with-vapour-barrier underlayment, or $1.00-$2.00/sq ft for cork with a separate vapour barrier. On a 500 sq ft project, that is $250-$1,000 — a small cost that directly protects your $2,000-$4,000 laminate investment from NB's ever-present moisture challenges.

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Looking for experienced contractors? The New Brunswick Construction Network connects homeowners with qualified professionals:

• FRS Flooring Solutions
• RenoMe
• First united design & construction inc.
• Arctic Fox Construction Inc.
• 3Tone Construction Ltd