Why choose timber windows?

There’s a feel-good factor

Olav Skretteberg of Broxwood, a forester and independent windows supplier, says people in the UK like timber. There’s a definite feel good factor about it. Sourced from managed forests- often from my homeland of Scandinavia- timber is an environmentally friendly, thermally efficient, good looking material.

Modern, factory-manufactured timber products, such as windows, are also proving themselves in terms of performance – offering durability, low maintenance and competitive cost.

Currently around 12 million windows of all types are sold each year in the UK, with timber windows accounting for 25% of that market.  57% of timber windows sold in Britain are used by the public sector and 42% by the private; 86% of these in refurbishment projects and 14% for new build applications. (Figures from FSC website.)

Over the last ten years in particular, the evolution of timber windows in terms of quality, durability and design has been dramatic, in response to both regulation and marketplace.  Factory finished and treated against rot, with frames which are fully protected from water and UV light, modern high-performance timber windows can have finish guarantees for up to 10 years and rot free guarantees for up to 30.

Dual sealing and factory glazing will help maximise the life of a unit and sophisticated design details, such as drained and vented glazing rebates, are used to prevent deterioration and lengthen the life of the timber

How long a window frame will last depends on many factors. The National Building Federation’s “Standards in Quality and Development” gives PVC windows an expectancy of 20 – 25 years where as it gives vacuum treated softwood 25 – 35 years. According to the Green Builders Digest, “well designed and well maintained timber windows can and do last the lifetime of the building in which they are installed”.

In addition, manufacturers are now producing timber windows that will take single, double and even triple glazed insulating glass units, to suit particular specifications, and capitalise on advances in timber technology.

STANDARDS & REGULATIONS
The main British Standard for timber windows is BS644. This is a comprehensive standard, encompassing other standards on quality of timber, glazing etc. and those specifying timber windows, which are third party certified to this standard, will meet all current UK requirements.

Specifiers may also wish to include certain levels of safety and security in their window specification. While most modern timber windows offer a good basic level of security, third party certification to Secured by Design standard ensures a enhanced levels. Interestingly, most of the windows my company imports, from a wide variety of Scandinavian suppliers, already meet Secured by Design standards.

We have nonetheless decided to put our popular top swing tilt and turn window through the Secured by Design process for marketing purposes, as this certification is increasingly being demanded by customers.

Another important aspect of specification is ensuring that timber windows meet current thermal requirements. Timber is, of course, a natural insulator, which when combined with the glazing system, (air, argon or krypton filled), insulating glass and draught sealing, has no difficulty in providing a window which meets current requirements of a U value of less than or equal to 2.0W/m2K.

Part L also refers to window energy ratings which follow an A-G scale with E being equivalent to the 2.0 U value. In fact, these standards are not particularly demanding and the technology exists to create a timber window three times as energy efficient!

One final reason for choosing timber for your windows. Planning controls often restrict the use of PVC windows in conservation areas and in buildings of historical interest for aesthetic reasons. This is because PVC windows require a bigger section than timber windows to meet strength requirements and therefore often cannot match the fine detailing of traditional windows, in the way that modern timber replacements can.

More information: www.broxwood.com