Why Timber Frame

Large areas of medieval England were covered with forests, so it is not surprising that until 400 years ago timber was the principal building material in Britain. Even in the Cotswolds and Derbyshire, where other materials such as stone were readily available, timber was preferred, for it was plentiful, cheap and easy to handle, with the added advantage that every woodland cleared provided additional land for cultivation.

The timber-framed buildings that survive today do not reflect the almost universal use of timber until about 1500. Although timber was the principal building material, it was not until the latter part of the 16th century that oak was used almost universally, for until that time ‘men were content to dwell in houses built of sallow, willow, plum tree, headbeam and elm’.

With oak being restricted to the construction of churches and other religious establishments, and to princes’ palaces, noblemen’s lodgings and ships, between 1550 and 1660 buildings of inferior timber were often rebuilt in oak, or in stone in those areas where it was available.

In Saxon times, most buildings were of timber. These timber-framed buildings can be classified into two types: box frame and cruck construction. Box frame construction was by far the most common and comprised horizontal and vertical timber members jointed together to form a wall with the open panels infilled or with the entire wall covered with an appropriate cladding material.

In cruck construction, pairs of inclined cruck blades were spaced at intervals along the building to collect the roof loads by means of ridge-beams, purlins and wallplates to transmit the loads to the ground. The walls, which were non-structural, were often timber-framed but could be of any material. Within both groups were many variants; in box frame there was the close studding, post-and-truss and interrupted sill, while in cruck construction there were, apart from the crucks, many forms, the most important being the base-cruck and jointed cruck.

The structural use of timber was, therefore, in use for centuries, with surviving examples spanning for some six centuries. During this long period, timber-framed buildings were affected not only by the various technical developments which occurred, by also by the many local traditions which influenced the appearance of these buildings from region to region.

During the 18th century, British forests were so depleted that it became increasingly necessary to import softwood from northern Europe and Scandinavia, supplemented in the 19th century with supplies from Canada and the United Sates where timber-framed homes are now almost universal. These softwoods, particularly with modern preservatives, are vastly superior to the timbers used in earlier times.

Ever conscious of the need to preserve and enhance the environment in which we live, we at SupaHome by Maple continue to develop our buildings, applying new technologies and ensuring continuity for the future.

In the third millennium, timber-frame construction uses timber as the skeleton of the structure. This can take many forms, including the cruck frame and post/beams methods of old, to the more modern engineered timber products such as laminated beams and fibrous boards.

At Maple, the bulk of our business revolves around platform frame construction, using a series of timber studs and rails to form prefabricated wall panels in storey heights on which is supported the floor structure, again using timber joists and engineered board flooring, to form the first platform on which subsequent levels are built up to the roof structure. The frame can be clad with any of the usual, and many unusual, materials; indeed it is often the case that the structure type of the house cannot be determined without detailed investigation.

When compared to other building methods in use today, timber-frame has many benefits. The major benefits to the self-builder include, but are by no means limited to, the following:

Speed of Erection: A dry, weatherproof shell can be achieved in a fraction of the time taken for masonry construction, resulting in a reduction in capital outlay and enabling internal work to proceed without regard to weather conditions.

Building Regulations: All of Maple packages exceed the requirements of Approved Document L1A. Our current specification outlines the standards of insulation offered, including the extra insulation levels offered by the Eco-pack and SupaWall(r) options. Please note that our standard specification is a starting point – we can tailor every package to include as much or as little as you require, and we can alter the specification of individual components to meet your needs.

Approved Document L1A: Conservation of fuel and power in new dwellings. There is now only one approach to demonstrating compliance with the energy efficiency requirements. This addresses five key criteria:

• The annual C02 emission rate of the completed dwelling, as calculated using SAP 2005, must not exceed the target set by reference to a notional building
• Building fabric and services performance specifications are within reasonable limits
• Solar shading and other measures to limit risks of summer overheating are reasonable
• Fabric insulation and air tightness, as built, are as intended
• Satisfactory information must be provided enabling occupiers to achieve energy efficiency in use. (Information to be provided in the forthcoming Home Information Packs).

The technical provisions mean that higher standards of fabric, heating, ventilation and lighting systems designs will be necessary, delivering an overall improvement of 20% on average.

Quality control. As the bulk of the construction process is carried out under factory conditions, including assembly of external panels and internal partitions, trimming to length of joists and rafters, etc, there are fewer margins for error. The site is treated as point of assembly for the prefabricated structure, not where manufacturing is carried out.

Fully engineered. Structural engineers design each individual building. They have particular experience in timber frame systems and a certificate is provided on completion to indemnify the structure. All components are stress graded, engineered, British Board of Agreement (BBA) certified or comply with current British standards, and a rigorous checklist is completed with the client or their representative when erection of the building has been completed on-site.

Sound insulation. It is a common misconception that timber-frame structures transmit sound more readily than masonry constructions. Field-testing by the Building Research Establishment (BRE) has shown that timber compartment walls have a success rate of over 99% in meeting sound insulation regulations. Masonry walls achieve only 50-70% pass rate, mainly due to the quality of workmanship on site, such as mortar joints not being fully filled (even small gaps can result in seriously reduced performance). It is with this in mind that, as standard, we insulate all internal partitions for acoustic purposes.

These factors, along with other benefits including flexibility of design, combined with the fact that the vast proportion of the world’s houses are timber-frame structures, should go a long way to convince you that there is only one option available when building your own home.