Repair Systems — 03 — Facade & External Envelope
Engineer-designed in-situ or custom precast concrete lintel
Reference for engineer-designed in-situ or custom precast concrete lintels for non-standard masonry openings on Class 2 strata buildings. Covers local precast manufacturers and specialist structural precast fabricators — used for non-standard spans, complex loading, heritage facades requiring profile-matched sections, or any opening where standard or prestressed precast cannot meet the structural or geometric requirements. Full structural engineer design from first principles is mandatory.
What is an engineer-designed custom precast or in-situ concrete lintel?
An engineer-designed concrete lintel is designed from first principles by a structural engineer — specifying the concrete grade, section dimensions, reinforcement layout and bar sizes, cover, and bearing details — then manufactured as a custom precast element or cast in-situ. This approach is used for non-standard opening spans, complex structural loading, heritage facades requiring profile-matched sections, or any situation where standard or prestressed precast sections cannot meet the project's structural or geometric requirements.
Supplier Reference
2 fabricator types — engineer-designed custom precast concrete lintels — scroll to view all
Local Precast Manufacturers — Custom Precast to Engineer's Specification
Custom precast concrete lintel — engineer's specification — local manufacturer — AS 3600
System Description
Local precast concrete manufacturers supply custom precast lintels to the structural engineer's specification — any section geometry, reinforcement layout, concrete grade, and cover can be specified. This route is used for non-standard opening spans, unusual structural loading, heritage facades requiring custom section profiles, or any situation where standard stock precast sections cannot meet the project requirements. The structural engineer designs the lintel from first principles — specifying section dimensions, reinforcement bar sizes and layout, concrete cover, concrete grade, and bearing plate details. The manufacturer produces the element to the engineer's drawings. Crack control requirements at the lintel-to-masonry interface should be considered by the engineer — particularly for remedial masonry applications where the surrounding masonry may have differential movement characteristics.
Technical Properties
- Any section geometry and reinforcement layout — not constrained to standard precast manufacturer profiles
- Engineer controls concrete cover, grade, and mix design — optimised for the specific exposure classification
- Heritage compatible — section can be profiled, pigmented, or textured to match existing masonry
Limitations
- 2–6 week lead time for custom manufacture — programme must allow for manufacturing time before delivery
- Requires a complete engineer's drawing for every lintel — significant design time required before ordering
- Variable quality control compared to national manufacturers — inspect every lintel on delivery for dimensional conformance, cracks, and reinforcement cover
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Specialist Structural Precast Fabricators — Non-Standard Section Profiles
Non-standard custom precast lintel — specialist fabricator — complex profiles — AS 3600
System Description
Specialist structural precast fabricators manufacture non-standard precast lintels with complex section profiles — including rebated sections, shaped soffits, T-sections, L-sections, and lintels with embedded structural inserts. Used for heritage facades where the original opening had a non-rectangular lintel profile, or for structurally complex applications where the loading or geometry requires a custom section that a standard precast manufacturer cannot produce. The structural engineer provides a complete design package including section drawings, reinforcement schedule, concrete mix specification, cover requirements, and bearing details. Confirm crack control requirements for the lintel-to-masonry interface with the engineer — particularly important for heritage and remedial masonry applications. Allow 3–8 weeks lead time for specialist fabrication.
Technical Properties
- Complex section profiles available — rebated, shaped soffit, T-section, L-section, or any engineer-specified geometry
- Embedded structural inserts possible — steel bearing plates, lifting anchors, and connection elements can be cast in
- Heritage compatible — section profile and finish can match original non-standard lintel geometry on heritage facades
Limitations
- 3–8 week lead time for specialist fabrication — longer than standard or local precast; confirm before committing programme
- Highest cost of all precast lintel options — complex moulds, specialist formwork, and non-standard reinforcement all add cost
- Requires a complete structural engineer's design package before fabrication can begin
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Fabricator Comparison
Side-by-side comparison of engineer-designed custom precast fabricators. Structural engineer design package required before ordering from any fabricator.
| Fabricator type | Product | Profile | Lead time | Heritage | Cost | Primary use |
|---|---|---|---|---|---|---|
| Local precast manufacturers | Custom precast lintel | Standard or simple custom | 2–6 weeks | Rendered / pigmented | Moderate | Non-standard spans and openings |
| Specialist precast fabricators | Non-standard section lintel | Complex — any profile | 3–8 weeks | Profile-matched to original | High | Heritage / complex section profiles |
Do not confuse engineer-designed precast with:
- Standard reinforced precast lintel — stock sections from Hume Concrete, BGC Concrete, and local manufacturers — use for standard opening spans and loads where stock sections meet the engineer's requirements; engineer-designed custom precast is only needed when stock sections cannot be used
- Prestressed precast lintel — factory-prestressed sections for long-span or high-load openings — Stresscrete and specialist prestress fabricators — more efficient than reinforced for long spans; choose before resorting to fully custom first-principles design
- Steel lintels (stainless, duplex, galvanised) — thin section metallic lintels — lighter than concrete, no custom precast lead time; engineer should confirm whether steel is appropriate before selecting custom concrete
- Masonry arch reconstruction — structural alternative to lintel over heritage openings; heritage engineer must assess arch option before specifying any lintel replacement
Disclaimer
This page provides general technical information only. Engineer-designed concrete lintel design, section dimensions, reinforcement, cover, crack control, and bearing details must be specified and certified by a structural engineer for each specific opening from first principles per AS 3600 and AS 3700.