Ever wondered what that black layer is near the bottom of a brick wall? Chances are it's a damp proof course, or DPC. Most homeowners don't give DPCs a thought until there's a damp problem, but they play an important role in keeping your home dry and preventing damage.
DPCs are made of materials water can't pass through, like polyethylene, bitumen or metal. They're built into the wall above finished ground level, separating the masonry in contact with the ground from the wall and floors above, so dampness can't climb up into your home.
Under the NCC Housing Provisions, the DPC generally has to sit at least 150 mm above the adjacent finished ground level. That can drop to 100 mm on sandy, well-drained sites, 75 mm above a finished paved or concrete surface, or 50 mm where that paving is protected from the weather by a carport or veranda.
C11 - Enclosed Stage Inspection Checklist
$119.00 AUD
Last updated 21 Oct 2026 · Revision 5 · Free updates for life
Checklist Type: Major (Enclosed Stage)
Form Factor: Fillable, print-ready PDF (A4, 35 pages)
When to use: Enclosed (lock-up) stage: brickwork and external cladding
A 152-point enclosed stage checklist for brick veneer and fibre cement, weatherboard or foam cladding. Check the cavity, ties, flashings, windows and lintels before the linings hide them.
DPC or Cavity Flashing?
DPC flashing is covered in some detail—though not with absolute clarity—in AS4773.2 Masonry for Small Buildings.
The standard mainly says the flashing must be continuous or have minimum laps to maintain integrity. Another key point: a flashing that extends right through the masonry is considered a DPC (as in a cavity flashing).
So, at a step, you can use a compliant material (refer to Table 5.2) for the flashing step (if it's a big step), along with a separate DPC lapped to meet the requirements.
The material you choose depends on the house's exposure classification (how close it is to breaking surf) and the DPC location (see Table 5.2 below).
If you use metal flashings, avoid dissimilar metals (two different metals in contact can corrode each other). Interestingly, some termite barriers also work as DPCs when they meet the requirements. Termite companies point this out in their specifications as a selling point (why their system is awesome).
Page 22 of 4773.2:
| Rule | What it means on site |
|---|---|
| Use a listed material | Every flashing and DPC must be one of the materials in the next table. |
| Rigid where it holds a shape | If the flashing has to keep a fold or upstand, use a rigid material, not a soft membrane. |
| Avoid mixing metals | Metal flashings must suit the metals they touch or that water runs onto or off, or they corrode. |
| No lead on drinking-water roofs | Lead flashings are not used on a roof that feeds a rainwater tank for drinking water. |
| No lead with zinc-aluminium | Lead and zinc-aluminium coated steel are never used together. |
| Membrane DPC | Either a DPC to AS/NZS 2904, or a sheet-metal termite shield (AS 3660.1) run continuously through the wall with penetrations sealed. |
| One part can do both jobs | A flashing that runs right through the masonry can also act as the DPC. |
Summarised in our words from AS 4773.2-2015 Clause 5.6. Check the current edition.
Page 23 of 4773.2:
| Where | Suitable materials (minimum) |
|---|---|
| Inside the wall, not exposed to weather | Embossed polyethylene (0.5 mm before / 0.75 mm after embossing); polyethylene-coated aluminium (0.5 mm overall); bitumen-coated aluminium (0.56 mm overall); bitumen-coated copper (0.41 mm overall); copper 0.5 mm; galvanised steel 0.6 mm; annealed lead 10 kg/m², pieces no longer than 1.5 m |
| Exposed to weather | Bitumen-coated aluminium (0.81 mm overall); bitumen-coated copper (0.41 mm overall); copper 0.5 mm; galvanised steel 0.6 mm; annealed lead 20 kg/m², pieces no longer than 1.5 m |
| Saline (salty) ground | Embossed polyethylene; polyethylene-coated aluminium; bitumen-coated aluminium (0.81 mm overall) |
| Class A or S sites on free-draining sand or limestone | A proprietary polymer emulsion DPC parged onto the slab |
Summarised in our words from AS 4773.2-2015 Table 5.2. Check the current edition.
Page 49 Clause 9.6 of 4773.2:
"DPCs shall be stepped such that continuity is maintained where a change in floor or ground level occurs." Notes (on Page 49) also say - "A flashing that extends through the entire width of a masonry leaf may also be used as a DPC."
| Frame type | Single storey (mm) | Two storey (mm) |
|---|---|---|
| Fully seasoned frame, joists and bearers | 0 | 0 |
| Seasoned softwood walls, unseasoned softwood floor | 0 to 10 | 10 to 20 |
| Unseasoned softwood walls, seasoned floor | 5 | 11 |
| Unseasoned hardwood walls, seasoned floor | 9 | 22 |
| Unseasoned hardwood walls, unseasoned softwood floor | 9 to 19 | 32 to 42 |
| Seasoned softwood walls, unseasoned hardwood floor | 0 to 22 | 20 to 42 |
| DPC height above: finished ground | 150 min | 150 min |
| Paving or concrete sloping away from the wall | 75 min | 75 min |
| Paving under a carport or veranda | 50 min | 50 min |
Shrinkage: first figure is slab-on-ground, second is timber floor. Summarised in our words from AS 4773.2-2015 Table 9.1 and Clause 9.6.1. DPCs run through the full leaf, stay visible at the wall face and lap 150 mm min.
