The UK timber cladding market is growing, providing many additional sales opportunities for merchants and contractors alike. Bernie Roberts, National Product Manager for Cladding Solutions at International Timber, reveals the latest cladding trends and how to correctly specify and install timber cladding.
The timber cladding market in the UK is set to enjoy a growth rate of 4% by 2027, with increased demand in both residential and non-residential construction driving market growth. Ever since the start of the pandemic homeowners have been looking to refurbish and improve their properties, with timber fast becoming the go-to product due to its cost-effectiveness, durability and sustainability.
What is cladding?
Cladding is the application of one material over another to create a ‘skin’ or outer layer. In construction, cladding is used to provide a degree of thermal insulation and weather resistance to a building, and to improve its appearance. Cladding can be created using a wide range of materials, with timber cladding proving particularly popular in recent years.
Rainscreen cladding – also known as splayed or rhombus cladding – is a form of weather cladding designed to protect against the elements, that also offers thermal insulation. The cladding does not itself need to be waterproof, as it is merely a control element; it may serve only to direct water or wind safely away in order to control run-off and prevent water infiltrating into the building’s structure.
Cladding may also be a control element to prevent noise either entering or escaping. It’s also important to remember that cladding can become a fire risk, either by design or material. Merchants should always remind their customers to double check that the cladding they install will provide adequate drainage and ventilation, as well as being fire retardant.
Why use timber cladding?
Given the importance of Environmental Product Declarations (EPDs), it’s not surprising to find that people are increasingly keen to work with sustainable products. In fact, there has been a growing realisation of the need to use more natural and low-carbon building materials such as timber in recent years, with more builders and contractors adopting this line of thinking.
Timber cladding also brings an attractive aesthetic to a building if fitted correctly and maintained effectively. Timber is unique and each piece is different, so it can quickly and easily be rejuvenated to alter its appearance.
As well as being economically priced and extremely durable, timber cladding also offers increased thermal insulation over other building materials. Timber is easily worked and the fire performance of timber can be improved through factory-approved treatments, such as impregnating the raw timber with suitable a fire-retardant product.
The species, profile and additional coating options available around timber cladding are all things to consider before making a purchase. Softwood, hardwood and modified timbers all play a part in the design stage, and we recommend a 10% wastage allowance on all cladding timbers (up to 15% on Thermowood).
Once a profile has been chosen, the timber should be durable enough to meet the service life required. Where the natural durability of the timber species is not good enough, a wood preservative, factory impregnation or a modified timber should be considered.
Many timbers can be left uncoated to weather naturally to a silver-grey colour over time, but elevation should be considered. A northern elevation will not get as much exposure to the elements as a south-facing elevation, so a southern elevation will require more maintenance if the cladding is coated.
What about coatings and fixings?
Coatings offer the cladding both water repellence and UV protection. The darker the colour, the more pigment and the more the protection against UV degradation, whereas clear coatings offer less protection. All coated cladding requires end-grain and fixings to be sealed to prevent moisture ingress. This is because timber is hydroscopic and will take in and expel moisture as the humidity around the timber increases or decreases.
We suggest that if any profile is to be coated, the leading edges have a slight round on them to aid with coating adhesion. Similarly, it is recommended that timber requiring fire treatment is done in controlled conditions and by an approved factory application. The use of site brush or spray applied fire treatments are not approved by the Wood Protection Association (WPA), as these may not provide sufficient protection.
Finally, it is recommended that any fixings are made of a non-corrosive material such as stainless steel, which is ideal for all timber species. Other materials may cause permanent black spotting and corrosion staining to the surface of the cladding.