Composite cladding is manufactured with composite material. Composite material is a highly resistant and durable exterior material to add to your outdoor space. Although composite cladding is highly water resistant, it is not completely waterproof.

This is due to its composition of both plastic and wood fibres mixed together, which produces the appearance of timber with all the added benefits of plastic material. The recycled wood fibres in the material are what make it not completely waterproof. 

In general, composite cladding is designed to be water-resistant, offering better protection against moisture compared to traditional wood cladding. The plastic component in the composite helps repel water, reducing the risk of rot and decay that can occur with natural wood. 

The wood fibres in composite cladding can still absorb water to some extent, but the overall design aims to minimise this absorption. Manufacturers may use various methods to treat the wood fibres, making them less prone to swelling or warping when exposed to moisture. This treatment contributes to the cladding’s ability to withstand different weather conditions.

Levels of Water Resistance

The waterproofing of composite cladding depends on its composition and the manufacturing process. There are different types of composite cladding for example; first-generation or second-generation composite cladding. Second-generation composite is also referred to as ‘capped’ composite.

Capped composite cladding is more resistant to moisture and the elements in comparison to uncapped composite cladding. This is due to the additional layer of plastic covering the board, which acts as a shield and further protects the surface of the board from moisture, fading, staining, etc. 

Higher-quality products often undergo rigorous testing to ensure they meet specific standards for water resistance. Therefore, when considering composite cladding, it’s advisable to check the product specifications and certifications provided by the manufacturer.


Installation also plays a crucial role in the waterproofing performance of composite cladding. Properly installed cladding with appropriate sealing and flashing can help create a more watertight barrier, preventing water infiltration into the underlying structure.

It’s essential to follow the manufacturer’s guidelines and recommendations for installation to maximise the cladding’s waterproofing capabilities.

Despite the water-resistant features of composite cladding, periodic maintenance is advisable to ensure its long-term performance. Cleaning the cladding regularly and inspecting for any damage or wear can help identify issues early on and prevent potential water-related problems.

  • Ventilation and Drainage:

Adequate ventilation and drainage are crucial elements in preventing moisture-related issues. When installing your composite cladding, you must pay attention to the design of the cladding system, ensuring that there is proper ventilation to allow air circulation. Additionally, incorporating effective drainage mechanisms helps channel water away from vulnerable areas.

  • Follow Manufacturer Guidelines:

Adhering to the specific instructions and guidelines provided by the manufacturer is imperative. Each composite cladding product may have unique requirements for installation, and deviating from these recommendations can compromise the waterproofing performance.

  • Gradient:

Ensure there is always a gradient and that the cladding is never just flat vertically, as this will cause water to pool on top of it, causing moisture staining and issues regarding structural integrity.


In summary, composite cladding is designed to be water-resistant, thanks to the combination of materials and protective measures taken during manufacturing.

However, the specific waterproofing capabilities can vary between products, and proper installation and maintenance are crucial factors in ensuring the cladding’s effectiveness in repelling moisture. When selecting composite cladding for a project, it’s essential to consider the product’s specifications, and certifications, and follow the manufacturer’s guidelines for installation and maintenance.

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