Timber window frames are naturally beautiful, durable, and environmentally friendly, but they require a little more thought and forward planning to keep them in perfect condition. Although timber frames always need a little TLC every now and again to keep them looking their best, weatherproofing can significantly extend their lifespan and increase their strength, resilience and suitability – even in extreme environmental conditions.
Properly designed and treated windows benefit trade clients in a number of ways – and in most cases, weatherproofing makes the sought-after aesthetic and environmental credentials of timber a possibility in commercial construction projects, too. When longevity and prolonged performance are key concerns, there are a few important considerations to be aware of, from timber selection and frame design to maintenance requirements. With the enhanced protection weatherproofing brings, here we explore how timber can be a robust and durable option even in the most extreme and diverse climates, with specialist advice on types of timber and treatments available plus design and maintenance tips.
Types of timber suitable for extreme climates
Certain types of timber are better suited to extreme climates than others – so it’s important to consider this when planning and designing bespoke frames. Some types of timber can remain in-situ for well over 60 years, but there are also many less durable timbers that may only have lasting power of 15-25 years. Typically, softwoods have a shorter lifespan and are more prone to weathering over time than durable hardwoods – but hardwoods often come with a higher price tag to reflect this.
Timber itself is well-suited for external construction, which is why it’s been used as a building material for centuries. Timber’s natural resilience and resistance to the elements make it an excellent choice in any climate. Wooden windows sometimes get a bad rep for being a less durable option than aluminium and uPVC – but this often comes down to the type of timber used or a lack of proper maintenance over the years. In harsh climates, some timbers can withstand years of wet, cold weather, including frost and ice.
Hardness, pest and rot resistance and the shape and configuration of window frames are all key factors when assessing timbers for extreme weather suitability – and many timbers naturally possess these characteristics in varying degrees. The key, then, is to source a timber that perfectly balances the practical performance and aesthetic you’re looking for. This is a discipline woodworkers have practiced for hundreds of years, but now we have scientific insights that enable us to assess and understand the protective properties of different types of timber fully.
Every timber is given a durability class based on its ability to withstand the elements, rated from 1 to 5. Factors taken into consideration include strength, resistance to decay and rot and how the timber responds to exposure to the elements over time. Cedar, European Oak, Iroko, Ipe, Teak and Black Walnut are all excellent choices when selecting timbers for extreme climates, with Cedar, Teak and European Oak being the most commonly used for external applications here in the UK.
Protective treatments and finishes
Making the right timber selection is key – but no matter which type you use for your construction project, there are a variety of protective treatments and finishes available to further extend the lifespan of your wooden window frames.
Treatments vary in cost and the benefits they offer, as well as the formulas themselves. Some offer a practical benefit by also acting as a barrier between your timber and the elements, such as varnishes, stains and sealants, which protect the timber from moisture and UV radiation. Other chemical treatments protect timber from rot and pests, which once set in can severely impact the integrity and function of your window frames. These tend to be made from chemical cocktails or can also be biocidal cleaners, which although highly effective may not align with those who have environmental or health concerns. In these cases there are a growing number of natural, more sustainable options available – including copper-based formulas and vapour permeable membranes which also reduce condensation and inhibit mould growth.
The treatment process may include several stages, including undercoat wood preservatives and coatings, sealants and varnishes. Timber treatments are usually best applied by a professional and may need to be reapplied periodically – usually every 10 years or as soon as you start to see signs of damage or wear and tear.
Design considerations for weatherproofing
Most trades know that timber needs a little extra TLC – but you may not be aware that the design and configuration of your timber frames can influence how long they last. This is a crucial consideration for developers, architects and homeowners alike, as it’s an innovative way to further improve the longevity of your wooden window frames.
There are a few essential design elements to be aware of that contribute to the weatherproofing of your timber frames. Certain features lend themselves to protecting the external fabric of your property, preventing the damage caused over time by water slowly seeping in. Frame thickness, joint types (such as mortise and tenon), and even glazing selection can all impact durability, as these can either prevent or perpetuate issues such as water ingress and damage and rot. Proper drainage and physical water protection is essential to keep your windows protected from weather damage – and there are a variety of ventilation and drainage systems available which can be integrated within your window frame design to improve its weatherproofing. It’s useful here to understand and apply the 4Ds of waterproofing – which can be applied to various projects in construction. These principles (Deflection, Drainage, Drying and Durability) can be employed within window frame design to help ensure enhanced protection and a longer lifespan for your timber windows.
Maintenance practices for longevity
There are a number of essential maintenance practices to be aware of when extending the lifespan of your timber window frames in extreme conditions is a concern. Timber gets an unfair reputation for being difficult to maintain and more prone to wear and tear than alternative materials – but in reality, timber is much longer lasting and regular maintenance is fairly easy and inexpensive.
Simple cleaning steps are a great start – removing dust build-up, checking for damage and gently washing the frames with a little mild soapy water and a soft cloth (or as per the manufacturer’s instructions). This task can be done yearly (or more often if you can) and enables you to keep your windows looking in good condition, functioning optimally and preventing any potential problems from becoming too big to manage. It also keeps bugs and pests at bay and allows you to identify where any rot or dampness may have started to set in. When your windows are facing extreme weather conditions it’s advisable to repeat this process every few months where possible.
Cleaning at regular intervals also offers the opportunity to inspect your timber window frames for early signs of damage or wear. When picked up sooner rather than later, these issues can easily be remedied or repaired at a much lower cost than with more extensive remedial work or replacement. Pay special attention to moving parts – as these are the ‘weak spots’ within any timber frame. Check that moving parts aren’t sticking or compromising the wood, and inspect seals to ensure they aren’t perished in any way that could leave the surrounding timber unprotected from the elements.
The frequency of maintenance and treatments depends on a number of factors – including the type of frames and their placement in your property, the environment you live in and the specific products used. Different treatments and coatings have varying intervals for re-treatment, so always be sure to read and follow the manufacturer’s recommendations for his.
Ensuring longevity and durability for timber window frames in extreme climates
In this guide we’ve provided some comprehensive steps and plenty of tips and tricks of the trade to keep your windows in the best possible condition for many years to come – even in the most extreme climates. There isn’t a ‘one stop shop’ solution to weatherproofing – instead, you’ll need to employ a combination of the practices above collectively to ensure that you achieve a level of protection that’s right for the environment and level of functionality required. From timber selection and design to choice of glazing and treatment, considering these factors as early on as possible in a project is crucial, as many of them must be planned and prepared for in advance and can influence other design and construction features of a property. If you’re new to working with timber or weatherproofing and aren’t sure where to start, enlisting expert support is essential. Speak to our team of expert joiners today for tailored advice.
