Timber Building Systems

1.1 Sawn Timber Products

Sawn timber refers to solid wood milled directly from logs into structural sections. It is widely used for framing, cladding, decking, and joinery. Sawn products can be recomposed into larger members, such as finger-jointed boards or mass timber laminations, removing characterisation like knots.

• Common species in Australia:
  • Softwoods
    • Radiata Pine (Pinus radiata), Slash Pine (Pinus elliotti), Hoop Pine (Araucaria cunninghamii), Cypress Pine (Callitris spp.), and more...
  • Hardwoods
    • Southern Blue Gum / Tasmanian Blue Gum (Eucalyptus Globulus), Shining Gum (Eucalyptus nitens), Spotted Gum (Corymbia spp.), Blackbutt (Eucalyptus pilularis), Messmate / Stringybark group (Eucalyptus obliqua, Eucalyptus maculata, etc.), Jarrah (Eucalyptus marginata), Karri (Eucalyptus diversicolor), and more...
  • Note: “Hardwood” and “Softwood” refer to botanical differences, not material hardness. Hardwoods are broad-leaved angiosperms with enclosed seeds, while softwoods are needle- or scale-leaved gymnosperms with exposed seeds. Balsa is technically a hardwood despite being extremely light, and Douglas fir is a softwood despite being dense and strong. For this reason, some European texts use the terms leaf wood and needle wood instead.
• Strengths:
  • Readily available, cost-effective, easily worked, and versatile
• Considerations:
  • Typically requires grading, and often treatment for durability and termite resistance depending on the application and hazard class.

Machining and Dressing

Sawn timber is commonly machined to produce a specific profile or finish.
Dressing refers to machining that improves surface finish and dimensional accuracy, but does not imply profiling. All dressed timber is machined, but not all machined timber is dressed.

Tip: Pay attention to the moisture content of your sawn timber and the condition of the supply stock. This helps you minimise movement in service and get more reliable performance out of each element.

Figure 1: Sawn timber profiles (WS TDG 46 p71)

Sawn timber products are used as-is, treated, and recomposited into a staggering variety of products including:

• Landscaping or foundations in rounds or dressed sections

• Lightweight timber framing (treated sawn timber)

• Glued-laminated components

• Cross-laminated components

1.2 Veneer Timber Products

Veneer-based timber products are manufactured from thin layers of wood, typically 3–6 mm thick. Veneers are produced by peeling logs in a continuous rotary process, delivering exceptionally high recovery from the raw resource. These veneers are bonded together using adhesives, heat and pressure to form billets or panels that are then sawn or cut into final products. Because the timber is recomposed from thin layers, veneer-based products offer excellent dimensional stability and highly consistent mechanical performance. Most LVL is produced from softwood species, although hardwood LVL is also available. If you’re new to engineered wood, the plywood family is usually the most familiar entry point.

Some veneers are used purely for aesthetics, allowing designers to showcase scarce or high-value decorative species in an efficient way.

Figure 2: Veneers combined into a larger section

Veneer products are used as-is, treated, and recomposited in a staggering variety of products including:

• Visual products such as decorative linings/plywood, and flooring.

• Structural products such as Laminated Veneer Lumber (LVL), structural plywood, and I-Beams.

• Large elements, such as Massive Ply Panels or within other glued elements for extra strength.

1.3 Strand Timber Products

Strand-based products involve a high degree of fibre recomposition. Timber is shredded into controlled strands and re-formed using adhesives, orientation control, heat and pressure. This approach produces highly homogenous products with strong, predictable performance characteristics. Strand products also achieve very high yield from the raw log and make efficient use of a wide range of fibre types, improving overall resource utilisation.

The most common strand product in the Australian market is Oriented Strand Board (OSB). Other products made from long strands in heavy structural components are Parallel Strand Lumber (PSL) and Laminated Strand Lumber (LSL) which can have strands in the same orientation, or varying orientations. Neither of these products are produced within Australia, however there is availability through importers. Innovators are exploring the fabrication of even larger elements such as mass timber stye Cross-Laminated Strand Lumber (CLSL) creating truly huge building products from these small strands.

