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Does Wood Expand In Winter Or Summer?

02 August 2023 min read

How does the weather and the changing seasons influence wooden furniture, carvings and other timber projects you've created?

Wood is an incredible working material capable of producing everything from professional homeware to creative artwork and sculpture. However, choosing the right wood for any project is essential and will determine the successful outcome of your finished work. Selecting an appropriate interior or exterior wood is also important due to its suitability and resilience to certain conditions.

Debate continuously circles around what exactly causes the expansion and contraction of wood. Many opinions point towards seasonal variations, temperature changes and even moisture - but what actually causes wood to warp?

In this blog, Woodshop Direct break down exactly what causes wood to alter in certain environments and why it happens.


What Causes Wood To Expand & Contract?

The central factor in wood expansion and contraction is moisture. All wood, whether it is still part of a living tree or felled for woodworking, has a moisture content. Therefore, wood can take on more moisture and it can also lose moisture. However, it will always contain a level of moisture within its composition of fibres, cavities and tubular cells.

In expansion and contraction, the secondary factor to moisture is temperature. For example, if temperatures increase in drier weather conditions the moisture will evaporate from the wood's cell walls. This may cause initial thermal expansion and potential warping, swelling and distortion as it heats, but shrinking can also occur in the long run. Temperature alone will not cause wood to swell or shrink, it's the humidity in the environment and the moisture content of the wood that determines the movement. By how much your wood expands or contracts also depends on the wood species in play.


Does Wood Expand In Winter Or Summer?

Although wood expansion and contraction is caused primarily by moisture and subsequently by temperature, the impact of seasonal changes are complicated owing to the UK's incredibly changeable weather conditions. However, the same rule remains true: the greater the moisture content of the wood, the more likely it is to expand in the right conditions.

When analysed in isolation, wood appears to contract in the cold. But when taking into account the UK's relatively high humidity levels compared to that of continental Europe, and considering that Britain typically experiences twice as much rain in the winter than in summer; these combined factors will likely contribute to wood expansion when exposed to common winter conditions. Humidity also peaks in places such as London over December, which could also cause your exposed timber to expand.


How Can I Counteract Wood Expansion & Contraction?

It's important to establish that all wood reacts to its environment in different ways. At Woodshop Direct, we allow you to Shop By Use; choosing from an array of different timber materials for interiorsexteriorsjoineryprofilesdoors and furniture. You'll also find a number of different sheeting materials specifically designed for marine or moisture-prone areas