Health Building Carbon Footprint Model
This section provides information on the health building used in the NZ Wood carbon footprint model.
Many modern buildings tend to make extensive use of timber, steel, and concrete materials in construction, all of which can be energy-intensive to produce, via processes that have the potential to cause adverse environmental impacts and give rise to CO2 emissions.
However, recent developments in wood technology and engineered timber products, seismic and acoustic design, fabrication and construction techniques have enabled timber to be utilised much more extensively for instance in the basic structure of medium-rise, multi-storey buildings, such as a typical ‘down-town’ office block.
While there is a tendency for buildings to be labelled according to the main material used for their sub-structure and super-structure, the vast majority of buildings use a large number of different materials, from a variety of sources, both national and international. From a materials perspective, a building becomes a very complex system and it is often not immediately clear which materials or combinations of materials provide the best environmental performance.
Studies have indicated that when considering the environmental impacts of building materials, the structural components used in a building are of significant importance.
The building designs covered by the NZ Wood carbon footprint model emphasis alternative structural design options where the predominant structural material is either timber, steel or concrete.
Description of Health Building
The Health Centre (1,640 m2) is typical of the types of buildings being funded by the NZ Government. The as-built design – detailed below – was modified and re-designed to provide the alternative designs.
Cost and environmental impact analysis (June 2006) by Ian Page.
BRANZ report E408 Timber in Government buildings - PDF
Summary of as Built Design
A suspended concrete floor on a gently sloping site with steel and concrete columns and steel roof framing.
The wall cladding is a mix of fibre cement sheet and sheet steel.
In all designs, an attractive architectural appearance was retained rather than redesigning for the cheapest cost material.
The same exterior form and cladding was used for the steel and timber designs; however, the concrete columns were replaced with smaller timber and steel columns and covered with the cladding.
The interior consists mainly of consulting rooms and waiting areas.
Summary of re-built design
- Steel design – Largely as-built above with light steel framing for exterior and interior walls. Concrete columns were replaced with steel UCs and the original concrete floor was replaced with steel tray and concrete topping on a steel UB supporting system.
- Timber design – LVL posts used instead of the original steel columns. Roof in LVL or nail-plate trusses and the floor as particleboard or Hybeam joists on LVL bearers and a plywood floor. Roof purlins solid 250 x 50 timber purlins. Bearer supports in H3.2 timber posts on concrete pads.
- Concrete design – Exterior cladding and foundations replaced with tilt slab panels. The original steel columns, floor and foundation system were retained. Roof structure as for the steel design.
View Health building comparison data - Excel document
