Repair Systems — 03 — Facade & External Envelope
Code 4 milled lead cavity flashing
Supplier reference for Code 4 milled lead cavity flashing (1.8mm, 20 kg/m²) for masonry facade remediation on Class 2 strata buildings. The standard lead code for cavity flashing above lintels, at sill courses, and at the base of cavity — self-sealing laps, coastal-grade durability, and fully workable on site.
What is Code 4 milled lead cavity flashing?
Code 4 milled lead sheet (1.8mm, 20 kg/m²) is the standard specification for cavity flashing in most standard masonry remediation applications — base of cavity, over lintels, and window sill courses in residential and Class 2 strata buildings where the cavity width and exposure conditions fall within Code 4 capacity.
Product Reference
2 products — 2 suppliers — Code 4 milled lead cavity flashing — scroll to view all
Midland Lead Australia — Code 4 Milled Lead Sheet
Code 4 milled lead sheet — standard cavity flashing
System Description
Midland Lead Australia supplies Code 4 milled lead sheet rolled to standard cavity flashing widths. Supplied in roll lengths of 3m or 6m. Lead is self-sealing at overlaps under thermal movement. Weep formers are rolled from the same sheet on site or supplied as separate folded lead units. The leading UK-origin milled lead product in the Australian market, Midland Lead is available through plumbing and building materials merchants nationally. Confirm current stock widths, roll lengths, and pricing with local merchant before specifying.
Technical Properties
- Code: Code 4 — standard cavity flashing grade
- Thickness: 1.8mm
- Weight: 20.41 kg/m²
Limitations
- Heavier than aluminium — consider roof access for delivery of lead rolls to high levels
- Not suitable for direct contact with zinc-coated or galvanised steel without isolation strip — bimetallic corrosion risk
- Lead fatigue cracking risk in high-vibration environments — not typical for standard masonry facades
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Austral Lead — Code 4 Milled Lead Sheet
Code 4 milled lead sheet — Australian supply
System Description
Austral Lead supplies Code 4 milled lead sheet through plumbing and building materials merchants across Australia. Product is equivalent to Midland Lead specification — Code 4, 1.8mm, 20 kg/m². Availability varies by state and merchant — confirm with local merchant before specifying. May require substitution with Midland Lead in some states where Austral Lead is not stocked.
Technical Properties
- Code: Code 4 — standard cavity flashing grade
- Thickness: 1.8mm
- Weight: 20.41 kg/m²
Limitations
- Availability varies by state — confirm with local merchant before specifying in documents
- Not a national brand — may require substitution with Midland Lead in some states
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Comparison
Side-by-side comparison of Code 4 milled lead cavity flashing suppliers. Confirm all product selections with current supplier before specifying.
| Supplier | Product | Code | Thickness | Weight | Distribution | Key feature | Primary use |
|---|---|---|---|---|---|---|---|
| Midland Lead | Code 4 Milled Lead Sheet | Code 4 | 1.8mm | 20 kg/m² | National — Midland distribution network | Leading Australian market supplier | Standard cavity flashing — lintel, sill, base of cavity |
| Austral Lead | Code 4 Milled Lead Sheet | Code 4 | 1.8mm | 20 kg/m² | Plumbing merchants — state-dependent | Australian supply chain | Standard cavity flashing — residential and low-rise |
Do not confuse Code 4 lead flashing with:
- Code 5 lead flashing (2.24mm, 25 kg/m²) — heavier grade for parapets, exposed ledges, and wide-cavity applications — listed on the Code 5 lead flashing page
- Code 6 heavy duty lead flashing (2.65mm, 30 kg/m²) — for the most demanding applications including parapet copings in exposed coastal locations — listed on the Code 6 lead flashing page
- Code 3 lead flashing (1.32mm) — lighter grade not typically used for cavity flashing in masonry facades — more common in internal DPC applications
- Aluminium cavity flashing — lighter, lower-cost, but not self-sealing at laps and not suitable for all coastal applications — listed on the cavity flashing — aluminium page
- Alcore composite flashing — bitumen-aluminium laminate, different thermal and installation properties — listed on the cavity flashing — Alcore page
Disclaimer
This page provides general technical information only. Lead code selection, flashing width, lap detail, and weep former spacing must be confirmed by a qualified remedial practitioner against project-specific conditions and AS 3700.