Do Low Maintenance Timber Windows Really Exist?
Can timber windows really be low maintenance? Bereco’s General Manager Nicola Harrison discusses homeowners concerns around timber windows maintenance and decoration.
When purchasing timber windows one of the most common questions I am asked by homeowners is how often will I have to decorate my windows and how long is the paint actually going to last?
The reality is that there is no definitive answer to this question as many factors need to be considered such as house design, fitting method, exposure, finish type and colour but in an effort to reduce this and define this period there are things that both homeowner and manufacturer can do to ensure that the time period in which redecoration is required is significantly extended.
The responsibility for the durability of the windows is not only on the homeowner and the need to maintain the windows after installation; but the longevity of any timber window or door relies heavily on the manufacturer to adopt best practices in the selection of timber, design, construction and in factory finishing of timber windows and doors.
Timber types used in the manufacture of timber windows and doors not only affect the total service life of the joinery but also the paint system and its durability. There are so many types of timber on offer which one do you choose?
Over 90% of the wood we use in construction is softwood from European forests. Timber windows and doors in the UK are generally manufactured from redwood pine; a softwood grown in Scandinavia. Scandinavian redwood is slow growing, high quality it has a high proportion of heartwood; and small knots and achieves excellent durability even without preservative treatments.
Hardwoods are available and are often chosen for their decorative appearance when a translucent or stained finish is specified.
Choosing the wrong type of timber can compromise a windows functionality, strength and durability so as a purchaser you should always choose a durable timber species that comes from a well-managed forest with FSC / PFEC chain of custody certification.
Design features such as sufficiently sized glazing rebates appropriate to the type of glazing; carefully designed drained and vented glazing systems that prevent water accumulation; rounded frame edges (min 3mm radius), sloping cills (min 7 degree fall), and glazing beads designed with water drain off in mind are all key to the service life of any timber window or door.
The British Standard BS644 (Fully Finished Factory Assembled Windows – Specification) defines these design features and a manufacturer that can prove compliance through third party certification or at a minimum by test to BS644 is a must.
Construction of the windows and doors is key to the longevity of external joinery; all joints must be appropriately and robustly constructed with any fixings concealed below the surface of the timber. Where separate drips and cills not part of the main frame construction these should be fixed using screws on a concealed part of the cill i.e. not through its face.
A manufacturer that preservative treats its timber and controls the moisture content of its timber will also enhance durability and longevity of their product over those that don’t. Keep it simple and ask to see samples as evidence of robust construction methods and ask about moisture control.
Factory Finishing is now common practice for many manufactures of timber windows and doors. The painting or staining process being fully incorporated into the production facilities where windows and doors are made. Long gone are the days of windows being supplied with just a basecoat for on-site coats of paint; the cost of factory applied coatings from a manufacturer with fully integrated paint facilities is now comparable if not cheaper to that of employing decorators to hand paint your windows.
With factory coatings you get a finish applied in controlled conditions, no damp, no humidity, no brick dust, no dirt, just a clean smooth defect free finish.
Modern paint systems are also highly flexible they allow timber to do what it does naturally and expand and contract and they are resistant to direct weathering so always choose a paint system designed for external joinery and ensure your chosen manufacture is using one.
Modern paint systems are always applied in stages with most following a similar process of:
Preservative Treatment; penetrating deep into the timber the preservative treatment offers protection against rot and fungal decay, stabilises the timber against the risk of twist and warp and promotes even colour on final application.
Ensures the perfect surface for application of subsequent coats, even colour and deeper translucent stain colours on final coat application.
Intermediate Coat & Join / Grain Protection
Coating and sealing of end grain and v joints provides the timber their all-important protection from the elements, flexible joint sealants allows the timber to breath whilst leaving the coating unaffected by cracking.
Providing the products with their final weather resistant coating, and featuring UV absorbers to prolong the durability of the finish.