1.4 Assemblies and MMC (Modern Methods of Construction)

Assemblies bring together sawn, veneer and strand-based components into more complex systems. These may include prefabricated wall, floor and roof cassettes, structural frames, volumetric modules or hybrid mass-timber systems. Assemblies of various kinds bridge between individual timber product types and complete building systems, including:

• Prefabricated light-timber framing

• Mass-timber floor and wall systems

• Multi-material hybrid assemblies

• High-performance façade systems

• Engineered connectors and fasteners forming part of the overall system design

Suppliers across the timber sector engage with Modern Methods of Construction (MMC) in different ways depending on their materials, machinery, logistical capacity and commercial positioning. The MMC Definition Framework categorises modern construction into seven categories. These categories provide a useful lens for understanding why one supplier may choose to produce a simple sub-assembly while another may invest in full volumetric modular delivery. Below is an overview of the seven MMC categories followed by an explanation of the key factors influencing supplier choices.

The Seven MMC Categories

1. Category 1 – Pre-manufactured 3D primary structural systems
   (Volumetric modules, pods, bathroom pods, plant rooms.)

2. Category 2 – Pre-manufactured 2D primary structural systems
   (Panels, CLT, framed wall cassettes, floor cassettes.)

3. Category 3 – Pre-manufactured components, assemblies and sub-assemblies
   (Stair units, roof cassettes, I-joist floor systems, trussed rafters.)

4. Category 4 – Additive manufacturing and 3D printing

5. Category 5 – Non-structural sub-assemblies and components
   (Services risers, façade units.)

6. Category 6 – Traditional building product innovations
   (Improved fixings, digital cutting, novel connectors.)

7. Category 7 – Site process improvements
   (Digital workflows, onsite robotics, improved QA processes.)

Most timber suppliers operate within Categories 2, 3, 5 and 6, with a smaller number engaging in Category 1 due to capital intensity.

Key Takeaways

• Sawn, veneer and strand products differ mainly in fibre recomposition, which determines consistency, strength, dimensional stability and typical applications.

• Sawn timber is versatile, familiar and widely available, but varies with species and defects; used across framing and simple assemblies.

• Veneer products offer high consistency, long spans and excellent stability due to layered construction.

• Strand products  are highly resource-efficient and homogenous, suited to sheathing, bracing and engineered components.

• Assemblies combine these products into systems ranging from trusses and cassettes to panelised mass timber and modular units.

• Supplier choices within the MMC framework are shaped by plant investment, workforce skills, logistics, digital capability, risk appetite and market demand.

• Different product types naturally align with different MMC categories, with most Australian suppliers operating in Categories 2–3 (panelised or sub-assemblies).

Performance characteristics such as moisture resistance, fire safety, and durability are covered in detail elsewhere.

Timber construction is rapidly evolving, bridging traditional techniques with modern engineering innovations. Choosing the right structural system ensures code compliance, cost-effectiveness, and long-term performance in timber buildings.

Timber construction systems range from lightweight framing to large-format mass timber and hybrid assemblies. The choice of structural system depends on building type, height, desired speed of construction, and performance requirements such as fire resistance, acoustic separation, and thermal efficiency.

This section introduces the primary timber systems in use across Australia and provides links to detailed design and compliance guidance.

2.1 Light Timber Frame Construction

Overview
Lightweight timber framing is the dominant construction method for Class 1 residential buildings: housing and terrace housing. Framing typically uses MGP or F-grade softwoods, assembled into walls, floors, and roof trusses.

Features

• Built with repetitive stick-framed elements (studs, joists, rafters)
• Bracing is provided by sheet products like plywood or fibre cement
• Compatible with prefabricated wall and floor cassettes

Figure 1: Timber Framed Construction (Speedpanel and USG Boral) (WS TDG 01 p5)

2.2 Massive Timber Systems 

Overview:
Mass timber refers to any timber element with a minimum cross-section thickness ≥75 mm. This includes products like CLT, Glulam panels, and thick LVL, which form structural walls, floors, or roofs. Mass timber systems can be used across all building classes, and has been used successfully in Australia in domestic houses, commercial offices, industrial warehouses, residential apartments, hotels, resorts, and civic buildings.

