Over the past few years, external cladding has become the ubiquitous image of timber in construction.

In some instances, however, it would be fair to say that the decision to employ timber cladding on a building’s exterior has not been backed by the necessary technical knowledge or the requisite construction skills to achieve a successful result. The consequence of this is there for all to see – differential weathering at best, fungal growth and unsightly stains – and sometimes even wet rot – at worst. None of this is welcome news for timber’s long-term reputation as a material suited for exterior use, but so many of the often all-too-apparent problems can be easily prevented if good practice is followed and elementary design and installation mistakes avoided.

In part these problems can be attributed to a lack of knowledge at the design stage about the properties of the various timbers suited for external use; in part to a lack of understanding on the installer’s side about simple issues such as suitable fixings and necessary expansion gaps between boards. None of this is rocket science and indeed there are many in the construction industry who view external timber cladding as nothing more complicated than nailing planks to a wall and who staff the job accordingly. Perhaps, as a consequence of this simplistic attitude, there has until now been very little information available to either group that has been based on long term research and testing of the various issues confronting the timber façade designer and installer: in short the hard empirical evidence on which objective specification guidance and performance-based standard, robust details can be founded.

All that is about to change, however, with the forthcoming publication of Ivor Davies and John Wood’s Designing the Timber Façade – the result of research carried out by Edinburgh Napier University’s Forest Products Research Institute. Originally part of an EU-funded Northern Periphery Programme study into the use of timber cladding in maritime climates, the publication’s contents have been considerably extended from that base to embrace a wealth of additional material dealing with the two primary (and often conflicting) issues faced by designers and specifiers today – moisture and fire.
Divided into six sections the book, begins by explaining what is meant by performance-based design and the issues affecting the use of timber as a façade material. The following eight chapters explore moisture control in detail and cover everything from fungal decay, insect attack, weathering and dimensional change to how to effectively design for durability.

Because of its importance and because so little useful information has hitherto been available on this subject for designers, specifiers and contractors, fire occupies the next large section of the book, with important chapters on the various regulations that prevail in different parts of the UK on the use of timber on building exteriors as well as a valuable focus on provisions to limit external fire spread.

Vertical shiplap cladding in alternating directions on John Hope Gateway, Edinburgh

The final section provides a wealth of performance-based design detail drawings covering all the standard junction difficulties encountered when considering the use of external timber cladding on new buildings.

Designing the Timber Façade offers robust, evidence-based information on how timber cladding performs in external environments. All in all, the bible on the subject that every designer bookshelf must have.

Published by Arcamedia, Designing the Timber Façade will be available from early November. For further
details, contact Peter Wilson at the Wood Studio in Edinburgh Napier University’s Forest Products Research Institute. Email: pr.wilson@napier.ac.uk or tel:0131 455 2272.

Dumfries Dental Centre by Archial Architects

Printer friendly version

Email this article to a friend

Bookmark this

---