Another and key consideration is the choice of the colour of the finish of your windows as this will have a direct impact on the service life of your windows and doors. Dark colours absorb heat and in turn can degrade quicker so think about your choice of colour; stained finishes contain less pigmentation and in turn less UV protection so choose your priority be it the length of the maintenance cycle or the colour and finish of your windows.
Post Installation Maintenance
Post installation maintenance is a reality with windows and doors in general, not just timber windows and doors but also of those made from other materials such as uPVC and Aluminum. Whilst many claim ‘maintenance free’ read the small print and you will find a maintenance requirement in some form or another.
Timber windows and doors have historically had a bad reputation when it comes to needing painting and no-one wants to be faced with the daunting task of repainting windows and doors every summer but advancements in the manufacturing process that I have already discussed as well as those in the quality of the factory applied paint and stain systems today are already offering extended service lives of timber windows and doors.
So what can I expect to be doing in reality after installation? You can expect from a timber window and doors supplier today to have an annual or bi annual cleaning routine, with top coat redecoration not being required until between 8-10 years (opaque finishes) from delivery followed by a 5-7 year cycle from first redecoration and thereafter.
I would strongly urge the use of the care sets provided; most suppliers now offer a care set that should be used during routine maintenance some yearly, some twice a year. These paint care sets revive dulled paint, they restore the water repellent properties of the finish and offer the finish its UV protection; you wouldn’t sit in the sun for hours without sun cream with a suitable SPF factor so therefore you shouldn’t expect your windows to do the same if you want them to last.
So how do I ensure my windows will be low maintenance?
My advice is do your homework before any purchase; don’t be afraid to ask for evidence of performance and to see the maintenance and redecoration cycles during your supplier selection process; it is after all a big investment and one that you that will have to live with long after all the suppliers and builders have gone from your home. So;
- Choose a supplier that is member of a trade organisation such as the British Woodworking Federation (BWF) and the Wood Window Alliance (WWA) whose strict membership requirements and quality standards are higher than those of the timber window and doors industry in general and have to be achieved and proven in order to gain membership.
- Choose a supplier that uses durable timber types such as European redwood and that is responsibly sourcing the timber for your windows and doors (PFEC / FSC).
- Choose a supplier that can prove compliance with the British Standards (BS644) for peace of mind your windows have been designed with longevity a priority.
- Choose a supplier that can offer evidence of a controlled, measured and documented paint application process or even better that can provide independent third party accreditation.
- Ensure you have reviewed all the post installation and maintenance information from your chosen supplier so you fully understand what needs to be done after the windows are in and the builders are gone.
- Ensure you get a warranty from your supplier; one where action has to be taken i.e. repair or replacement should the coating show defects within the defined warranty period.
- Finally; follow the suppliers and or paint manufacturers guidance for maintenance and redecoration after installation it will make your windows look better and last longer.
So do Bereco meet all these criteria?
We do; Bereco are members of the Wood Window Alliance, all our windows and doors are available in either durable European Redwood (Scandinavian Pine) or Dark Red Meranti with full FSC chain of custody certification.
Bereco are engaged members of the third party accreditation body Exova’s Q Mark Schemes including; BS644 Window General Performance, The High Performance Timber Window Scheme, The Enhanced Security Window & Door Schemes (PAS24 for Part Q & Secured By Design) and the unique Paint Application Scheme that closely controls our paint and stain application processes and personnel applying the paint or stain to your windows and doors. Keeping you safe in the knowledge that someone independent of Bereco is verifying the quality and performance of our windows and doors.
Our extensive warranties include 30 years against rot and fungal infection & 10 years against defects in the factory applied paint finish to name just a few and our homeowner manual details in full the role of the homeowner in the maintenance and redecoration of our windows and doors after installation.
Heriot Watt Service Life Study
WWA The specifiers Guide to Timber Windows
WWA Maintenance Advice Note
Teknos Technical Manual – single pack joinery coating systems
British Standards BS644 – Fully Finished Factory Assembled Windows – Specification