Construction Technology III: MMC: Materials and Building Types Study Notes

Led by Dr. Dat Doan at AUT (Auckland University of Technology).
Focuses on materials and building types with a particular emphasis on prefabricated and engineered timber systems.

MMC: Modern Method of Construction.
Prefabrication: A process of assembling components of a structure in a factory to be installed on-site subsequently.
Offsite Construction: Functioning in a location away from the main construction site, typically utilizing prefabricated elements.
Off-Site Manufacture (OSM): A synonym for offsite construction, emphasizing the manufacturing aspect of prefabrication.
Pre-built Construction / Modular Construction: Terms often used interchangeably to refer to buildings that are produced off-site.
Manufactured Building: A building that has significant components built off-site, generally more cost and time-efficient.
Other related terms include industrialized construction, pre-assembly, systems building, and mass production.

Timber is often the first material used for prefabrication and has been common in the residential sector since the 1960s.

Strength
- Timber exhibits a strength-to-weight ratio approximately 20% higher than steel and significantly stronger than non-reinforced concrete (4-5 times).
- Engineered timber, such as Hyne glue laminated (glulam) beams, meets Australian standards and performs predictably under stress.
- Timber burns slowly in a fire without significant deformation, offering better fire resistance compared to steel and better earthquake resilience.
Durability
- With proper maintenance, timber can last hundreds of years.
- Timber does not corrode like steel in aquatic or high-salt environments.
Aesthetic Appeal
- Available in various grades and species, making it suitable for diverse applications.
- Timber gives a warm, inviting atmosphere, lowering stress and enhancing productivity.
Workability
- Being relatively light aids in reducing earthworks and improves site safety.
Sustainability
- Substituting timber can save 0.75 to 1 tonne of CO₂ per cubic meter compared to concrete or bricks, contributing to lower carbon footprints in construction.
- Timber is considered renewable, recyclable, non-toxic, biodegradable, and contributes positively to carbon offsets.
- Utilization of timber aids in maximizing Green Star energy ratings.
Insulation Properties
- Timber is a natural insulator, outperforming masonry, steel, and aluminum.
- It has an insulating capacity 15 times better than masonry, 400 times better than steel, and 1,770 times better than aluminum.

Pest Vulnerability: Timber can be susceptible to termites, woodworms, and carpenter ants.
Environmental Vulnerability: Timber is prone to damage from sun, fire, and water.
Moisture Problems: Absorption leads to potential shrinking and swelling.
Maintenance Costs: Higher than many other materials.
Thermal Performance: Timber has lower thermal mass.
Sound Transmission: Requires careful detailing to avoid sound issues.

Engineered timber is derived from processed raw logs, reconstituted with adhesives for enhanced characteristics. It promotes height in construction due to its stability.

Cross-Laminated Timber (CLT): Layers of solid-sawn lumber glued together with perpendicular grain orientation. This technique provides flexibility, thermal performance, cost-efficiency, sustainability, rapid installation, fire protection, and acoustic performance.
Glue-Laminated Timber (Glulam): Similar to CLT, but oriented in the same direction, mimicking the attributes of a single solid wood beam.
Finger-Jointed Timber: Method involving small pieces of high-quality wood joined together; offers strength advantages but has aesthetic limitations.

Laminated Veneer Lumber (LVL): Provides uniform structural properties and is made from thin veneers.
Plywood: Created by gluing layers of veneer with adjacent grain oriented perpendicular; offers good strength but can suffer from durability issues if exposed to moisture.
Other engineered options: Include Particle Board, Oriented Strand Board (OSB), and Medium Density Fibreboard (MDF).

Closed Light Timber Frame (LTF) Panels: Composed of traditionally framed wall panels, fastening methods allows flexibility in design and insulation standards.
- Advantages: Rapid construction, ease of compliance with NZS3604, and lightweight.
- Disadvantages: Limited prefabrication levels, low thermal mass, and needs detailed engineering compatibility.
Solid Timber Systems: Utilizing CLT panels for walls, floors, and roofs offers speed, precision, and sustainability benefits while retaining higher thermal mass compared to conventional systems.
3D Volumes and Pods: Modular construction method that allows high degrees of prefabrication, suitable for mass customization.

Highlighting successful projects employing timber solutions, including residential, educational, and civic buildings that illustrate efficiency via prefabrication methods.
Notable Examples: 19 two-bedroom houses built in 17 weeks; University of Canterbury student accommodation utilizing assorted timber wall and floor panels; innovative Carterton Events Centre which integrates heritage with modern engineering using LVL for earthquake resilience.

The course encompasses a comprehensive overview of timber in construction, presenting advantages, disadvantages, engineered variants, prefabrication methods, and case studies that demonstrate the versatility and sustainability of timber as a primary material in modern construction practices.

Betz, J. (2019). NZ wood design guides: Designing for prefabrication. NZ Wood.
Hyne Timber. (2017). The benefits of building with timber. Hyne Timber. Retrieved March 02, 2019.
Lawson, M., Ogden, R., & Goodier, C. (2014). Design in modular construction. CRC Press.
Prefab. (2019). How to prefab: A series of New Zealand offsite construction case studies. Prefab.
Smith, R. E., & Quale, J. D. (Eds.). (2017). Offsite architecture: Constructing the future. Taylor & Francis.
Woodworks. (2012). Solid advantages: Cross laminated timber (CLT) offers a new building system option for non-residential and multi-family construction. WoodWorks.