Blog ·
Wall thickness in Australian houses: double brick, cavity, veneer and stud
A floor plan measured from inside (with a tape, a laser or a LiDAR scan) gives you room sizes. To join the rooms into a house, you need the thickness of the walls between them. Get it wrong and every room after the first drifts a little further out.
Typical thicknesses
| Wall | Made of | Typical thickness |
|---|---|---|
| Internal double brick | Two leaves of 110 mm brick, rendered | about 230 mm |
| External cavity brick | 110 mm brick, 50 mm cavity, 110 mm brick | about 270 to 290 mm |
| External brick veneer | 110 mm brick, cavity, 90 mm timber or steel frame, plasterboard | about 250 to 260 mm |
| Internal single brick or block | One leaf of 110 mm brick or block, rendered | about 130 to 150 mm |
| Internal stud | 70 or 90 mm frame, plasterboard both sides | about 90 to 110 mm |
These are typical, not guaranteed. Older houses vary, render adds thickness, and renovations mix systems.
How to tell what you have
- Measure at a doorway. The door frame shows the full wall thickness. This is the quickest and most reliable check.
- Knock. Stud walls sound hollow between the studs; brick does not.
- Age and place. Double brick has long been common in Perth, and many older Adelaide houses are solid brick or stone. Brick veneer with stud walls inside became the usual way to build across most of Australia from the 1960s and 70s. Extensions are often built differently from the original house.
Mixed houses
It is common for an older house to be double brick with a later extension in lighter construction. In Plotlay's Square up rooms, pick a wall type and click each wall section that is that type; each pair of rooms can have its own thickness. Outside walls are lined up but not thickened, because a scan only sees their inside face.
More from the blog
- How to put a floor plan on a satellite map, to scale
- Measure a house with an iPhone LiDAR scanner
- Find your property boundary online, free (SA, VIC, QLD and TAS)
- Why satellite images don't line up (and what to trust instead)
- Drawing a site plan for a council or development application
- Overlay renovation plans on your floor plan and compare layouts