Installing a whirlybird on a corrugated roof is a smart and efficient way to improve ventilation in your home, shed, or commercial building. Whirlybirds, also known as turbine vents, spin with the help of wind and create suction to draw out hot air from roof cavities. This helps regulate temperature and reduce moisture buildup inside. Especially in warmer climates or metal-roofed buildings, installing a whirlybird can significantly reduce indoor heat and lower energy costs. While the process may seem technical, it is entirely achievable with the right tools, safety precautions, and step-by-step guidance.
Tools and Materials Needed
- Whirlybird vent kit
- Electric drill
- Metal cutting shears or jigsaw with a metal blade
- Measuring tape
- Marker or pencil
- Silicone roofing sealant
- Roofing screws with rubber washers
- Screwdriver or impact driver
- Safety harness and ladder
- Gloves and safety glasses
Preparation Before Installation
Inspect the Roof
Begin by checking your corrugated roof for any signs of damage or rust in the area where you plan to install the whirlybird. Choose a spot close to the roof’s peak, as this allows the vent to extract the hottest air efficiently. Avoid areas obstructed by beams or rafters beneath the roof sheet.
Choose the Right Size
Whirlybirds come in different sizes. For most residential buildings, one 300mm (12-inch) whirlybird is sufficient for every 90 to 100 square meters of roof space. For larger spaces or those with poor airflow, consider installing more than one.
Marking and Cutting the Hole
Locate the Position
From the rooftop, use a measuring tape and marker to mark the center where the whirlybird will be installed. Ideally, place it on a flat portion of the corrugated panel, between the ridges, for a better seal. Make sure the spot is centered between internal roof supports and accessible for installation.
Cut the Opening
Using your drill, create a pilot hole in the center of your marked circle. Then, insert metal cutting shears or a jigsaw to cut a circular hole large enough to fit the turbine base. Be cautious and wear gloves to protect your hands from sharp metal edges.
Installing the Whirlybird Base
Insert and Position the Flashing
Most whirlybird kits include a flashing plate designed to sit under the vent and conform to the contours of the corrugated roof. Slide the flashing under the metal sheet above the hole, with the lower edge sitting over the roof sheet below the hole. This overlap directs rainwater away from the hole and prevents leaks.
Secure the Base
Once the flashing is in position, apply a generous bead of silicone roofing sealant along the edge where it meets the corrugated sheet. Press the flashing down firmly. Then, use roofing screws with rubber washers to fasten the flashing to the roof sheet, securing each corner and along the perimeter for a tight fit.
Attach the Turbine
Fit the Turbine Vent
The spinning turbine portion fits onto the top of the base pipe. Most models come with adjustable bases and pre-drilled holes. Place the turbine over the base and align it according to the wind direction if necessary. Ensure it sits straight and level for optimal rotation.
Secure the Turbine
Use the screws provided in the kit to attach the turbine to the base. Tighten them firmly but avoid over-tightening, which could warp the metal or restrict spinning. Once secured, give the turbine a gentle spin to check for smooth movement.
Sealing and Waterproofing
Apply Additional Sealant
To prevent water infiltration, apply roofing silicone around the base of the flashing and any exposed screws. Pay special attention to seams and joints. This extra sealant layer acts as a barrier against wind-driven rain and debris.
Inspect for Gaps
Look around the vent installation to ensure there are no gaps or misalignments. Gaps can cause leaks or reduce the effectiveness of the whirlybird. Make necessary adjustments and seal as needed.
Test the Ventilation
Observe Functionality
After installation, allow a day or two for weather conditions to test the whirlybird naturally. On a breezy day, check from the ground that the turbine is spinning freely. Inside the attic or ceiling cavity, you should feel a draft or change in air movement.
Monitor Indoor Temperature
Over the next several days, observe any differences in indoor heat levels, especially during peak sunlight hours. A functioning whirlybird should help lower the temperature and reduce stuffiness in your building.
Maintenance Tips
- Inspect the whirlybird every 612 months to ensure it spins freely and is not obstructed by debris.
- Clean the vent periodically, especially after storms, to remove leaves or bird nests.
- Check the sealant and screws for signs of deterioration and reapply or tighten if needed.
- Lubricate the bearing mechanism if the turbine becomes noisy or stiff.
Common Mistakes to Avoid
- Installing too low on the roof, reducing ventilation effectiveness
- Failing to use sealant, leading to roof leaks
- Incorrectly aligning the flashing, allowing water to enter
- Not securing the turbine tightly, causing noise or wobbling
- Skipping safety precautions when working at height
Installing a whirlybird on a corrugated roof is a practical and affordable way to enhance roof ventilation. With proper tools, a thoughtful approach, and attention to sealing and placement, this project can be completed in just a few hours. Whether you’re looking to cool your attic, reduce mold risk, or improve air circulation, a whirlybird is a worthwhile addition to your home or building. Always prioritize safety during the installation, and perform regular maintenance to ensure the vent continues working efficiently for years to come.