How important is expansion gap sizing for flooring in NB's Maritime climate?

Expansion gaps are critically important for any floating floor installation in New Brunswick — arguably more so here than anywhere else in Canada outside coastal BC. The province's Maritime climate produces annual indoor humidity swings of 30–50% between the bone-dry heating season and the humid summers, and every floating floor material responds to these swings by expanding and contracting. Without properly sized expansion gaps, that movement has nowhere to go, and the result is buckling, peak-tenting, or permanent damage to your floor.

Most manufacturers specify 8–12mm (roughly 5/16 to 1/2 inch) expansion gaps around all walls, door frames, pipes, cabinets, islands, and any other fixed object. In New Brunswick, you should always target the upper end of that range — 10–12mm minimum. Here is why: during NB's winter heating season (October through April), forced-air heating can drop indoor humidity to 20–30%, causing floating floors to contract. Come June through September, Maritime humidity pushes indoor levels above 60–65% without air conditioning, and those same planks expand significantly. A gap that looks generous in January may be completely compressed by July. If the floor runs out of room to expand, it pushes against walls and door frames, and the only place it can go is up — creating visible buckles and peaks in the middle of your floor.

Expansion gaps are needed around every fixed object, not just walls. This is a common mistake in NB open-concept homes where a kitchen island or built-in cabinet sits in the middle of a large floor area. The flooring must have a gap around the base of every island, support post, and plumbing penetration. For pipes, drill the hole at least 20mm larger than the pipe diameter and cover with an escutcheon plate. For kitchen islands, use quarter-round or shoe moulding to conceal the gap while still allowing movement.

For laminate flooring, the HDF core absorbs and releases moisture more aggressively than vinyl, making expansion gaps even more critical. NB installers often recommend going to 12–15mm for laminate in homes without consistent humidity control. For luxury vinyl plank (LVP), SPC-core products are more dimensionally stable than laminate, but they still expand and contract with temperature changes — LVP is actually more responsive to temperature than humidity, so gaps matter in rooms with direct sunlight or near heat sources. Engineered hardwood floated as a click-lock floor also requires full expansion gaps, and the wood component makes it responsive to both humidity and temperature.

Maximum run lengths are another gap-related consideration that NB's climate makes more important. Most manufacturers specify a maximum continuous run of 30–40 feet in any direction before requiring an expansion break (a T-moulding transition). In NB's high-swing humidity environment, respect these limits strictly — pushing beyond them in a large open-concept space is one of the most common causes of mid-floor buckling.

Practical tips for NB installations: use spacers during installation to maintain consistent gaps along walls. Never pin the flooring against a fixed object. When reinstalling baseboards, leave them resting on top of the flooring surface but nail them into the wall only — never nail through the baseboard into the flooring, as this pins the floor and prevents movement. And if you are installing during NB's dry winter months, remember that the floor is at its most contracted state — it will only get wider come summer, so your gaps will shrink. Installing during the shoulder seasons (spring or fall) when humidity is moderate gives you the most balanced starting point.

---

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

• The Garbage Guys Ltd
• Forever Epoxy Inc
• First united design & construction inc.
• Thirty Four Renovations
• FRS Flooring Solutions