In short: A lintel is designed to deflect. The clearance above a window frame is the room it needs to do that without loading the window.
Deflection is designed in
Every structural member deflects under load. A lintel over a window opening is expected to, within limits. The clearance between the lintel and the window frame is what allows that movement without transferring load into a frame that is not structural.
What failure looks like
Windows that become difficult to operate, cracked glass without impact, distortion in the frame, and cracking at the corners of the opening. All of it appears well after handover and reads like a window problem rather than a structural clearance problem.
Checked with a tape
It is a measurement at lock-up or PCI, before the finishes close the gap up. We record it as a finding on Wollert builds across Lyndarum North, Mason Quarter and the surrounding City of Whittlesea releases.
Written by the Owner Inspections team from inspections carried out in Wollert. Licensed building practitioners, Building & Plumbing Commission registration CDB-U 53425.
