Box Gutters

Box gutters are the single most failure-prone element of any building — undersized, poorly fallen or badly detailed, they cause more internal water damage than any other roof component. ONTRA designs and fabricates every box gutter to AS/NZS 3500.3, with hydraulic calculations for catchment area, correctly sized overflows, and generous falls to sumps and rainheads. We fold from Colorbond, zinc or stainless steel in continuous lengths where possible to minimise joints, and we detail expansion joints, drops and outlets to prevent the ponding and back-flow that destroys ceilings. Done once, done properly.

Every box gutters project at ONTRA follows the same process: site inspection, written scope, fixed-price quote, fabricated and installed by our in-house team, and signed off with a final photo report.