Panel-Based Systems
CLT and other panelised systems are used for loadbearing walls, floors, and roofs. They are dimensionally stable and suitable for prefabrication.

Post-and-Beam Systems
Massive Glulam or LVL members are used in grid layouts to support long-span roofs and open-plan interiors.

Figure 2: CLT Construction (Strongbuild) (WS TDG 16 p7)

2.3 Post-and-Beam Construction

Overview
This system uses discrete vertical and horizontal members (columns and beams) to form a structural frame. It is ideal for buildings requiring long spans or flexible internal layouts, such as offices, halls, or commercial tenancies.

Features

• Typically uses Glulam or LVL for structural members
• Allows for exposed timber interiors with visual-grade finishes
• Compatible with prefabricated infill walls, floor panels, or roof diaphragms

Figure 3: Post and Beam construction (Chifley Business Park - Goodman)

2.4 Prefabricated and Modular Timber Construction

Overview
Prefabricated systems use off-site manufacturing to deliver walls, floors, and even complete room modules (volumetric units). This approach improves quality control, reduces site labour, and shortens construction timelines.

System Types

• Panelised: wall, floor, and roof cassettes including insulation and services
• Volumetric: 3D modules like hotel rooms or classrooms craned into place
• CLT Modular: increasingly used for mid-rise housing and repeatable units

Figure 4: Prefabricated timber walls being assembled by Modscape + Modbotics automation

Key Takeaways

• Light timber framing remains the most common solution for housing and low-rise buildings, supporting fast, cost-effective construction.
• Mass timber systems (CLT, Glulam, LVL) provide robust structural solutions for mid-rise and hybrid buildings, with integrated fire and acoustic design potential.
• Post-and-beam systems support long spans and flexible layouts, especially in commercial and institutional projects.
• Choose the system based on building type, span needs, and construction logistics-not just product type.

Timber’s lightweight nature, prefabrication potential, and fire-resistant capabilities make it an ideal material for modern, sustainable construction across all major building classes.

Timber construction systems are now used across nearly all NCC building classes-from detached houses to mid-rise apartments and large-span commercial buildings. Each building type places different demands on timber systems in terms of structure, fire resistance, durability, acoustics, and moisture control.

This section outlines the most common structural approaches by building class, with links to deeper design guidance.

What are the building classes?

Figure 1: Building Classes (NCC)

3.1 Class 1a - Domestic or Residential Building and Class 1b - Boarding House, Guest House or Hostel

Typical systems:

• Light timber frame with timber trussed roofs
• Joisted or cassette timber floors
• Timber decking, stairs, and window joinery

Advantages:

• Fast, cost-effective construction using widely available materials
• Compatible with prefabricated wall and roof panels
• Readily meets Deemed-to-Satisfy (DTS) solutions for fire and energy compliance
• Supports high-performance detailing for thermal comfort and passive design

Performance:

• NCC-aligned framing and detailing guides are widely available
• Requires moisture-aware detailing at subfloors, balconies, and cladding interfaces
• H1 or H2-treated framing required in some regions

3.2 Class 2 - Domestic Apartment Building

Typical systems:

• Fire-protected CLT and LVL wall and floor systems (up to 25 m effective height)
• Light timber frame construction for 3-4 storey walk-ups
• Cassette floors, modular bathrooms, and prefabricated wall assemblies

Advantages:

• Rapid construction using prefabricated timber systems
• Reduced structural weight supports vertical extensions and soft-soil sites
• Excellent acoustic separation and thermal performance with correct build-ups
• Lower site disruption for infill and tight-access developments

Performance:

• NCC Volume 1 permits fire-protected timber construction up to 8 storeys
• Acoustic performance must be designed to meet Rw + Ctr and Ln,w targets
• Vapour control is critical in sealed or highly insulated buildings

