AD

Commercial Framing Systems

Thermally Broken Framing Systems

Architectural Windows and Doors

According to Ritchie, this boom in the use of engineered wood products (EWPs) in commercial projects has been driven by two key factors – increased interest in sustainable outcomes and the updating of building codes around the world to consider and allow mid to high rise timber systems as a standard construction method.

“Interestingly we’re just starting to see EWPs take off in popularity in mid-high-rise offices, with glue laminated timber (Glulam) and cross laminated timber (CLT) being specified in a few major office projects in Melbourne and Sydney,” says Ritchie.

As he explains, Glulam and CLT along with another type of EWP known as laminated veneer lumber (LVL), can be produced in largeformat columns, beams, and panels. Lighter, easier to connect, more aesthetic, and better for the environment than familiar precast elements, these products can be used for the same purposes as precast concrete – as columns, beams, suspended floors, loadbearing walls, etc.

“The use of these products offers a range of benefits to a project beyond the obvious sustainability outcomes. They typically weigh about 80% less than a reinforced concrete alternative so they are fast to lift and easier to install. They’re very dimensionally stable meaning they don’t require ugly expansion joints,” says Ritchie.

And, beyond their acknowledged capacity to “imbue a really beautiful raw yet comfortable aesthetic to an indoor space”, they don’t conduct heat well, and can therefore help create very thermally stable indoor environments.

CLT INSTALLED ALONGSIDE STEEL & CONCRETE

According to Kieran Hayes, Senior Technical Engineer at XLAM, CLT is being installed also alongside steel and concrete in a hybrid building typology for buildings of all sizes.

“We are now often seeing CLT paired with alternative beam elements from the traditional combination Glulam,” said Hayes.

XLAM recently introduced the first ever CLT band beam solution.

CLT band beams follow the same principle of manufacture as CLT panels. Layers of radiata pine boards are stacked together in alternating directions and bonded by adhesive. However, these beams are manufactured up to 360mm deep and typically range from 900mm to 1700mm wide.

“These band beams are used in place of primary Glulam, steel or concrete and can be paired with CLT slabs that run over the top.

The CLT slabs can be connected to the beams using inclined screws or adhesive to develop composite action,” says Hayes.

The product was developed in response to two main drivers. The first relates to the fact that, traditionally in Australia, construction of mid-rise buildings has involved the use of PT concrete band beams. These systems have shallow structural depths which allow services to reticulate beneath beams and means there is very little need for coordination between engineering disciplines.

“The CLT band beam system mimics this strategy of service reticulation and takes some burden off inter disciplinary coordination, which can often be a friction point for practitioners engaging in their first mass timber project,” says Hayes.

The second motivation behind the development of the CLT band beam was that previously, before its development, Australia had limited manufacturing capacity for wide and deep glulam beams.

“This was particularly highlighted during the Covid-19 pandemic when there were significant wait times for Glulam elements,” says Hayes, adding that XLAM’s new product represents an alternative option which can be readily produced locally.

When asked about projects that feature the CLT band beam, Hayes pointed to the Maryborough Fire Station, Australia’s first such building to include CLT. An upgrade to the existing art deco brick structure, the project was completed by Hutchinson Builders in association with partners Baber Architects, Bligh Tanner & The University of Queensland.

The design of the new buildings, which include extensive use of exposed CLT and Glulam, was completed with the assistance of 3D building information modelling. According to Hutchinson, this facilitated the off-site design and prefabrication of the individual panels.

Thermal Efficiency

Architectural Window Systems (AWS), a supply of aluminium window and door systems, takes a different approach to sustainability.

The company’s Series 168 Curtain Wall – as used to great effect at Mutual Bank in Maitland, at 102 Wakefield Street in Adelaide, at the Melbourne Hotel in Perth, and elsewhere – is designed to help maximise the thermal efficiency of buildings, and in so doing, to minimise energy requirements.

Developed to meet ongoing changes to building regulations and in particular Section J of the National Construction Code (NCC), the Curtain Wall is available in three types – Thermally shielded, Thermally shielded with clip on aluminium glazing fins, and Thermally broken.

Designed and manufactured in Australia, the systems achieve impressive thermal transmission performance (Uw values range from 1.7-2.5, and SHGC values range from 0.22-0.33).

Included to protect the thermal break from UV degradation caused by the aggressive Australian sun, the anodised aluminium cap is also an ideal adhesion surface for the silicone weather seal between glass and frame and provides protection from potential hail damage. Meanwhile, the sun fin bracket is thermally isolated from the mullion, while the mullion members are extruded in T6 alloy for added strength.

Series 168 Curtain Walls accept double glazing up to 32mm thick. Having been tested for compliance with relevant Australian Standards, they have achieved a water resistance figure of 1124Pa.

Mutual Bank’s new Head Office in Maitland, a building completed by North Construction and Building, illustrates the effectiveness of Series 168 Curtain Walls. The project brief called for a striking, modern design that also delivered in terms of energy efficiency.

The design delivered by the architects dwp delivers on both these terms. Featuring expressed mullions, horizontal sunshades, a 105-degree faceted corner and bracketry detail, the building also includes window, door, and curtain wall solutions from AWS’ Elevate Aluminium range.

Specified by Superior Windows, Series 168 Curtain Wall was a key inclusion. Apart from ensuring a Uw Value as low as 1.7 and helping meet thermal efficiency goals, it delivered the flexibility required to facilitate the inclusion of a custom faceted corner and bracketing detail on the structure’s primary facade.