Typhoon-Resistant Roof Design: One-Sided Roofs

1. One-Sided Roof Characteristics

• Also known as: Mono-pitch, shed roof, or skillion roof
• Description: Single sloping plane, usually with a steep pitch
• Common uses: Modern architectural designs, additions to existing structures

2. Typhoon Resistance Considerations

2.1 Advantages

• Simple design with fewer seams, reducing potential water entry points
• Can be designed with a steep pitch for effective water shedding
• Fewer edges for wind to catch compared to more complex roof shapes

2.2 Challenges

• Large surface area can experience significant uplift forces in high winds
• Asymmetrical design may lead to uneven wind loads on the structure
• Potential for increased wind-driven rain penetration on the high wall

3. Design Recommendations for Typhoon Resistance

3.1 Pitch and Orientation

• Optimal pitch: 30-45 degrees
• Orient the low end towards the prevailing wind direction if possible

3.2 Structural Reinforcement

• Use hurricane straps to secure roof to walls
• Implement robust roof-to-wall connections, especially at the high wall
• Consider using a structural ridge beam for added strength

3.3 Roofing Materials

• Use impact-resistant materials (e.g., metal roofing, concrete tiles)
• Ensure proper overlap and fastening of roofing materials
• Install a fully-adhered underlayment for additional water resistance

3.4 Overhang and Edges

• Minimize roof overhangs (ideally less than 50 cms/20 inches)
• Use aerodynamic edge details to reduce wind uplift

3.5 Ventilation

• Implement pressure-equalized soffit vents
• Consider ridge venting systems designed for high-wind areas

3.6 Water Management

• Install larger gutters and downspouts to handle heavy rainfall
• Use multiple downspouts to distribute water flow

4. Additional Considerations

• Ensure compliance with local building codes for high-wind areas
• Conduct wind tunnel testing or computational fluid dynamics (CFD) analysis for complex designs
• Consider the entire building envelope in the design, not just the roof
• Regular maintenance and inspections are crucial for long-term performance

5. Alternative Roof Designs for Comparison

• Hip roof: Generally considered more typhoon-resistant due to its sloped sides
• Gable roof with low pitch: Can be vulnerable to uplift in high winds
• Flat roof: Can be designed for high-wind resistance but requires careful detailing for water management