Why Wood

Timber Fundamentals: Design-to-Production Principles

Introduction

The document highlights the sustainability aspects of timber, its material properties, structural applications, and engineered wood products. The goal is to present a comprehensive understanding of how timber is utilized in modern construction while addressing environmental and structural challenges.

Why Choose Wood?

Wood is a unique construction material offering numerous benefits:

• Natural CO2 reduction and storage: A single project (7,700 m³ of timber) can store 7,700 tons of CO2, equivalent to 76 million km driven by car.

• Thermal insulation and moisture control: Balances indoor humidity and provides a comfortable environment.

• Prefabrication efficiency: Reduces on-site construction time through controlled manufacturing processes.

• Process safety and innovation: CNC machining and digital modeling enable precise assembly and integration with other building systems.

• Product safety: Natural fire resistance through charring creates an insulating layer, maintaining structural integrity during fire events.

Sustainability Aspects

Carbon Reduction

Wood construction contributes significantly to reducing CO2 emissions, both through carbon sequestration and lower embodied energy. Sustainable forest management is crucial to maintaining wood availability and ecological balance.

Life Cycle Analysis

Timber products are recyclable and reusable. This includes:

• Pre-consumer waste recycling: Minimizes waste during production.

• Post-consumer recycling: End-of-life products can be repurposed or used for energy recovery.

Timber as a Material

Timber’s anisotropic nature means that it behaves differently based on grain orientation. The following table highlights the differences between various timber types in terms of strength:

Strength Class	Bending Strength (N/mm²)	Tension Strength (N/mm²)	Compression Strength (N/mm²)	Example Material
C22	22	13	20	Poplar (Softwood)
C24	24	14	21	Spruce (Softwood)
C30	30	18	23	Larch (Softwood)
D30	30	18	23	Oak (Hardwood)
D35	35	21	25	Beech (Hardwood)

Engineered Wood Products

Engineered wood products enhance the structural capabilities and efficiency of timber construction. Key products include:

• Glued Laminated Timber (GLT): Multiple layers of timber glued together to form a strong composite.

• Cross Laminated Timber (CLT): Stacked boards glued in alternating directions for strength.

• Laminated Veneer Lumber (LVL): Thin layers of wood veneers bonded under pressure.

• Oriented Strand Board (OSB): Compressed layers of wood strands arranged in specific orientations.

• Plywood: Thin layers of wood veneers arranged with alternating grain directions.

Strength Characteristics of Engineered Wood

Product	Bending Strength (N/mm²)	Tension Strength (N/mm²)	Compression Strength (N/mm²)
GL24	24	19.2	20
GL28	28	22.3	21
LVL48P	48	35	23

Timber Quality and Moisture Management

Timber quality is heavily influenced by moisture content and drying processes:

• Green Timber: Moisture content > 30%

• Semi-Dry Timber: Moisture content 20%-30%

• Dry Timber: Moisture content < 20%

Proper drying enhances timber strength, reduces weight, and lowers shipping costs. Wood that is properly dried can increase strength and stiffness by up to 50% compared to its green state.

Hybrid Timber Solutions

Combining timber with concrete or steel improves structural performance and longevity. Hybrid structures leverage the strengths of both materials, such as combining the compressive strength of concrete with the flexibility of wood.

Conclusion

Timber construction remains at the forefront of sustainable building practices, offering flexibility, strength, and environmental benefits. Advanced engineered wood products and hybrid solutions continue to expand the possibilities for modern timber architecture.