Expansion and contraction should be factored in when installing composite decking because the material can expand and contract with changes in temperature and humidity. Composite decking is made of a combination of wood fibres and plastic, which can react differently to environmental changes.

During hot weather, the composite decking can expand, and during cold weather, it can contract. If the decking is not installed with enough space for this expansion and contraction, it can cause the boards to buckle, warp, or crack. This can lead to an unsightly and unsafe deck surface.

To prevent these issues, it’s essential to leave a gap between each board when installing composite decking. The amount of space needed will depend on the specific product being installed and the climate in the installation area.

By factoring in expansion and contraction during installation, you can ensure that your composite decking looks great and remains structurally sound for years to come.