Hoop Iron for Lintels
Lintels above doors and windows are critical structural elements. Hoop iron reinforcement around these openings prevents the diagonal cracking that commonly occurs at the corners of openings.
Why Lintels Need Hoop Iron
When load is transferred around an opening, stress concentrates at the corners. Without hoop iron, diagonal cracks (called "stepping cracks") develop from the corners of windows and doors. Hoop iron distributes this stress and holds the masonry together.
Placement Guide
- Run hoop iron continuously above the lintel for at least 300mm beyond each side of the opening
- Place hoop iron below the sill of windows, extending 300mm beyond each side
- Install hoop iron at every course from the lintel to 3 courses above the opening
- At door frames, run hoop iron down the sides of the opening as well
Recommended Products
30mm x 0.6mm galvanised hoop iron is standard for residential lintel reinforcement. Use 30mm x 0.8mm for commercial buildings or openings wider than 1.5m.
Frequently Asked Questions
How far should hoop iron extend past a lintel?
Hoop iron should extend at least 300mm beyond each side of the opening, both above the lintel and below window sills.
Why do cracks appear above doors and windows?
Cracks at openings occur because load from above must transfer around the opening, creating stress concentrations at the corners. Proper hoop iron reinforcement prevents these cracks by distributing the stress.
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