Building Materials: Selection, Compatibility, and Environmental Impact
1. Common Building Materials in Sydney
Concrete blocks are commonly used for underground car parks, reinforced with polycloth and membrane for waterproofing.
2. Building Materials and Their Properties
a) Common Building Materials
Concrete:
- High compressive strength, hardness, and durability
- Low permeability, water cement ratio, and good resistance to water absorption
- Excellent fire resistance
Steel:
- Soft and malleable, can be drawn into wires and thin sheets
- Strong, ductile, and easy to work with, suitable for rolling into sections, strips, and sheeting
- Hard but less ductile, typically used for structural purposes
b) Quality Standards
Quality checks should consider:
- Fit for purpose, useful life expectancy, and service requirements
- Appearance, size, and quantity
- Price and cost
- Maintenance specifications and storage requirements
c) Compatibility and Non-Compatibility
Compatibility is crucial for the longevity of structures. For example:
- Galvanized bolts on weathering steel initially sacrifice zinc to form a protective rust layer, preventing further corrosion.
- Copper pipes and lead flashing should not contact ZINCALUME or COLORBOND steel, as their properties can cause accelerated corrosion.
3. Environmental Impact of Building Materials
Uncontrolled timber use, particularly hardwoods from mass deforestation projects, can lead to:
- Land instability
- Soil erosion
- Climate change
- Disturbance of wildlife balance
4. Allowable Tolerances for Naturally Occurring Materials
Materials like timber and clay in bricks exhibit changes in stress, strain, and elasticity due to environmental factors. Allowable tolerances account for these changes, ensuring structural integrity.
5. Tolerances for Installing and Assembling Materials
Australian Standard HB31-2002 provides general tolerances for building construction, considering member capacity and industry capabilities. Control joints and allowable moving space/joints are important considerations.
6. Professional Builder’s Approach to Material Selection
Builders consider:
- Final product analysis and expectations
- Comparison of materials with criteria
- Material type, size, shape, finish, preservation, and fastening methods
- Structural, environmental, and energy ratings
- Budget and site conditions
- Sustainability
7. On-Site Process
[Specific on-site process not provided in the original text]
8. Important Factors for Builders
- Safety: Preventing injuries
- Fire Resistance Rating: Compliance with BCA for fire safety
- Serviceability: Fit for purpose and durability
- Cost Effectiveness: Maximizing profit within customer budget
9. Material Degradation
a) Timber Degradation
Short-term: Insects, borers, fungi, fire
Long-term: Weathering, causing aesthetic rather than structural issues
b) Material Selection and Building Life Cycle
Architects and designers select materials to achieve desired performance within budget. Builders consider:
- Final product analysis and expectations
- Comparison of materials with criteria
- Material type, size, shape, finish, preservation, and fastening methods
10. Process and Documentation for Builders
Builders use:
- Building contract
- Written specification
- Relevant Australian Standards
- Building code meeting performance requirements
Changes require approval from relevant project authorities.
11. Organizational Procedures
a) Procedures
- ITP for purchase verification
- SWMS for safe material handling
- Up-to-date MSDS for incident management
b) Communication
- Training
- Induction
- Site diary
12. Transportation Limitations and Effects
Builders must consider:
- Distances between transport access and building site
- Manufacturer and supplier responsibilities for material delivery
- Builder’s responsibility for site delivery
- Delivery schedules and programs for smooth and effective delivery