Timber framing
Timber framing is a system of construction in which large wooden posts and beams are used to create the structure of a building. Timber framed buildings may also be known as half-timbered where they are constructed using a particular technique which leaves the wooden structure visible on the exterior of the finished building.
The structure
The main structure of a timber framed building is a frame of large wooden members joined together using mortice and tenon or other joints fastened with wooden pegs. Different styles of timber framing use different structural systems and describe the members using different terminology.
The vertical timbers include posts (main supports at corners and other major uprights), and studs (subsidiary upright limbs in framed walls).
The horizontals include sill beam, (also called ground-sills or sole-pieces, at the bottom of a wall into which posts and studs are fitted using tenons), noggin-pieces (the horizontal timbers forming the tops and bottoms of the frames of infill-panels), and wall-plates (at the top of timber-framed walls that support the trusses and joists of the roof).
The sloping timbers include the trusses (the slanting timbers forming the triangular framework at gables and roof), braces (slanting beams giving extra support between horizontal or vertical members of the timber frame), or herringbone bracing (a decorative and supporting style of frame, usually at 45 ° to the upright and horizontal directions of the frame).
Timber frame buildings can be enclosed in a variety of ways. These include filling the spaces between timbers with panels of wooden planking, plaster, wattle and daub, or brickwork (sometimes known as noggin). This method of infilling the gaps creates the half-timbered style, where the timbers of the frame are visible both inside and outside the building. Recently it has become common to entirely surround the timber structure in manufactured panels, such as Sips (Structural Insulating Panels). This method of enclosure means that the timbers can only be seen from inside the building, but has the benefits of being less complex to build and offering more efficient heat insulation.
Distinctive features of timber frame structures
Timber framed structures differ from conventional wood framed buildings in several ways. Timber framing uses fewer, larger wooden members, commonly using timbers with dimensions in the range of 6" to 12" as opposed to common wood framing which uses many more timbers with their dimensions usually in the 2" to 10" range. The methods of fastening the frame members also differ, in conventional framing the members are joined using nails or other mechanical fasteners while timber framing uses mortice and tenon or more complex joints which are usually fastened using only wooden pegs.
History and traditions
The techniques used in timber framing date back thousands of years, and have been used in many parts of the world during various periods such as ancient Japan, Europe and medieval England.
In England the Wealden house, in the Weald of Kent and Sussex, was one such type of timber-framed structure. The structure consisted of an open hall with bays on either side and often jettied upper floors. However, it was mainly in Tudor country houses and cottages that timber framing is found, as well as in the several types of Tudor or Elizabethan Revival styles of the late Nineteenth and early Twentieth century.
However, in later revival styles the load-bearing timber frame structure was often replaced by walls of brickwork or other materials, to which a decorative pattern resembling timber framing was added on the outside of the walls.
In Germany, too, the Deutsche Fachwerk Straße, the “Route that links Germany’s Medieval Timber-framed Houses”, that runs from Lower Saxony in the north of the country, via Hesse and southern Thuringia to Bavaria is an area renowned for its highly picturesque half-timbered buildings.
The ancient craft of timber framing has had a resurgence since the 1970s. This is largely due to such practitioners as Jack Sobon and Ted Benson who studied old plans and techniques and revived the technique that had been long neglected.
The assets of timber framing
The use of timber framing in buildings offers various benefits including aesthetic ones and also structurally, as the timber frame lends itself to open plan designs and allows for complete enclosure in effective insulation for energy efficiency.