3.3 Class 3 - Long Term or Transient Accommodation

Typical systems:

• Concrete or steel podium
• Timber residential levels above using CLT or lightweight timber framing
• Separation layers for fire and acoustic compliance between use types

Advantages:

• Efficient vertical zoning with lightweight superstructure
• Simplified detailing at interfaces with properly coordinated hybrid systems

Performance:

• Requires fire separation and acoustic decoupling between Class 5/6 and Class 2/3 zones
• Structural interfaces must manage differential movement and moisture exposure

3.4 Class 4 - A Single Domestic Dwelling within a Non-Residential Building

Typical systems:

• Concrete or steel podium, typically forming the primary structural and fire-separation platform below.
• Timber residential construction above, using either CLT floors/walls for efficient acoustic and fire performance or lightweight timber framing for cost-effective layouts.
• Dedicated separation layers between the commercial and residential parts of the building, including fire-rated ceilings, acoustic underlays, service penetrations with FRL-rated collars, and decoupled floor/ceiling systems.

Advantages:

• Efficient vertical zoning, with the lightweight timber residential structure reducing overall load on the podium and simplifying foundation design.
• Simplified detailing at interfaces with properly coordinated hybrid systems

Performance:

• Fire separation and acoustic decoupling between the Class 5/6 areas below and the Class 2/3 dwelling above must follow NCC Volume 1 requirements, including FRL floor systems, smoke separation, and compliant service penetrations.
• Structural interfaces must accommodate differential movement between the stiff podium and the more flexible timber superstructure, including allowance for shrinkage, creep, and moisture-related movement in CLT or light framing.
• Moisture management is critical at the podium–timber junction, with membranes, upstands, drainage paths, and ventilation zones ensuring timber elements are protected from ponding, vapour drive, or water ingress.

3.5 Class 5: Offices

Typical systems:

• Glulam or LVL post-and-beam frame
• CLT or cassette floor systems
• Integrated acoustic and services zones within floor build-ups

Advantages:

• Long-span layouts with minimal internal supports
• Visual-grade timber enhances biophilic and wellness outcomes
• Prefabrication supports tight construction timelines and low-disruption upgrades

Performance:

• Fire compliance via encapsulation or Performance Solution with charring
• Acoustic zoning required between tenancy levels and meeting spaces
• Column-fire detailing and floor edge sealing are essential for NCC compliance

3.6 Class 6: Shops and Retail Premises

Typical systems:

• Portal frames (Glulam or LVL)
• CLT or cassette floors over shop fitouts
• Structural plywood for bracing and sheathing

Advantages:

• Open spans and flexible layouts
• Faster tenancy turnover with dry construction and minimal wet trades
• Reduced roof weight for suspended signage, services, or solar integration

Performance:

• NCC fire and smoke separation may require encapsulation or hybrid elements
• Impact sound and footfall vibration in mezzanine levels must be addressed

3.7 Class 7: Car parks & Warehouses

Typical systems:

• Glulam or LVL portal frames providing long, unobstructed spans suitable for vehicle circulation, racking, or storage layouts.
• Timber floor or mezzanine systems, often using CLT panels or LVL joist floors, particularly in light-industrial fitouts, offices-over-warehouse layouts, or inspection platforms.
• Structural plywood or OSB bracing to form shear walls or roof diaphragms, delivering efficient wind-load transfer in large-volume buildings.

Advantages:

• Rapid erection times, with large portal frames and prefabricated wall/roof elements
• Lower embodied carbon compared with steel-only structures, with excellent long-term durability where moisture exposure is controlled.

Performance:

• Fire Performance Solutions are commonly required, particularly for open-deck carparks, warehouse fire compartments, or where storage loads trigger higher FRL requirements. Charring calculations, partial encapsulation, or hybrid solutions may be needed.
• Moisture and durability management is essential, especially in carparks or semi-exposed warehouses. Timber elements must be detailed to avoid ponding, splash zones, chemical exposure, or vehicle-induced dampness.
• Vibration and deflection control must be considered for CLT mezzanines or timber floors, particularly where forklifts, trolleys or vehicles operate above or below.

