Windows 

Wood windows are increasingly recognised as the best-looking, as well as the most sustainable, solution. Manufactured from certified timber and with guaranteed service life and low maintenance requirements, they score better than other window materials in LCA profiling. Over recent years the wood industry has worked with suppliers and manufacturers to produce highly durable finished timber products backed by performance guarantees. Most of today's wood windows come:

• Fully-finished with guaranteed paint/stain systems and low maintainance requirements
• Factory double-glazed - in clear, obscure, laminated, leaded or toughened safety glass - all compliant with BS 6262 1982 and NHBC recommendations
• Fitted with ironmongery meeting high security and insurance requirements
• A minimum compliance to Part L - many wood windows are able to provide energy saving u-values lower than 1w/m²k.

This has resulted in a significant and sustained increase in market share.

Now, for the first time ever, high quality wood window companies have come together to provide the UK market with a range of products and services that can be specified with confidence, through the Wood Window Alliance.

Wood Window Alliance members supply windows which meet a set of quality standards that are independently audited. They must:

• Meet the minimum standards set out in BS 644, the main British Standard for wood windows, or equivalent standards from other countries
• Meet the minimum performance standards for wind and weather resistance of BS 6375 Parts 1
• Meet the minimum performance standards for operational aspects of BS 6375 Parts 2 or equivalent standards from other countries
• Be accredited by an independent UK or European body to prove compliance with those standards
• Be manufactured from certified timber, sourced legally from sustainably managed forests
• Have service life warranties for durability, paint life, ironmongery and insulated glass units
• Meet or better the UK Building Regulations recommendations for energy efficiency

Performance

Backed by new Life Cycle Assessment and service life data, windows bearing the wood quality mark come with low maintenance, and long life guarantees. Wood Window Alliance windows meet or exceed independently audited standards for weather performance. They also demonstrate compliance with sustainable timber requirements.

Energy efficiency and double glazing

Nowadays, a window's thermal efficiency is a key part of reducing any home's overall energy needs, meeting building regulations and complying with the Code for Sustainable Homes.

Because wood is an excellent thermal insulator, wood windows have an inherent advantage. But thermal performance is also governed by the specification of the double (or even triple) glazing, and by the detail design of the windows themselves.

Specifying a Wood Window Alliance window gives you the confidence it will meet British or European standards for weather protection and storm proofing, and for energy efficiency, with thermal ratings to meet, or exceed, current building regulations. Some members may indicate their Window Energy Rating (WER) through BFRC (British Fenestration Ratings Council) or similar rating systems operational in Europe.

Durability

Good quality wood windows are an investment that can last a lifetime. Manufacturers offer extensive service life warranties on windows carrying the mark.

Low maintenance

Modern wood windows are easy to maintain. Fully factory-finished windows carry substantial warranties on the paint or stain finish. Improvements in paint technology mean that re-finishing is a low-cost exercise with a rub down and a single coat of paint, with no need for time consuming sanding down, burning off, or chemical stripping.

Repairability

Unlike other types of window, wood windows can be repaired easily, extending their life (and their carbon store) still further, meaning even less impact on the environment than replacements.

Even higher specifications

These standards are minimum requirements. Wood Window Alliance members often manufacture to even higher standards to meet 21st century demands, whether for SBD (Secured by Design), zero carbon housing or other requirements.

For more information visit www.woodwindowalliance.com

Warranties

The TWA (Timber Window Accreditation) Scheme operated by the British Woodworking Federation is one of the independent auditing bodies recognised by the Wood Window Alliance. It offers a BS Kitemark. TWA Scheme windows holding the kitemark are fully factory finished and ready-glazed. They offer the following warranties:

30 year warranty against rot and fungal attack on all external timber components

10 year warranty against double glazing failure for factory fitted glazed windows

10 year warranty against manufacturing defects

8 year warranty on paint finish

5 year warranty on stain finish

For more information visit www.bwf.org.uk

Treatment

Generally all exterior joinery is pressure treated within the manufacturing process with products such as Vacsol Azure, a solvent based preservative containing biodegradeable fungicides and insecticides or Protim Clearchoice, water based Protim Aqeos or Protim Drysol, with organic preservatives. For more information see www.osmose.co.uk and www.archtp.com

Finishes

Windows can be supplied direct from the factory with a range of finishes. These include base coat stains, offering short term protection before on-site finishes are used as well as full finishes in a variety of stains or paint colours, eliminating site finishing. Fully factory-finished wood windows provide a superior and guaranteed paint or stain application and reduced maintainance requirements.

A wide range of exterior finishes and applications are available, for a comprehensive list of wood care products visit www.sikkens.com / www.sadolin.co.uk or www.archchemicals.com/Fed/WOOD

Learn more from the Deck design and installation module in wood for good’s Online Learning. It’s free to architects, specifiers, members of the TTF and wood for good. To register free click here