Pitching the perfect roof
It is important to understand that the roof pitch influences both the look and functionality of a building. It's crucial to balance design preferences with practical considerations that impact the roof's performance and the project's cost. In this article, you'll find insights and tips to help you make informed roof pitch choices and learn how Fielders® roofing products can help you achieve the perfect roof.
What is roof pitch?
You’ll no doubt already know roof pitch refers to the angle or slope of a roof, expressed as the ratio of the roof's vertical rise to its horizontal span (run). This measurement is crucial as it affects the roof's aesthetic appeal, drainage efficiency, and overall structural integrity. A steeper pitch is typically associated with a more traditional look and better water runoff, while a lower pitch is often used for modern designs and may require special waterproofing measures.
In Australia, roof pitch is commonly expressed in degrees or as a ratio (e.g., 20° or 1:3). When using the ratio method, it is usually written as the vertical rise over a standard horizontal run of 1 meter (1000 mm). For example, a roof with a 300 mm rise over a 1-meter run would have a pitch ratio of 300:1000 or 1:3.
Why is roof pitch important?
Adequate positive fall prevents ponding, which can lead to a reduced service life and diminished rainwater capacity, especially in severe environments.
At low slopes, all roof supports must be perfectly aligned because even slight variations can result in zero or negative fall. These issues may arise during construction or after completion due to construction tolerances, settlement, timber warping or shrinking, or additional loadings such as air conditioners or suspended surfaces.
Factors related to roof pitch
Functionality:
- HVAC systems: Roof pitch affects the space available in the ceiling cavity for heating, ventilation, and air conditioning units. Steeper roofs offer more vertical space for larger HVAC systems, while flatter roofs may limit internal installation options, sometimes requiring external placement.
- Solar panels: The roof angle is important for solar panel efficiency. Optimal angles vary by location and sun exposure. Flatter roofs may need tilt frames to achieve the best angle, ensuring maximum sunlight capture and energy efficiency.
- Building height: Flatter roofs help meet local height regulations and minimise shadows on neighbouring properties, reducing planning compliance issues.
Cost:
- Material costs: Steeper pitches increase the roof's surface area, requiring more materials and higher costs. This also applies to the internal framing, adding to overall expenses.
- Labour and safety: Installing steeply pitched roofs is more complex and hazardous, necessitating additional safety measures and specialised equipment, leading to higher labour costs.
Drainage:
- Water dispersal: Steeper roofs facilitate faster water runoff, reducing leak risks. Flatter roofs need well-designed gutter systems to manage water pooling, which, if inadequate, can lead to structural damage.
Wind and fire resistance:
- Cyclonic areas: Roof design in cyclonic regions must meet specific standards to withstand high winds, requiring specialised fasteners and additional fixings for structural integrity.
- Bushfire zones: In bushfire-prone areas, roofs with a pitch of 18° or greater help prevent debris accumulation, reducing fire risk. Steeper pitches facilitate quick debris clearance, enhancing fire safety.
Fielders offers a range of profiles suitable for different roof pitches, ensuring that you have the perfect fit for any project, from residential to commercial buildings.
Some of our Australian made roofing profiles include:
S-Rib™ - Iconic corrugated roofing
The iconic corrugated profile that has stood the test of time. Equally at home on heritage projects through to the most contemporary designs, S-Rib™ Corrugated is the economical choice for roofing applications. Light weight and easy to install, S-Rib™ for pitches as low as 5° (1 in 12), ideal for hip and gable roofs.
Learn more about S-Rib Corrugated
TL-5 - Functional, economical rib and pan style roofing
TL-5™ is both versatile and economical while still providing a clean and crisp modern finish thanks to its trapezoidal ribs and refined fluting in the pans. TL-5™ has a nominal cover width of 762mm and is suitable for roof pitches as low as 2° (1 in 30), making it perfect for flat sections like skillion roofs, porches, and verandahs.
KingKlip® - Concealed fixed roofing with superb watertightness
KingKlip® profiles suit all facets of modern architecture due to their strong rib appearance and crisp, clean finish. This concealed fixed profile delivers strong, uninterrupted lines across the large roof wall areas. With superb watertightness KingKlip® profiles are suitable for near flat roofs down to 1 degree (1 in 50) pitch.
The Finesse® range
Fielders Finesse® range provides a stylish suite of profiles, including standing seam, nailstrip, and interlocking panel styles, perfectly suited for contemporary architectural roofing or walling applications. Manufactured from COLORBOND® steel, the Finesse® range offers options in COLORBOND® steel Matt and COLORBOND® Metallic finishes, allowing you to make a bold statement or subtly blend into the environment. Profiles in the Finesse® range are suitable for roof pitches as low as 1°.