3.8 Class 8: Factories and Production Facilities

Typical systems:

• Glulam or LVL portal frames for long-span manufacturing halls, assembly areas and covered work zones.
• CLT mezzanines, control rooms or internal office pods, providing stiff, lightweight intermediate floors with rapid installation.
• Structural plywood or OSB bracing walls and roof diaphragms, supporting wind and seismic load transfer across large building footprints.
• Hybrid structures, where steel is used locally for high-temperature or high-load zones and timber is used for the main envelope, mezzanines or ancillary areas.

Advantages:

• Fast construction with minimal wet trades, supporting early equipment installation and staged commissioning of plant or production lines.
• Lightweight superstructure, reducing loads on foundations and often improving performance on soft soils or brownfield sites with existing footings.
• Low embodied carbon and good internal environmental quality, particularly in clean manufacturing or laboratory-adjacent spaces that benefit from stable, low-vibration timber floors.

Performance:

• Fire Performance Solutions are frequently required, as Class 8 buildings often contain elevated fire loads, combustible goods, process heat sources or hazardous chemicals. Encapsulation, charring design, or sprinkler integration may be necessary.
• Chemical, moisture and abrasion resistance must be addressed, particularly in areas subject to wash-downs, chemical handling, humidity, or heavy equipment movement. Protective linings or sacrificial layers may be required.
• Vibration and dynamic response require assessment where machinery, conveyors or plant equipment operate on or adjacent to timber floors or mezzanines.
• Service integration and penetrations must be carefully coordinated, as factories often require complex ducting, electrical trays, compressed air lines, extraction systems and large plant openings that pass through or interface with timber elements.

3.9 Class 9 Public Buildings

Typical systems:

• CLT floors, walls, and roofs for modular classrooms or permanent facilities
• Glulam/LVL post-and-beam with acoustic soffits and ceiling systems
• Structural ply or OSB for bracing in hybrid applications

Advantages:

• Quiet, warm, and healthy interiors support concentration and occupant wellbeing
• Speed of construction suits school holidays or tight programs
• Modules can be delivered pre-lined with integrated services

Performance:

• NCC Volume 1 acoustic, fire and crowd safety requirements apply
• Mass timber systems require moisture protection and post-install inspection access

3.10 Class 10 Non-Habitable Buildings

Typical systems:

• Light timber framing for garages, sheds and small utility structures.
• Glulam/LVL portal frames for larger-span carports or farm structures.
• Structural ply or OSB for bracing and simple wind-load resistance.
• Timber decking, pergolas and small ancillary elements.

Advantages:

• Simple, cost-effective construction with fast assembly.
• Well suited to prefabrication or incremental extensions.
• Low embodied carbon compared with steel alternatives.

Performance:

• Wind and uplift design must reflect local site conditions and exposure.
• Durability detailing is essential, especially for partially exposed structures.
• Fire separation requirements may apply near boundaries or adjacent dwellings.
• Interfaces with Class 1 buildings must manage moisture, drainage and load paths.

Key Takeaways

• Timber systems suit all NCC classes, from detached housing to industrial and public buildings, with solutions ranging from light framing to CLT and glulam/LVL portals.
• Prefabrication and MMC approaches consistently improve speed, cost, quality and site efficiency across residential, commercial and industrial projects.
• Fire and acoustic performance are the major determinants of system choice in mid-rise residential, mixed-use and commercial classes, often requiring encapsulation or hybrid assemblies.
• Moisture management and durability are critical across every class, particularly at interfaces (balconies, podium junctions, semi-exposed industrial zones and Class 10 structures).
• Structural interfaces and movement control matter in hybrid buildings, where timber is combined with concrete or steel.
• Large-span commercial and industrial buildings rely on LVL/glulam portal frames, CLT mezzanines and strong diaphragm/bracing systems for wind and vibration performance.
• Light timber framing remains the most economical and widely adopted option for Class 1 dwellings, small structures and low-rise residential buildings.
• Performance Solutions for fire, acoustics and industrial risk profiles are common in Classes 5-9, where higher loads, occupancy types or hazards exceed DTS pathways.

