How do I handle flooring at a doorway threshold between rooms in NB?

Doorway thresholds require a transition strip or a continuous-flow approach depending on whether the flooring material changes between rooms, and getting this detail right is especially important in NB homes where seasonal humidity swings cause significant expansion and contraction. A poorly handled threshold is one of the most visible signs of amateur installation.

If the same flooring continues through the doorway into the next room, the cleanest approach is to run the flooring continuously without a transition strip. This creates a seamless look that makes both rooms feel larger. However, there is an important caveat for floating floors in NB — manufacturer guidelines typically limit continuous floating floor runs to 30-40 feet in any direction before requiring an expansion break. In NB's Maritime climate, where indoor humidity can swing from 20% in January to 65% in August, respecting these limits is critical. If the combined room length exceeds the manufacturer's maximum, you need a T-moulding transition even with the same product.

When flooring materials change between rooms — for example, hardwood in the living room meeting LVP in the kitchen — a transition strip is required. The most common types are T-mouldings (for floors at the same height), reducers (when one floor is higher than the other), and thresholds or end caps (where flooring meets a different surface like tile or carpet). Quality transition strips in NB run $15-$50 each installed, depending on material and style.

For the door frame itself, the flooring should slide underneath the door casing rather than being cut to fit around it. Use an oscillating multi-tool or a hand saw laid flat on a scrap piece of your flooring to undercut the casing and door jamb at the correct height. This creates a tight, professional look with no visible gap. In older NB homes — and there are many pre-1960s homes in Fredericton, Saint John, and Moncton — you may find hardwood casings that are quite thick, so take your time with the undercut.

The expansion gap at doorways is where many DIY installations go wrong. When floating flooring passes through a doorway continuously, the doorway itself is a pinch point. If the flooring fits too tightly against the door frames on both sides, summer expansion has nowhere to go and the floor buckles. Leave the standard 8-12mm gap under the casings where it will be hidden.

For tile-to-other-flooring transitions, a metal or stone threshold strip anchored to the subfloor provides a durable, clean transition. This is common in NB bathrooms where tile meets hallway hardwood or LVP. The threshold also acts as a moisture break, preventing water from migrating from the bathroom into the hallway flooring.

Height differences between rooms are common in NB homes, especially where additions have been built over the decades. A reducer transition strip handles differences up to about 10-15mm cleanly. For larger height differences, the subfloor in the lower room may need to be built up with plywood before the new flooring goes down.

If you are hiring a professional installer, discuss all transitions during the quoting stage — the number of doorways and transition types can significantly affect both the cost and timeline of your project.

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

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