Roof Decision: Cut Roof vs. Truss Roof
1. Cut Roof
- Description: Custom-cut on-site, allowing for future attic conversion.
- Cost: Generally more expensive due to labor and materials.
- Flexibility: Offers more adaptability for future changes.
2. Truss Roof
- Description: Prefabricated and lifted into place with a crane.
- Considerations: Requires early supplier involvement for design integration.
- Precision: Trusses are precision-engineered, so all rooflights and openings must be included in the design.
Roof Timber Spacing
- Standard Spacing: Roof timbers, including trusses, are often spaced at 400mm centers for standard materials.
- Increased Spacing: Spacing can be increased to 450mm or 600mm, which may reduce timber costs but requires thicker plasterboard and larger timber sections.
Structural Supports and Foundations
- Timber Frame: Requires on-site foundations and subfloor before erection. The timber frame company can specify foundation details.
- Architectural Designer: An experienced designer can help avoid early manufacturer commitments and ensure that foundation and structural requirements are met.
Foundation Options:
- Standard Foundation: Traditional and widely used.
- Insulated Foundation: Offers better thermal performance but may impact structural drawings and load-bearing requirements. Early site assessment is recommended.
Upper Storey Construction
1. Timber Flooring
- Advantages: Cost-effective but can be challenging to control sound transmission.
- Considerations: Requires careful soundproofing measures.
2. Hollow Core Concrete Slabs
- Advantages: Provides excellent sound insulation and thermal mass.
- Considerations: More expensive and heavier, necessitating additional structural support. Not as straightforward for routing services.
Staircase and Flooring Choices
- Staircase Material: Decide between timber or concrete, as this affects structural implications.
- Prefabricated Joists: Offer better acoustic performance and easier routing of services. They can be a good alternative to solid timber or concrete floors.
Screeds and Insulation
- Screed Specification: Based on floor structure and finished floor level. Ensure insulation and screed thickness are specified by the engineer.
- Timber Floors: Must support the screed load, with soundproofing considerations.
- Engineered Joists: Designed to handle screed loads but come at a higher cost.
Large Open Spans and Glazing
- Additional Supports: Large spans or cantilevers need extra structural support, often involving more steel, which increases costs.
- Steel Lintels: Required for large sections of glazing, adding to expenses.