Until relatively recently the material choices for multiresidential buildings were limited to the conventional, but the increasing availability of new prefabricated building systems, including mass timber options, and a growing body of knowledge about their use, are changing the landscape.
“Until relatively recently the material choices for multiresidential buildings were limited to the conventional, but the increasing availability of new prefabricated building systems, including mass timber options, and a growing body of knowledge about their use, are changing the landscape.” WoodSolutions.
This is particularly evident in urban infill projects, where site requirements such as long ‘blind’ sides and access restrictions are driving developers and architects to rethink their approach to material specification.
Melbourne architect Peter Tsitas of Peter Tsitas and Associates, cites a project with a long list of challenges.
“Basically, it’s an existing three-storey commercial structure in a Melbourne laneway, and we’re looking at adding more levels, potentially up to 12, that will include an additional mezzanine and two floors for hospitality use and the remaining floors of city style apartments.”
Challenges include physical access constraints owing to the size of the site and adjacent buildings, and the impact of closing the laneway on the businesses and people using the area. In addition, Peter wished to retain much of the existing building, to preserve Melbourne’s historic laneway aesthetic. The proposed solution is light in construction and colour so that it seemingly floats above the existing structure, while the laneway facade is tapered to maintain the lane’s existing character.
He anticipates that overall costs will be comparable, if not less than conventional alternatives, once the savings from faster construction and reduced reinforcement of the existing buildings, owing to the lighter weight of the timber option, are considered. From a design perspective, he says the proposed structure will complement the existing streetscape.
“The materiality and form of the extension is in stark contrast to the existing red brick facade, this turns the existing building into the feature of the design.
“The materiality and form of the extension is in stark contrast to the existing red brick facade, this turns the existing building into the feature of the design.” Peter Tsitas – Peter Tsitas and Associates.
A contrast in almost every measure – age, style, location and challenges – is a new apartment block, The Murphy, by Armsby Architects in Port Melbourne. John Armsby of Armsby Architects, explains: “The project is a boutique development of just seven apartments overlooking a local sporting reserve within Melbourne’s recently rezoned Fisherman’s Bend Urban Renewal Area. On an unusually small footprint site of eight metres wide by 28 metres long, the project will deliver whole floor plate apartments, each of which enjoy views over the parklands to the nearby city skyline.”
Buyer interest in the seven approximately 200 square metre apartments has already been substantial, as many offer 4+ bedrooms and there are few properties of this size in the local market.
One of the key design considerations was the poor soil condition, typically Coode Island Silt where some developments have been required to pile to depths of 70 metres or more. Added to this was the fact that the project is part of an Owners Corporation and shares facilities including access roads with other OC members, so minimising vehicle disruption was imperative.
John explained the resultant decision-making process: “After looking at a range of options, we decided that a lightweight structural solution was appropriate to reduce ground loadings and increase the build speed and minimise disruption during the construction process. We then investigated offsite options, both full modular prefabrication and partial offsite fabrication, and found a modular massive timber LVL solution to be partially fabricated offsite, was the best fit with our requirements.
“After looking at a range of options, we decided that a lightweight structural solution was appropriate to reduce ground loadings and increase the build speed and minimise disruption during the construction process.” John Armsby – Armsby Architects.
The Murphy – a lightweight structural solution was used to reduce ground loadings and increase build speed.
“The physical size and shape of the floorplates, coupled with very little floorplate depth (owing to the need to facilitate nine floor levels within 25 metres of ground level to avoid additional firefighting measures) ended up making full offsite modular construction tricky, while partial offsite fabrication will still realise the benefits of the construction methodology.”
Reduced waste generation, increased speed of erection, less noise on site, minimised cranage time and lowering the potential for damage to existing roadways from concrete trucking all contributed to the decision to go for prefab.
Both Peter and John worked with the WoodSolutions Mid-rise Advisory Team whose pilot program provides free consultancy services in Melbourne and Brisbane. More information about the team and on designing and building with timber systems, is available at WoodSolutions.com.au. ■