Understanding timber’s structural, fire, acoustic, and environmental performance ensures safe, compliant, and long-lasting timber buildings in modern construction.

Timber is a high-performance construction material and its behaviour under load, moisture, fire, sound, and thermal stress must be well understood and carefully managed. This section provides a concise overview of key performance areas in timber design and construction.

Each topic summarised here is explored in greater technical depth on dedicated subpages.

4.1 Structural Strength and Stability

Overview
Timber products-especially engineered products like CLT, LVL, and Glulam-offer excellent strength-to-weight ratios and can be used for both short-span and long-span structural systems.

Design Considerations

• CLT panels act as diaphragms and loadbearing plates
• LVL and Glulam act as high-performance beams and columns
• Framed systems rely on bracing and fixing patterns to resist racking and wind loads
• Creep, shrinkage, and interface movement must be accounted for in long-term design

4.2 Moisture Resistance and Durability

Overview
Timber is hygroscopic-it absorbs and releases moisture in response to humidity, rain, vapour diffusion, and condensation. Moisture is a defining factor in long-term serviceability.

Design Considerations

• Moisture above 20% enables fungal decay and corrosion of fasteners
• End grain must be sealed, and cavities must be ventilated
• Vapour-permeable membranes and drainage paths reduce risk
• Timber selection must match durability class and hazard exposure

For more information see the Moisture Guide and the Durability Guide

4.3 Fire Performance

Overview
Timber-especially mass timber-performs predictably in fire due to its insulating char layer. Modern detailing allows timber buildings to meet Fire Resistance Levels (FRLs) up to 90 or 120 minutes.

Design Considerations

• CLT must be encapsulated or protected, or justified via Performance Solution
• Glulam and LVL require minimum section thickness or linings for compliance
• Charring rates and adhesive behaviour are critical in design
• Cavity barriers, penetrations, and joints must not undermine system integrity

4.4 Acoustic Performance

Overview
Timber’s low mass can lead to sound transmission unless layered and decoupled effectively. Acoustic detailing is essential in multi-occupancy buildings and schools.

Design Considerations

• Floors require floating screeds or suspended ceilings to control impact noise
• Walls should use staggered studs, batts, and double linings to manage flanking
• Penetrations (e.g. GPOs, pipes) must be sealed to maintain Rw ratings
• NCC requires compliance with airborne and impact sound targets for walls and floors

4.5 Thermal Performance and Energy Efficiency

Overview
Timber provides natural insulation and enables high-performance thermal assemblies. It supports net-zero energy goals with reduced thermal bridging and high airtightness.

Design Considerations

• Mass timber buffers internal temperature swings (thermal mass)
• Lightweight framing enables high R-value insulation in walls and roofs
• Detailing at junctions must prevent thermal bridging or air leakage
• Vapour control layers must be placed according to climate zone

Key Takeaways

• Timber systems must be designed with awareness of moisture, fire, and acoustic risks, especially in tightly sealed, multi-storey, or high-humidity applications.
• Mass timber systems must address detailing at joints, interfaces, and cavities for fire, acoustic, and moisture compliance.
• Durability depends on matching species or treatment class to the exposure risk, with good drainage and ventilation.
• Thermal and energy efficiency is a strength of timber, especially when prefabricated systems are sealed and detailed with care.

By integrating engineering, protective detailing, and compliance strategies, timber buildings can achieve exceptional durability, fire safety, sound insulation, and energy efficiency, ensuring long-term functionality and sustainability.

Timber buildings rely on a diverse array of connection systems to ensure strength, stability, and serviceability. From traditional joinery to modern engineered fasteners, the right connection method depends on the product type, structural system, and exposure conditions.

This section outlines the main categories of timber connections and how they’re applied across different building systems. More detailed design and fabrication guidance is provided in linked subpages.

