Why Does Composite Decking Need Spacing During Installation

M. John
composite deck installation

Ultradecking composite boards are the most desirable material used in making decks because they are long-lasting. However, when installing composite decking, it is important to follow the right procedures to make the decking look good and last long. One of these guidelines is to ensure that the composite board is properly spaced during installation. But why does composite decking need spacing during installation?

composite deck installation

Why Composite Decking Need Spacing

Composite deckings are affected by temperature change in the environment. The decking needs spacing because it expands and contracts when there is a temperature change. In hot seasons, when the temperature is at its peak, the composite board expands along the length and its width.

If you space the composite decking properly during installation, it will ensure that the boards are not shifted from their original position when there is a temperature change. A high temperature can cause the composite decking to increase in volume if there aren’t enough gaps between the decking. Thermal expansion can weaken the composite boards, thereby reducing their lifespan.

But, when there are gaps between the boards, it allows the wood-plastic composite to expand without buckling. Spacing the wood-plastic board is also vital because aside from the fact that composite decking expand, it also needs space for proper airflow and water drainage.

Factors That Affect Composite Decking Spacing

Why Does Composite Decking Need Spacing During Installation

Some factors influence composite decking spacing. They are heat, the colour of the composite decking, and the location of the decking.


A good reason why composite boards need spacing is that they absorb heat from the sun.  Composite boards consist of materials like wood fibres and recycled plastics. In hot regions where the temperature is usually high, thermal expansion of the composite deck can happen. It is because the plastic material in the composite decking makes the board absorb heat from the sun. When this happens, the composite board expands at all sides and can shift from its original position if there isn’t enough spacing between the deckings.

Location of the Decking

The location of the composite decking can affect its expansion. Decking installed outdoors in the garden or lawn are completely exposed to sunlight which will absorb a great amount of heat from the sun. The heat absorption will make the decking expand and increase in volume.

But those installed on the balcony are shaded from direct sunlight; they tend to absorb less heat. If there is no spacing between the outdoor decking, it will shift from its fixed position when it expands.

Colour of the Composite Decking

The composite decking colour can also impact how the decking widens when it is exposed to sunlight. Generally, darker colours tend to absorb heats from the sun than lighter colours. If your composite decking board is dark in colour, there is a high possibility that the decking will expand more. It  will expand more when the temperature is hot when compared to a light-coloured composite board. To prevent the deck from absorbing heat from the sun, you should use a light-coloured composite deck in hot regions.

Composite Decking Spacing

If you want to install a wood-plastic decking in your home, there should be enough gaps between the deckings. Also, the space required between the boards will depend on the climate condition in your locality. The number of spaces between the deckings will be higher if you live in a hot region than a cold region.

When installing the composite board in your home, you should ensure that the board does not meet tightly at both ends. Ensure to leave a space between the wood-plastic composite to allow for expansion and contraction of the decking. You can also attach fasteners in the middle of the decking to prevent it from shifting when it expands.

Composite decking makers recommend that there should be at least a gap of 5mm between the ends of the composite decking. When installing composite decking in your home, ensure that a gap of 5mm is between the deckings.


Composite decking needs spacing during installation to give room for expansion. A high temperature can cause the decking to sag if there is inadequate spacing between the deckings. Composite decking makers, therefore, recommend that there should be a gap of 5mm between the deckings.


Tags: Deck installation, Spacing decks

Leave a Comment

Shopping Cart