How we do it: Timber
Timber
The Timber Frame Company uses sustainably sourced timber and timber products for all our work. We support the Forestry Stewardship Council (FSC) and Programme for the Endorsement of Forest Certification (PEFC) schemes by purchasing accredited oak, larch and Douglas fir from local sustainable sources whenever possible. The engineered timber products that we source from Scandinavian and European Union manufacturers also meet these criteria, the reclaimed timber we source meets FSC standards by their nature of being 100% post-consumer material. Following dimensional and structural approval from the parties involved and following initial payment, the timber will be ordered and prepared for the carpentry phase or site installation.
Timber Grading
We have a qualified structural timber grader in-house to verify that our products and the timber from our suppliers meets the correct British and EU standards. We can issue Declaration of Performance certificates should they be required.
Fresh Sawn Timber
Our post and beam materials – green oak and Douglas fir for example – are sawn to order rather than from stock sizes from our UK based sawmills. Lead times will vary depending on the processes involved. Green oak is simply sawn to order, curved timber bends for crucks and braces and air dried oak may be chosen from stock logs and boards at the mill prior to being re-sawn for specific purposes. When specifying Douglas Fir we have developed a technique of ‘flash drying’ the post and beam timbers. This process does not reduce the large section timber’s moisture content to usual kiln dried levels, but it stabilises the moisture levels between the sap and heartwood significantly reducing the likely hood of aggressive shrinkage once the building is in use, and mitigates any mould growth on the sapwood margins.
Dried Timber
We specify the most appropriate timber moisture content for its use in the building or structure. We often use air dried oak for example, where the section size allows and where minimal shrinkage is important. We have used kiln dried oak and laminated it to form the structural timber elements, however this is a very expensive and intense process that lends itself to more contemporary construction techniques.
Reclaimed Timber
We have been developing our skills in the use of reclaimed tropical hardwoods such as Greenheart, Ekki and Opepe. Such timber is used in coastal defences, piling timbers in piers and harbours, railway bridges and sidings for example. As an island nation, marine timber renewals are constant so the reclaimed supply of Greenheart is pretty reliable. We have strong links with our supply partners Ashwell Timber and Howard Gibbons Reclamation who have been central to our success. We operate our own small scale sawmill that allows us to re-saw large baulks of these reclaimed timbers cost effectively. There are limitations and risks to reclaiming these materials which can be relatively expensive, however the rewards are worthwhile from an ecological and structural efficiency point of view due to their long service life, incredible strength and durability. We have used these materials predominantly for exterior structures, near water, and even in the ground. The trees these timbers came from are given a third productive life, and in a small way by reusing this national resource we help to reduce the number of tropical timbers from being felled.
Engineered Timber Products
The TFCo have been building an increasing number of more contemporary timber buildings over the last decade or so that incorporate traditional post and beam frames with engineered timber products such as GLuLam Beams, CLT (Cross- Laminated Timber) solid timber panels and sheathed structural enclosure panels in composite elements such as LVL (Laminated Veneer Lumber), I-studs and joists, some of which have won prestigious awards. We have a number of case studies in our portfolio that exemplify these kinds of hybrids where TFCo have provided clients with timber based superstructures that are built and insulated entirely of wood and wood derived products. TFCo have frequently delivered the superstructure from slab to structural shell.
Timber Shrinkage
Fresh sawn timber that has not been either air or then kiln dried will shrink considerably. Externally, air dried timber copes with the fluctuations in relative humidity best and we recommend it is used for cover boards in the direct glazing system, or decking for example. The extent of shrinking per timber depends on a number of factors, particularly the section size, timber species, the position from the log it was converted from, length of time since felling or having been worked and particularly how quickly the timber is enclosed within a heated space from green. We have developed a number of techniques used in the enclosure of large section timber frames that will mitigate the effects that particularly an oak frame will have on its surrounding finishes, for example. We are happy to share these details with our clients, design team and builders.
