Does Composite Cladding Expand & Contract?

When adding cladding panels to your house’s exterior walls, one of the primary considerations, apart from the look and how many boards you will need, should be whether or not the material expands and contracts and, if so, how much.

This is an essential factor to consider in the installation of your cladding panels, as it determines the number of boards as well as the distance between each board in order to allow for expansion.

In this article, we cover important facts about expansion and contraction and provide you with important advice regarding the properties of composite cladding boards and how to install them properly.


What are Expansion and Contraction?

At this stage, you are probably wondering what exactly expansion and contraction of cladding panels is and asking yourself, “is composite cladding prone to behave in a similar way?”.

Expansion and contraction of cladding boards or decking material happen when the material is exposed to extreme temperature changes and high humidity. It describes the movement of materials, i.e. the growth or shrinking of materials along the edges.

This is especially the case with traditional wood cladding boards as they are very prone to absorbing moisture, which causes the expansion of the material. The exact opposite – contraction – appears as soon as the wood has been lacking moisture.

The same goes for high temperatures. Any material that is exposed to a very hot temperature will expand. How much it will expand depends on the material.

Temperature change actually happens throughout the day, from cooler temperatures during the night to warmer temperatures during the day. This basically means that any building materials are always exposed to changing temperatures.

The UK has a lot of fluctuating weather conditions with ample amounts of rain, followed by blazing sunshine; it is, therefore, important to consider that your cladding boards will likely expand and contract.

Most materials do expand and contract in a similar manner to wooden boards; however, they might not do it in such an extreme way. Composite cladding boards, for instance, are waterproof and therefore expand because of a change temperature unlike wood cladding which absorbs water and expands and contracts a lot.

Composite cladding expands because of a rise in temperature. On top of that, this expansion is not as drastic as the way wood expands and therefore does not have to be of similar high concern for builders, but it also should not be disregarded.


Installing Composite Cladding Boards correctly

In order to prevent your composite cladding boards from distortion due to expansion, it is important to consider the size in which your cladding will expand when installing composite cladding on your house wall.

The best way to prevent composite cladding boards from distorting and warping due to temperature change is by installing composite cladding with an expansion gap.

Expansion Gap

In order to install composite cladding the correct way, you need to leave a gap between the composite cladding panels or where a composite cladding board meets a wall. This way, you prevent your composite cladding boards from warping or distortion.

It is advised that you leave a 3mm to 5mm gap between your composite cladding boards to allow your composite materials to grow or shrink. This also applies to other items which will be permanently installed next to any of your composite boards. Please review our expansion and contraction table that can be found in our cladding installation guide.

Nails & Screws

Another item worth considering is the size and placement of nails and screws when installing your composite cladding. As composite cladding expands, it might move the nails and screws back up, which can not only cause damage but is also a safety hazard.

Using the correct tools

When installing your composite cladding, make sure that you are using the appropriate tools when installing your composite deck boards. Here is what you will likely need:

  1. Spirit Level
  2. Measuring Tape
  3. Saw
  4. Drill
  5. Gloves



Here are some more important facts about expansion and contraction that will likely help you when wanting to install cladding at home.

Why does composite cladding expand less than timber?

Out composite cladding is made out of a special composition of polythene from recycled and reclaimed wood fibres that has been treated under a lot of pressure and is then sealed with a polymer layer in order to make it waterproof.

As these composite cladding boards are now water repellent, they cannot absorb any moisture and expand and contract due to any changes in humidity or heavy rainfall. This means that they contract and expand way less than traditional timber, as it is more prone to absorbing high levels of moisture and therefore expands a lot more.

However, composite cladding will still expand and contract due to temperature changes.

Why is it important to consider expansion and contraction?

If you haven’t put the expansion and contraction into consideration before installation of your composite cladding by calculating for enough room, i.e. adding an expansion gap, your boards will expand and press against one another until they warp.

This does not only apply to composite cladding but also to other composite materials such as composite deck boards and especially for real wood. Even treated wood does expand and contract.

Why do I need to install battens between the wall and the composite materials?

In order to prevent composite cladding from getting in contact with your house wall and potentially trapping moisture that can be damaging to your home’s exterior, installing a flat piece of wood in between the composite cladding and the wall is essential.


Closing Thoughts

Does composite cladding expand and contract? Yes, due to temperature changes, your composite cladding material will definitely grow and shrink along the edges.

However, composite cladding is not as prone to this process as wood and is, therefore, a better choice when considering the installation of cladding on your house. On top of that, the expansion gap you are required to leave is not nearly as wide as with traditional wood.

Choose from a wide range of Ecoscape composite cladding boards for your house’s exterior, and ensure that your materials will not be as heavily affected by a change in temperature to prevent any potential warping or damage to your house’s facade and cladding material!

With our extensive range of composite finishes, you won’t even have to abstain from having traditional wood cladding but can say goodbye to any other downsides of traditional timber, as our boards come with timber-inspired wood finishes, too.

Gary is the founder and CEO of Ecoscape UK. Gary graduated from Liverpool JM University in 2007 with a 2:1 in Economics. A passion for innovation, design and sustainability, Gary has put to market numerous wpc products/systems, some of which have UK and European registered designs. Outside of work Gary enjoys spending time with his family, the great outdoors and watching Manchester United.