Why Flooring Gaps Happen—and How Custom Transitions and Stair Nosings Prevent Them

Why Your Flooring Moves — and What You Can Do About It

One of the most overlooked details in flooring installations is how the material expands and contracts over time. Whether it’s solid hardwood, engineered planks, laminate, or luxury vinyl, every flooring type responds to changes in temperature and humidity. Gaps, buckling, and noisy joints aren’t just annoying — they’re often signs that movement wasn’t properly accounted for during installation.

At FC Millworks, we specialize in the finishing details that help flooring perform at its best, long after the crews have packed up. From transition moldings to a luxury vinyl flooring stair nosing and custom reducers, we see firsthand how proper spacing and precision make the difference between a good install and one that needs repairs within the year.

Why Flooring Expands and Contracts

Flooring materials are affected by the relative humidity in your home. In dry conditions, planks shrink. In humid conditions, they swell. This natural movement varies by material:

• Solid hardwood expands and contracts the most.

• Engineered hardwood is more stable due to its layered core.

• Luxury vinyl plank (LVP) is highly water-resistant but can still expand slightly with temperature swings.

• Laminate has a fiberboard core that swells when exposed to moisture and shrinks when dry.

Even small fluctuations — a few millimetres per board — can cause noticeable issues when multiplied across a room. This is why flooring details matter. Leaving the right gaps, using the right underlayment, and installing flexible transitions are all part of managing this movement properly.

Why Gapping and Buckling Happen

When boards don’t have enough space to expand, they push against each other and the walls. This creates pressure that leads to buckling, especially in summer or during sudden humidity spikes. On the flip side, dry winters cause boards to contract, which can result in unsightly gaps if planks weren’t placed snugly or the wrong adhesive was used.

Some installers assume that floating floors like laminate or LVP don’t need careful expansion planning — but that’s a mistake. At FC Millworks, we’ve been called in to repair floors that lifted at doorways or bunched up around stair transitions simply because expansion gaps were skipped or transitions were installed too tightly.

Managing Movement in Open Spaces

Large, open-plan homes present a bigger challenge for expansion. The longer the run of flooring, the more cumulative movement you’ll get. To manage this, we often install transition strips at doorways or between rooms, especially when switching directions or crossing thresholds. These transitions can be subtle and attractive when made from the same material as the floor.

When FC Millworks fabricates reducers and transitions, we cut them directly from the same flooring planks. This ensures consistent grain direction, color match, and a clean visual finish. Unlike store-bought pieces, our custom transitions blend into the floor instead of standing out.

Why Stair Finishing Requires Special Attention

Stairs are especially sensitive to flooring movement because they’re fixed on multiple planes — horizontal treads and vertical risers. When the flooring moves but the nosings stay rigid, you end up with separation, lifting, or cracked caulking.

This is why we build luxury vinyl flooring stair nosing using the same planks as the floor. Each nosing is designed with precision to accommodate slight movement while remaining secure and flush with the tread. We also recommend using flexible adhesives and allowing proper curing time to minimize stress during seasonal changes.

Acclimating Flooring Before Installation

One of the simplest ways to reduce post-installation issues is to acclimate the flooring properly. This means letting the planks sit in the space where they’ll be installed — typically for 48 to 72 hours — so they can adjust to the local humidity. Skipping this step is a common shortcut that often leads to callbacks.

Even vinyl and laminate products benefit from this practice. Though they’re more stable than hardwood, they still need time to reach equilibrium with the room environment. Acclimation is especially important in new builds where humidity levels can still be adjusting due to drywall or concrete curing.

Using the Right Underlayments and Materials

The materials under your floor are just as important as what’s on top. The right underlayment allows for slight expansion and contraction, helps absorb sound, and provides a moisture barrier where needed. In the case of floating floors, it also gives the planks room to move while staying flat.

At FC Millworks, we’ve seen too many floors fail prematurely because someone tried to cut corners with cheap underlayments or skipped the vapor barrier in a basement. We help homeowners and builders choose materials that will keep their flooring quiet, stable, and long-lasting.

Tips for Maintaining a Stable Environment

While installation is key, long-term performance also depends on maintaining consistent indoor conditions. The ideal indoor humidity for most flooring is between 35% and 55%. Here are some quick tips to help reduce seasonal stress on your floors:

• Use a humidifier during dry winter months

• Run a dehumidifier in humid summer months

• Avoid sudden temperature changes indoors

• Keep heat vents from blowing directly onto flooring edges

• Use felt pads under furniture to prevent stress on planks

Controlling your indoor environment keeps your flooring stable, and also extends the life of custom features like stair nosings and trim moldings.

Final Thoughts: Expansion Gaps Are Not Optional

No matter how advanced flooring materials become, they still move. Ignoring that reality is asking for problems. Expansion gaps, flexible transitions, and proper stair installation are essential parts of a floor that looks and feels great for years — not just the day it’s installed.

At FC Millworks, we don’t just fabricate beautiful custom stair parts, nosings, and moldings — we build them with the realities of flooring movement in mind. That’s why we work closely with flooring installers, contractors, and homeowners to make sure every finish detail works with the floor, not against it.

If you’re investing in new flooring or planning a renovation, don’t underestimate how much flooring details matter. From precision-milled stair nosings to movement-friendly transitions, the little things we build make a big difference in how your home performs every day.