What environmental factor causes materials in construction to change in size?

In construction, one of the primary environmental factors that causes materials to change in size is temperature changes. Materials, especially those like wood and certain metals, tend to expand when heated and contract when cooled. This physical property is known as thermal expansion and contraction. For instance, as temperatures rise, wood can swell, leading to issues like warping or splitting, while lower temperatures can cause it to shrink. Understanding how temperature affects materials is crucial for ensuring structural integrity and avoiding issues during installation or over the lifespan of a building.

Humidity levels also influence material size, particularly in wood, which can absorb moisture and expand or release moisture and contract. However, temperature changes are more universally applicable across a broader range of materials in construction, making them a critical factor to consider in design and construction processes.