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About the Project
The holiday and sailing resort of Dartmouth in Devon was chosen by Sainsbury’s as their first new site to trial ‘green building’ in earnest across all aspects of the store’s design and operation. In locations like this, the regular custom from locals is significantly supplemented by holidaymakers during the summer, who appreciate a more relaxed shopping environment. Because the store is set into a hill it was decided to create a dominant curved roof feature to reflect the immediate topography.
The store comprises 18,500 ft2 of selling space at the front of the building, 6,500ft2 of storage space at the back on ground level and a similar floor area above on a mezzanine level which accommodates an office and heavy plant equipment.
The front of the store is structurally supported with laminated Spruce columns, shaped rafters and purlins. The exception being the external columns at the very front of the store, which are in Larch – chosen for its greater durability (rated moderately durable) that removes the need for preservative treatment. The back of the store is very similar but uses steel columns instead of timber. The roof is braced with tubular steel members. Cladding to the building comprises insulated composite wall panels with either timber shiplap boards or lime render.
The Benefits for Retail
Using glued laminated timber (glulam) as the primary structural material is attractive to large retailers for a number of reasons. Firstly, it’s useful to have a viable alternative should steel become unaffordable in the future, a key material in previous stores. The price of structural steel components has risen by as much as 50% in the last 2 years, mainly due to the rising cost of energy, whilst the corresponding increases in timber have been much less.
Furthermore, retails’ vast range of customers greatly appreciate the positive contribution that visible timber construction elements make in terms of the atmosphere and environment. Timber has a vastly reduced impact on the planet due to its carbon content (the carbon storage effect) and requires far lower energy commitments to produce, process and transport the material.
Safety-wise, timber members char on faces when exposed to fire but still retain strength and stiffness by virtue of the much cooler core within the charred surfaces. Their performance is predictable and collapse is highly unlikely.