How to Maximise Your Timber Cladding’s Longevity

Timber cladding remains a popular choice in both traditional and modern architecture, offering a unique blend of natural beauty and tactile appeal. With the right approach it can provide decades of performance. Longevity, however, depends on four key factors: material choice, design detailing, installation method and ongoing maintenance.

Selecting a timber species

The first and arguably most important decision is selecting a timber species suited to your project’s environment and desired lifespan. Options such as Canadian Western Red cedar and larch are popular due to their natural properties that provide durability without the need for additional treatment. When installed with adequate ventilation and correct detailing, these timbers can last over 30 years, even when left uncoated.

For enhanced durability, modified timbers offer a reliable alternative. Products like ThermoWood Ash and Accoya undergo processes that significantly improve resistance to decay, achieving Class 1 durability. These species are particularly well suited to exposed environments as their enhanced stability makes them far less prone to cupping, splitting or warping. This also makes them an excellent choice for finishes that need a stable base to perform well.

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Factory applied timber cladding coatings

Left untreated, all timber will weather to a silver-grey (this does not affect the timber’s performance, provided it has been correctly detailed). For those after an aged look, pre-finished wood products like Accoya Color Grey deliver an instant weathered aesthetic. Alternatively, accelerators such as the OrganoWood treatment protect against rot and fungal decay while encouraging timber to develop a uniform patina – an effective option for low-maintenance projects.

This project features naturally durable Canadian Western Red cedar cladding. Left uncoated, it will weather beautifully over time to a soft, silver-grey patina

Where conserving colour is a big priority, a wide variety of coating systems are available to suit a whole host of aesthetic goals. Although these finishes don’t extend the lifespan of the timber, they do offer excellent surface protection against UV degradation, discolouration and adverse weathering. Millworks’ factory-applied MillCoat wood stain, for example, provides a breathable and durable protective layer while allowing the timber’s natural grain to remain visible.

It should be noted that medium-movement species, such as larch, benefit from lighter finishes, as darker colours absorb more heat, increasing the likelihood of movement. Choosing the right coating and ensuring it’s applied under controlled factory conditions can enhance its performance.

Achieving a lasting exterior finish

Even with premium timber and coatings, careful installation and design detailing is essential. It’s advisable to use a fixing system that avoids penetrating the face of the wood. Secret-fix solutions, such as the Grad x Millworks system, secure boards from the rear using clips and aluminium rails, preserving the timber’s surface and reducing water ingress points.

Moisture is timber cladding’s main enemy, so preventing prolonged exposure is key. Cladding should always be installed with a gap above ground level and include design features such as splashback detailing, roof overhangs and well-positioned trims and flashings to guide water away from the building.

The Grad x Millworks secret-fix system secures timber boards from behind using pre-spaced clips, maintaining the integrity of the finished facade

Cladding profiles should be chosen to encourage water run-off and minimise the risk of potential water traps. During installation, adequate expansion gaps between boards are essential to accommodate natural movement caused by humidity.

Maintenance plays an ongoing role, too. Choosing a coating system designed for ease of reapplication, such as water-based stains that fade gradually, will simplify maintenance. Millworks’ MillCoat, for instance, can be reapplied with minimal surface preparation. Regular inspections and cleaning will help identify early signs of wear, and recoating before finishes visibly degrade ensures protection and avoids costly remediation.

Steven Newman Steven Newman is the founder of Millworks. He shapes the company’s values with a passion for research, development and long-term investment. Through prioritising innovation and quality, Millworks combines advanced engineering with strong knowledge of timber behaviour, delivering high-performance solutions that support self builders and renovators. For guidance on selecting the best cladding and installation system for your project, get in touch with the team by heading to the Millworks website or call 01223 967733.