Melbourne’s sustainable development requires urban infill, especially less intrusive mid-rise buildings and vertical extensions, which often provide the best value: location, floorplans, views, acoustic and thermal efficiency… but also a quick delivery and an easier customization can make a difference.
Considering the new Better Apartment Design Standards, how is it possible to get “more from less” in this boosting yet highly competitive market?
Timber structures are the answer: an increasing body of experiences, in Australia and abroad, demonstrates the advantages that building with Engineered Wood Products provide to both developers and clients.
On the “MORE” side of the equation, the most relevant feature is speed, through improved safety during construction and easier off-site prefabrication of components. The building process is much faster than with concrete and crews work quicker on site because they feel safer, assembling lighter components with tighter tolerances, simple connection technologies and small tools.
An outstanding example is the ten storey residential development at Banyan Wharf, London from Hawkins\Brown architects comprising 50 apartments - all sold off plan, together with 1,190 square metres of commercial units.
Complete use of CLT was not a necessity for the structure and using stud partitioning for some internal walls has permitted future owners the option of reconfiguring their apartments in due course, if required.
The main benefit of timber construction was cost and programme certainty: a reduction in lifting works which helped with site restrictions, start of follow on trades work on the lower floors whilst the structure for the upper storeys was in construction, and most importantly just in time deliveries, as there was only room for a single trailer or van.
In the National Construction Code, timber structures are considered very safe for fire risks because, additionally to the first line of defence (sprinklers, encapsulation, non-combustible insulation and cavity barriers), they provide a highly predictable behaviour and additional safety from slow charring, thus allowing to reduce the wall thicknesses and maximise the living space. See specific technical information here.
The durability specifications attribute the higher risk to the corrosion of steel components, rather than to wood borers or rot, when design and execution are correct. Perry House, a timber structure with masonry façade built in 1913 in Brisbane and currently used as an hotel, proves that wood can be very durable even in a semi-tropical climate.
Information from both historical performance records, extensive laboratory research, and field experience was used to develop a probabilistic durability design method, described in WoodSolution’s guide to assists specifiers in the selection of products and designs with respect to service life requirements.
Moreover, as timber structures are very ductile, achieving full safety with respect to high wind and earthquake events is easier and more cost-effective than with brittle concrete-based products.
Considering now the “LESS” side of the equation, a factor with paramount importance for developers and builders is the significant reduction of preliminaries (foundations, cranes, scaffolding, stock of materials…) and of follow-up trades (plumbing, electrical, finishes…), both in terms of costs and times. With the same quality, or better.
As an example, the 10-storey, 121-unit development at Dalston Lane in London, weighing a fifth of a concrete building of its size, allowed reducing the whole construction costs by 15 percent, mostly from smaller foundations, and the addition of two stories of accommodation (15 apartments), with respect to the reinforced concrete option.
Also, the number of truck deliveries during site works was 80 per cent lower, resulting in minimum disturbance to the neighbourhood. The architect, Andrew Waugh, reported his experiences on this and other timber buildings he designed within our seminar, along with architect Jonathan Evans from Tzannes, who discussed the benefits of using timber for the 7-storey International House Sydney.
A design based on Engineered Wood Products, both framed and/or massive, provides a more efficient and less costly solution for mid-rise residential construction: in a number of mid-rise projects we are currently advising for, the cost benefit ranges from 4-15% and the program shortening is typically 4-6 months. With tighter tolerances and easy, accurate assembly which can be managed by ordinarily-skilled crews. In other terms: more performances and less variations.
Last but not least, a report from Planet Ark shows that “more from less” means also achieving all the environmental advantages of a sustainable, certified and fully renewable resource with unique beneficial effects on occupant’s health and indoor air quality.
WoodSolutions’ free advisory program is providing inspiration, evidence of suitability and design resources to interested building professionals, with no reference to product brands and the only aim to disseminate technical information applicable to mid-rise projects.
Last but not least, the Victorian supply chain is efficient and ready to support the forecasted growth.
More from less? Yes, it’s happening.
Wood Solutions is continuing with its seminar series with the latest to be held on Wednesday March 8th titled 'Discover new directions in mid-rise timber construction'; to attend, make your booking here.