5.1 Mechanical Fasteners

Overview
Mechanical fasteners are the most common connection type across light timber framing, engineered wood, and mass timber systems. They provide structural fixity, ease of installation, and flexibility on site.

Applications

• Nails: Framing, sheathing, decking
• Screws: CLT panels, flooring, concealed connections
• Bolts: Post-and-beam joints, long-span trusses, hybrid interfaces
• Self-tapping screws: Mass timber assemblies, including diagonal and inclined fasteners for moment resistance

Design Considerations

• Embedment length, edge distance, and spacing determine capacity
• Fastener material must be compatible with timber treatment (e.g. HDG or stainless for H3+ treated pine)
• Pre-drilling is recommended in dense or appearance-grade hardwoods

Figure 1: Some common types of nails and screws

5.2 Metal Connectors (Plates, Brackets, Hangers, Dowel Systems)

Overview
Metal connectors provide increased load-carrying capacity and can simplify assembly in both light and heavy timber systems.

Applications

• Gang-nail plates: Prefabricated trusses

Figure 2: Gang-nail plate (ITSCP Offsite)

• Joist hangers: Floor and deck framing

Figure 3: Joist hanger (Victorian Timber & Building Supplies)

• Brackets and angle plates: Post-to-beam or wall-to-floor junctions

Figure 4: Angle Bracket (Simpson Strong-Tie)

• Dowel-type connectors: High-strength connections in Glulam or CLT

Figure 5: Dowel Connector (F. Solarino et. al.)

Performance Notes

• Connections must allow for movement and seasonal shrinkage
• In fire-rated applications, connectors may need to be embedded or protected by charring timber or linings
• In exterior or moist environments, galvanised or stainless steel is required to prevent corrosion

5.3 Adhesive and Composite Bonding

Overview
Adhesives are used extensively in engineered wood products and increasingly in panel-based connections. They enable strong, invisible joints and improve air-tightness and vibration performance.

Applications

• CLT and LVL manufacture (PUR, MUF, PRF adhesives)
• Glued scarf or finger joints in long-span members
• Site-applied glues for acoustic or vapour sealing at CLT interfaces (used selectively)

Considerations

• Adhesive compatibility with coatings, treatments, and structural movement must be confirmed
• Site bonding requires tight moisture and temperature control to ensure curing and bond strength

5.4 Traditional Timber Joinery Methods

Overview
Although less common in commercial buildings, traditional joinery techniques are still relevant in architectural projects, restoration works, and dowel-laminated timber (DLT) systems.

Examples

• Mortise and tenon
• Lap and scarf joints
• Timber-only dowel and peg connections

Advantages

• No reliance on metal components-minimises thermal bridging and avoids galvanic corrosion
• Suits exposed timber architecture, heritage repairs, or carbon-sensitive design philosophies

5.5 Prefabrication and On-site Assembly Techniques

Overview
Prefabricated timber elements are precision-manufactured off-site and assembled rapidly on-site with pre-defined connection details. Connection accuracy and sequencing are critical for speed and performance.

Key Elements

• CLT panel edge profiles (half-laps, splines, scarf joints)
• Pre-installed hardware or sleeves for concealed connections
• Shop-drawn fastener locations to minimise site adjustment

Assembly Considerations

• Site tolerances must account for timber movement and minor misalignments
• Weather protection is essential during assembly, especially for CLT and Glulam
• Crane planning, lift points, and temporary bracing must be coordinated early

Key Takeaways

• Connection types vary by system: nails and screws in light framing; bolts, dowels, and concealed fixings in mass timber.
• Fire resistance, moisture exposure, and movement must be considered in connection detailing.
• Prefabrication requires exact tolerances and well-coordinated sequencing of connection points.
• Corrosion resistance is critical when working with treated timber or exposed environments.

Timber connections are essential for ensuring structural strength, fire compliance, durability, and construction efficiency. Understanding the right connection method for each timber system enables safe, cost-effective, and long-lasting timber buildings.