The building stock
Hawthorn holds a substantial stock of interwar brick apartment buildings — face brickwork, rendered detailing, generous proportions — much of it now under heritage overlay and nearly all of it approaching or past a century old. Postwar walk-ups and contemporary infill fill in around it.
What we actually find here
Lintel jacking is the signature defect. Interwar buildings used mild steel lintels over window and door openings, frequently with minimal protection and modest cover. As the steel corrodes it expands, lifting the masonry above and producing stepped cracking that follows the mortar joints. Owners read it as settlement; it is corrosion, and the distinction matters because the repairs are completely different.
The tell is location: cracking that starts at the corners of openings and steps upward and outward is lintel-driven. Settlement cracking has a different geometry and usually a different distribution across the building.
Previous repairs frequently made it worse. The common history here is a repoint in hard cement mortar over the cracks, done some decades ago. It conceals progression, damages the softer original brick at the arrises, and traps moisture against the very steel that is corroding.
Face brickwork demands matched repair. Where units have to come out to replace a lintel, they should go back — numbered, reclaimed and reinstated in position, in a mortar matched by analysis rather than by eye. Done properly the elevation reads as original because it is.
Cavity ties. Corroding lintels usually mean corroding wall ties at the same detail line, because they were installed in the same era to the same standards. Investigating one without checking the other leaves half the problem in the wall.
Structural involvement
Lintel replacement on a multi-storey masonry building is temporary-works engineering, not bricklaying. Masonry above the opening needs support while the lintel comes out, and the sequence has to account for what the wall is carrying. On Hawthorn’s interwar stock we scope this with the engineer and document it, because the failure mode when it goes wrong is not cosmetic.
Heritage considerations
Significant fabric and heritage overlays are widespread here. Where they apply, the methodology needs to support permit conditions: reclaimed units reinstated in position, analysed mortars, galvanised or stainless replacement lintels isolated from the masonry, and a sample panel approved before full application. We prepare the documentation as part of the scope rather than treating it as somebody else’s problem.