Pitch perfect: Lysaght’s tips for every roof pitch
You would be well aware that roof pitch impacts both the aesthetic and functional outcomes of a building. You not only need to ensure that the roof meets design preferences but also consider practical aspects that affect the overall performance and cost of the project.
This article provides insights and tips that can assist you in making informed roof pitch decisions and how LYSAGHT® roofing profiles can help you nail the right roof.
What is roof pitch?
Roof pitch (or slope) indicates how many inches the roof rises for every 12 inches in depth. For example, a "6/12 pitch" means the roof rises 6 inches for every 12 inches it extends inward towards the peak.
To measure roof pitch, you can either:
- Mark a level at 12 inches on the roof surface and measure the distance to the roof while keeping the level balanced, or
- Measure from the underside of the rafters at the overhang, gable end, or in the attic for a more accurate result.
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.
Why is roof pitch important?
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.
For more information, read our full article below:
Considerations for the Pitch of the Roof on Your Home
Profile-specific roofing solutions
Lysaght offers a range of profiles tailored to different roof pitches, ensuring that you have the perfect fit for any project, from residential to commercial buildings.
Some of our high-quality roofing profiles include:
CUSTOM ORB® - Classic, versatile corrugated steel roofing or walling
Delivering a textured visual with its uniform ‘ripple’, CUSTOM ORB® is the famous and original LYSAGHT® corrugated profile, often imitated but never matched. This lightweight and economical profile offers versatility by being laid flat or sprung curved, making it suitable for both traditional and contemporary architecture. CUSTOM ORB® can be used for pitches as low as 5°, ideal for hip and gable roofs.
TRIMDEK® - Versatile roof and wall cladding
TRIMDEK® features bold, trapezoidal ribs and subtle fluting in the pans, making it ideal for commercial, industrial, and residential buildings. TRIMDEK® has a nominal cover width of 762mm and is suitable for roof slopes as low as 2°, making it perfect for flat sections like skillion roofs, porches, and verandahs.
KLIP-LOK® - Clip fixed steel roofing or walling for supreme watertightness
KLIP-LOK® features a substantial, bold rib rising from wide, fluted pans, creating a distinctive linear visual. Its concealed fixing system ensures superb watertightness, making it ideal for near-flat roof planes on large commercial and industrial buildings or low-pitched rooflines on residential buildings.
ZENITH® Range - Inspired by Europe, designed for Australia
Lysaght’s ZENITH® 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 ZENITH® 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 ZENITH® range are suitable for roof pitches as low as 1°.