Page 50 of 4773.2:
And Page 51 of AS4773.2:
Page 61 repeats that "DPCs shall be stepped such that continuity is maintained where a change in floor or ground level occurs, as shown in Figure 10.1." The main takeaway: keep the DPC continuous and maintain minimum laps (150 mm).
Stepped DPCs
AS 3700 Masonry Structures also covers DPCs, but not in the detail of AS 4773.2. It mostly just says "you need to have one to prevent moisture."
👉️ DPC: A DPC is a continuous horizontal barrier that stops moisture rising up through walls by capillary action (rising damp). In brick veneer it usually sits in a mortar joint near the bottom of the wall, at the minimum heights above ground covered earlier (generally 150 mm above finished ground).
In typical brick veneer (brick external skin + frame internal wall) residential house construction, the DPC is often 300mm-wide polyethylene, lapping the brick width and fixed to the wall frame with the wall wrap lapping over it (by 150mm) once installed.
Example of a DPC
A wide cavity flashing can serve as a DPC if it extends from the inner wall face to the outer brickwork, draining moisture through the weep holes (as shown in the images below).
👉️ Cavity Flashing: A cavity flashing catches water that gets into the cavity, usually from wind-driven rain or leaks, and sends it back outside through the weep holes. It's typically installed at window heads, sills and base courses.
A Typical Cavity Flashing Detail
Termite Barrier: If the termite barrier isn't a DPC, then yes, you'll need both a termite barrier and a DPC. Many builders combine the DPC with the cavity flashing in a brick veneer facade, as shown in the detail below, so it does both jobs. Some termite systems like Termi-Mesh need the first course of brickwork laid before the mesh is parged (stuck on with a mortar render) to the slab edge rebate and taken over the top of the first course of bricks.
Other termite barriers, like Kordon or chemically impregnated sheet barriers, are fixed to the top of the slab before the wall frames are stood, then brought through the cavity and over the first course of bricks.
With Termi-Mesh, the cavity flashing/DPC goes over the top of the mesh barrier and extends to the outer face of the brickwork (see image below).
Physical Termite Barrier And Brick Veneer
Below are some window installation manuals with details showing cavity flashings (head and sill flashings) around window and door openings.
Window Installation Manuals: Flashings Around Openings
The head and sill flashings (the sill flashing collects the jamb flashings) drain to weepholes in the facade.
In short: a DPC is usually only one masonry unit wide and stops rising damp, while a cavity flashing drains water from inside the cavity to the outside through the weepholes.
👉️ When a cavity flashing doubles as the DPC, as it often does in house construction, it's very important that the cavity is clean and not "full of mortar dags". The cavity is supposed to be a consistent width, no less than 40mm, and kept clear so moisture can drain down to the flashing and out through the weepholes.
In effect, it's a drain and ventilation system for the space between the back of the brick wall and your internal wall frame.
Further Reading
Brick Veneer Facades: A Complete Guide for Aussie HomesBrick veneer facades are a popular, durable, and generally low maintenance option for your home façade. In this post we cover all the essential elements and best practices in brick veneer wall construction.
Exploring the 8 Types of Brick Masonry in House ConstructionBrick masonry is a popular choice for house construction due to its durability, aesthetics, and flexibility. But did you know there are eight different types of brick masonry that can be used? Each type has its own unique characteristics that make it suitable for different applications.
Efflorescence on Concrete & Brick: Prevention & TreatmentEfflorescence, the white powdery substance on concrete and brick surfaces, can be a homeowner’s nightmare. Caused by water seeping through and evaporating, it’s not just unsightly but can indicate deeper issues. Dive into understanding its causes, prevention, and effective treatments.
Mastering Mortar Mixes: Key to Successful Masonry MortarThis article covers the essential balance of cement, lime, and sand needed for a strong, durable mortar. It discusses the role of water, admixtures like plasticizers, and advanced techniques to enhance mortar strength. Learn how to achieve the perfect consistency for your masonry projects.
Understanding Concrete Laitance: A Homeowner’s GuideLaitance is the weak, milky or powdery layer of cement dust, lime and sand fines that appear on the surface of concrete. Read more about how & why this happens.
Can You Lay Dirty Bricks? Your Rights ExplainedCan muddy bricks be laid? This post breaks down what the Australian Standards, NCC, and best practices say—and what to do if it’s happened on your build. The answer isn’t as clear-cut as you might expect.
Types of Sand in Construction: A Comprehensive GuideLearn about various types of sand used in construction, including river, concrete, and manufactured sand. This guide breaks down their unique properties, uses, and importance in building processes, from concrete mixtures to plastering, offering a clear understanding for beginners.
