With a focus on the manufacturing processes, Steve Wright, Chairman at George Barnsdale explores some key factors affecting the longevity of a timber window and door, and what can be done to prolong their lifespans.
The robust nature of wood, combined with modern preservative treatments, allows timber windows to withstand the test of time, maintaining their structural integrity and design far longer than many synthetic alternatives. Not all timber windows and doors are created equal and there are various factors that can influence the longevity of your timber window including material choice, manufacturing processes, correct installation, and maintenance.
Monitoring moisture content
One key factor that affects timber’s long-term durability is whether it remains dry or not. If timber remains dry (usually deemed a moisture content of less than 20%) it will not become rotten. The acceptable moisture levels of timber depend on its final use and the average relative humidity of the environment it will be situated in.
Ideally, timber should be processed at around 12% moisture content as the moisture content in the UK oscillates between 12-16% depending on the weather and climate. Most timber used nowadays is engineered, which makes it more stable, and therefore easier for coatings to be applied and to be maintained. But if you’re laminating timber, it needs to be around 12% moisture content. The ambient moisture content in a store and a heated factory will dramatically reduce this unless the atmosphere has the moisture controlled.
Combining design and performance
Design is about creating stunning windows that perform to the highest levels possible. Constantly developing timber products to ensure they perform to the highest standards possible ensures that the design of the window is optimised, whilst refining techniques that ensure the timber performs effectively.
To influence the design and performance of timber windows, you can concentrate on preventing water ingress by incorporating things like internal beading, which research has shown significantly extends the life of a timber window. You can also make small profile adjustments to ensure they discard water as easily as possible. The design and assembly of joints also influence the long-term performance of the paint finish as timber moves depending on temperature and humidity. If a joint fails, there needs to be a secondary line of defence. This can be achieved by carefully sealing all the unexposed joints, allowing them to be protected even if the joint fails. Consistently developing timber products can help understand any changes that need to be made to coatings to ensure they perform to the highest standards.
Having a thorough paint process
To allow coatings to last for decades, there needs to be a very good bond between the coating system and the substrate. This cannot be achieved by spraying directly onto the substrate as the paint does not penetrate deeply enough. To ensure this doesn’t happen, a 2-coat flow coating system can be used, which deluges the product and goes into a very high humidity area to stop the paint drying too quickly and to allow it to penetrate deep into the substrate. Any exposed end grain should then be sealed, and a special sealant applied to all V joints, allowing the joints to move without cracking the final coating.
How can you ensure your timber windows will last?
As we have explored, a very well designed and manufactured timber window and door will stand the test of time with very little maintenance, but to ensure your timber window lasts longer, simple inspection and maintenance will help reduce the likelihood of expensive maintenance in the future.
There are various ways to maintain your timber window to ensure its longevity. For instance, it’s important to make sure there is no build-up of algae or moss-type organisms on your window, as they can penetrate deep into the coating. This is more likely to occur on north-facing elevations. To prevent this from happening, you can use diluted household bleach on areas where algae may be starting to form.
You should also check for cracks in your windows, particularly on joints. They are simple and cheap to rectify and will dramatically reduce the re-coating period if dealt with efficiently. It is important to choose the type of timber for your window wisely. We would recommend opting for an engineered timber, such as Accoya. The substrate in Accoya is more stable and the thermal performance is better. Accoya will also provide the best long-term paint performance.
What makes a George Barnsdale window last a long time?
We have spent decades researching and developing our timber windows to ensure they meet the highest industry standards. Our on-site R&D centre allows us to constantly innovate to perfect our paint systems using our own QUV accelerated test chamber and test our timber windows and doors against weather or security conditions. This extensive research allows us to develop our products and systems for optimum long-term performance.
As a building material, timber provides many benefits that allow it to perform to the highest standards whilst providing the design flexibility to replicate even the most unique specifications. Timber windows – if manufactured with longevity in mind and maintained throughout their lifespan – will last for 60 years or more.
Do you have an upcoming timber windows project? To find out how we can support you and your timber window requirements visit: https://pages.georgebarnsdale.co.uk
