A wooden or parquet floor doesn't stay perfectly still once it's fitted. Wood is a natural material and it keeps responding to the air around it long after installation, swelling slightly as humidity rises and shrinking back as the air dries out. This is normal in parquet flooring, and it's built into how a floor is designed and fitted from the outset. This guide covers why it happens, what humidity range keeps the movement manageable, and how to tell normal seasonal movement apart from an actual problem.
What causes wood floors to expand and contract?
Wood is hygroscopic, meaning it absorbs and releases moisture depending on the humidity in the air around it. When humidity rises, the boards take on a small amount of moisture and expand slightly. When the air dries out, they release that moisture and contract. Humidity is the main driver of this movement, not temperature on its own, though the two are closely linked indoors because heating systems dry the air out at the same time they warm a room.
In UK homes, this typically follows the seasons. Summer brings higher outdoor humidity and windows staying open longer, which pushes indoor moisture levels up and causes boards to expand slightly. Winter heating dries the air out, which is when boards contract and small gaps can appear between them. This cycle repeats every year and is a normal part of owning a wood floor, not a fault.
Is it normal for gaps to appear between boards?
Yes, small seasonal gaps that open in winter and close again in summer are completely normal and don't need any repair. This is different from gaps that keep growing over several years, don't close back up when humidity rises, or appear alongside other issues like loose blocks or cupping, which point to a more serious moisture imbalance rather than ordinary seasonal movement. If you're unsure which you're looking at, our guide to the main parquet flooring issues goes through the warning signs in more detail.
What humidity range should you aim for?
Most flooring manufacturers recommend keeping indoor relative humidity somewhere between roughly 40% and 60%, with a fairly stable temperature around 18 to 22°C. Staying within that range, and avoiding big swings within it, does more to protect the floor than hitting any single exact number. A cheap hygrometer is a worthwhile investment if you want to track this rather than guess at it.
How to keep your floor's movement under control
- Ventilate for short periods rather than leaving windows open all day in summer. Around 15 to 20 minutes of fresh air circulation is usually enough to manage humidity without letting the room get damp.
- Add moisture back into the air in winter. A humidifier is the most reliable option, though a bowl of water left near a radiator can help in a pinch by evaporating slowly as the heating runs.
- Avoid extreme, sudden changes in room temperature, such as leaving heating off for long periods and then cranking it up, since rapid shifts stress the wood more than a gradual seasonal change does.
- Leave the expansion gap around the room's perimeter alone. This gap is left deliberately during fitting, usually hidden under skirting boards, specifically to give the floor room to move without pushing against the walls.
- Don't sand or refinish a floor while it's visibly swollen or cupped. Wait for it to dry out and settle first, since sanding it in a swollen state can leave the boards uneven once they contract back down.
Does engineered wood move less than solid wood?
Yes, engineered wood is built from cross-layered plies under a hardwood veneer, which makes it noticeably more dimensionally stable than solid wood through the same humidity swings. It still moves to some degree, since the visible layer is still real wood, but it's far less prone to the wider gaps and loose blocks that solid parquet can develop over time. This is one of the reasons we recommend engineered wood for areas that see bigger swings in temperature and moisture, such as hallways near a front door, which we cover in more detail in our guide to engineered wood fishbone parquet flooring.
If your floor's movement seems more than seasonal, or you'd like advice on keeping a new installation stable through its first year, our team can take a look. Get in touch for a free quote, and we're happy to advise on what's normal for your specific floor, or contact us about commercial parquet floor fitting if the space in question is an office, restaurant or retail unit.
Frequently asked questions
Will my new parquet floor move more than an older one? It can, particularly in its first year, since newly fitted wood is still settling into the humidity of its new environment even after acclimatising before installation. Movement generally becomes more predictable once the floor has been through a full annual cycle.
Can underfloor heating make this worse? It can if it's not managed carefully, since it dries the air near the floor more than ordinary heating does. Engineered wood and a glue-down fitting method are generally recommended for underfloor heating for exactly this reason.
Should I worry if I hear creaking as the temperature changes? Occasional creaking as boards expand and contract is usually harmless and simply the wood settling. Persistent, loud creaking from the same spot is more often a subfloor or fixing issue and is worth having checked.
Do all wood species move the same amount? No, some species are more dimensionally stable than others. Oak is a fairly stable, popular choice for this reason, while some exotic or wider-plank species move more noticeably with humidity changes.
Is it worth using a dehumidifier in summer as well as a humidifier in winter? In most UK homes, a dehumidifier isn't necessary, since summer humidity rarely reaches damaging levels indoors. It's worth considering only if you're in a particularly damp property or notice humidity consistently running high on a hygrometer.
