Do I need underlayment for every type of flooring in my NB home?

No, not every flooring type requires a separate underlayment — but in New Brunswick's Maritime climate, some form of moisture protection is needed for almost every installation, especially over concrete. The answer depends on your flooring type, subfloor material, and whether you are installing above or below grade.

Here is a breakdown by flooring type for NB conditions.

Laminate flooring always requires underlayment. Laminate's HDF core is vulnerable to moisture from below, and the floating installation method needs a cushioning layer to reduce noise and accommodate minor subfloor irregularities. Use a foam underlayment with an integrated vapour barrier ($0.50-$1.00/sq ft) over any subfloor in NB. Over concrete basement slabs, this vapour barrier is absolutely critical — Maritime ground moisture migrates continuously through concrete. One important rule: if your laminate comes with pre-attached padding on the underside, do not add a separate underlayment on top of that. Doubling up cushion layers creates excessive give that damages click-lock connections over time.

Luxury vinyl plank (LVP) follows similar rules to laminate, with one key difference — many LVP products come with pre-attached underlayment, and manufacturers of those products specifically state that no additional underlayment should be used. Check your product's installation guide first. If your LVP does not have pre-attached padding, use a thin foam underlayment (1-1.5mm) with a vapour barrier. Over NB basement concrete, the vapour barrier is non-negotiable regardless of what is pre-attached.

Nail-down solid hardwood does not use a traditional cushioned underlayment — the flooring is fastened directly to the plywood subfloor, and any cushion layer would compromise the nail hold. However, NB installers commonly lay 15-lb asphalt felt (tar paper) or a specialized hardwood vapour retarder between the subfloor and hardwood. This reduces squeaks, provides a mild moisture buffer, and allows the hardwood to move freely with seasonal expansion. Cost is minimal — roughly $0.20-$0.40/sq ft.

Engineered hardwood depends on the installation method. Floating engineered hardwood needs underlayment similar to laminate. Glue-down engineered hardwood goes directly onto the subfloor with no underlayment — the adhesive bonds to a clean, flat surface. Nail-down engineered hardwood uses felt paper, same as solid hardwood.

Tile flooring does not use underlayment in the traditional sense. Tile requires a rigid substrate — cement backer board over plywood, or properly prepared concrete. A cushioned underlayment under tile would cause cracked tiles and failed grout. In wet areas (bathrooms, laundry rooms), a waterproofing membrane applied over the backer board serves as the moisture protection layer.

Carpet uses a separate pad (underpad or cushion) rather than what the flooring industry calls underlayment. Quality carpet pad ($0.50-$1.50/sq ft) provides cushion, insulation, and extends carpet life. In NB basements, use a moisture-resistant synthetic pad — never a fibre-based pad that will absorb Maritime moisture from the concrete and develop mould.

Cork underlayment ($1.00-$2.00/sq ft) deserves special mention for NB homes. Its thermal insulation properties make a noticeable difference during our long heating season — floors feel warmer underfoot, and it reduces heat loss through the floor assembly. It also provides excellent sound dampening and has natural antimicrobial properties that resist mould in humid Maritime conditions.

When in doubt, check your specific flooring product's installation instructions — manufacturers specify exactly what underlayment is required, recommended, or prohibited. Following these specifications also protects your warranty, which matters when you are investing $4,000-$15,000 in new flooring.

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

• Forever Epoxy Inc
• Gionetterenovations
• First united design & construction inc.
• Modern Epoxy Inc
• Thirty Four Renovations