Communing with timber

Architectural vision of communal buildings often presents a challenge at construction stage

Published: 04/08/2010 00:00

The design of communal buildings requires thought as to how the internal space will ultimately be used. For most a large, open space that is uninterrupted by posts or columns is the ideal scenario, making the space flexible and suitable for a number of sporting or community activities. Here Kevin Riley, Vice President Construction Industry for Finnforest UK explains why timber is becoming more popular as a material specification choice for these applications.

 


Kevin Riley

Often an architectural vision presents a challenge at construction stage, with the application of value engineering and some compromise involved in achieving the architect’s vision. For communal buildings there is often a key requirement: the creation of one large homogenous space that is uninterrupted by posts, beams or columns - space that can be used for school assembly rooms, sporting facilities such as gymnasiums and swimming pools.

The construction of large buildings with an internal void is a challenge, yet the latest timber engineering technologies are rising to that challenge, becoming more widely specified for a number of applications where other materials just can’t deliver the same performance requirements.

A portfolio of engineered timber has been specifically developed to help building engineers achieve the dynamic structural designs that architects envision. Combining a high strength to weight ratio with high rigidity means that the precision tolerances of large spans and even geometric renderings like vaulted roofs can be achieved.

Through advanced processing techniques, timber is engineered to create products such as Kerto, exclusive to Finnforest, Glulam and Structural Plywood.  Engineered timber products eradicate the natural defects such as knots and resin pockets that occur in wood by dividing and randomly distributing them throughout the final product. In this way engineered timber differs from a homogenous piece of sawn timber, where the natural weakness would be present in the same position throughout the product.

A great example of this in action can be seen where Constructional Timber Ltd has recently used seven 32m long glulam beams to construct the roof of the swimming pool at Botwell Green Leisure Centre within the London Borough of Hillingdon, designed by Burke Rickhards Architects. The new leisure centre replaces the old outdated leisure facilities nearby and has been designed to allow for a greater capacity of visitors from the local community.

Due to the sheer scale of the structure a building material that would be able to meet the structural demands of the building without compromising on the interior space was required. GL32 Glulam was selected on the basis of its inherent strength and the availability of lengths to meet the wide span demands of the building’s size.

Weighing 4.5 tonnes the Glulam beams were delivered to site in two instalments and were lifted into place with an industrial crane.

The structural capabilities of the Glulam enabled the achievement of very precise tolerances. Meanwhile the moisture levels of the interior environment a swimming pool would create were also a key consideration. Under such circumstances steel was simply not an option. Glulam on the other hand can be installed straight away with any required coatings having been pre-applied so it can resist the damp and humid conditions present within the space during its use. This was the case with the Botwell Green Leisure Centre, with the Glulam beams having a Sadolin waterborne quick drying wood stain applied at Finnforest’s Hartola Glulam mill. The natural timber appearance provides an additional aesthetic value to the pool’s interior too.

Manufactured from sawn structural timber, up to four lamellas are cut along the grain and glued together to produce beams and panels. This manufacturing process makes Glulam extremely strong and means it is possible to produce beams up to 32 metres in length to create wide, uninterrupted spans at just two thirds the weight of steel.

Glulam is not the only engineered timber solution for wide, uninterrupted spans, there are versatile options depending on the exact stresses the application demands. For example, Kerto-Ripa is an engineered timber panel solution which can be used to construct a roof deck that spans up to 18m, with fewer interruptions and structural connections. This means that wide communal areas such as a sports hall, swimming pools, library, classroom or retail space can be created with fewer or no supporting pillars, lessening the amount of materials required onsite overall.

Kerto-Ripa is a technologically advanced panel constructed of structurally glued Kerto members, which can be created as an open panel, allowing voids for hiding services and insulation. In fact, Kerto-Ripa can be used in thermo-insulated structures to achieve BREAM Good, Very Good or Excellent, depending on the level of insulation chosen.

Engineered timbers are versatile construction materials. In addition, when properly managed, timber is one of the most sustainable construction materials available. During the specification, planning and procurement processes, timber that is certified - with a credible and fully audited chain of custody - will carry the reassurance that it has been legally sourced and processed. This is the case with all products, systems and solutions from Finnforest that carry the PEFC label

There is an engineered timber solution to meet the demands of almost any application. Now with the emergence of new and ever more exacting technologies, timber is set as the frontrunner for wide span communal buildings where space, precision tolerances, aesthetics and environmental performance dictate the material specification.