One wall’s area is its length × its height. Click the wall and the properties panel gives you both in millimetres — divide each by 1000 and multiply, and you have the area of one face in m². Two ways to skip the arithmetic, both Pro: select a room and the panel reads out the wall surface enclosing it, or open Tables in the top bar and choose Quantities for every wall in the plan grouped by build-up. Openings are deducted in both.
One wall, by hand — free
- With the select tool, click the wall. The panel is headed Wall.
- Read Length and Height, both in mm. A wall with no height of its own shows the storey’s default — the Wall height field under New wall defaults, which starts at 2700 mm on a new plan.
- Convert and multiply. A 5000 × 2700 wall is 5.0 m × 2.7 m = 13.5 m² for one face.
- Take the openings off. A standard door is 900 × 2100 = 1.89 m²; a standard window is 1200 wide between a 900 sill and a 2100 head, so 1.2 × 1.2 = 1.44 m². The wall above becomes 11.61 m² with one door in it.
- Plastering or painting both sides? Double it.
Length is measured on the centreline, end to end, which is how the wall is drawn. Where a wall butts into another its centreline runs half the other wall’s thickness past the face, so adding up panel lengths by hand double-counts the junctions. The Quantities table corrects that; your calculator doesn’t.
One room’s walls — Pro
The surface you paint, plaster or tile is measured per room, not per wall. A room here is an area: draw one with the area tool (A), or press Detect rooms in that tool’s panel to find every closed room on the floor.
- With the select tool, click the room. The panel is headed Area.
- Floor area is the m² of the floor. Wall area underneath is the wall surface enclosing it.
- The line under the figure breaks it down. A 5.7 × 3.7 m room in 300 mm walls at the default 2700 head, with one 900 door in it, reads 48.87 m² over “50.76 m² gross less 1.89 m² of openings · 18.80 m of wall face” — the gross rectangle, what the openings took off it, and how much wall the room actually runs along.
Every room at once is on the Rooms tab of Tables, which gains a Wall
area column beside Floor area, with both totalled at the foot. Hover a
figure for the same breakdown. On the free plan the column is there and reads
Pro.
A room’s boundary is the wall face, so the area you draw is what gets measured. An area traced across an open-plan threshold has boundary with no wall behind it: that stretch is reported as open in the breakdown rather than counted, and an area drawn clear of every wall reads no walls on the boundary instead of a confident 0.00 m².
Where a room runs along both sides of a partition standing inside it — a peninsula, a stub off a wall — both faces are counted, because both get finished.
The Room schedule sheet prints both columns: tick it in the export dialog and it comes out with per-floor subtotals, a grand total, and the same caveats on the paper.
The whole plan at once — Pro
Press Tables in the top bar, then the Quantities tab. The first section
is Walls, one row per build-up — or per thickness, as 200 mm wall, for
walls that carry no build-up — with the number of walls in the group and two
columns:
| Column | What it is |
|---|---|
| Run | Centreline length in m, corrected at junctions: an L-corner splits between both walls, a T-stem is measured to the face of the wall it meets, and where two walls cross, the through wall is measured full and the other loses the crossing once. |
| Face area | One face, storey-rectangular, openings deducted, in m². |
The sheet says so itself, under the table: “Measured quantities, not a cost estimate: one wall face, openings deducted, junctions counted once (T-stems to the face, crossings interrupted). Recomputed live; prints as its own sheet.”
Nothing is stored, so a quantity can never be out of date with the drawing. Tick Quantities in the export dialog to print it as its own sheet — see exporting to PDF.
Areas of material, not just of wall
A wall that carries a build-up also feeds the Materials (from build-ups) section, where each layer is counted at the wall’s face area: boards and finishes in m², bulk materials in m³. That is the number to order plasterboard or insulation against, and it comes out of the same face area — so the two sections can never disagree.
What the number means
- It is one face. Two sides of the same wall means twice the area.
- Walls are measured as rectangles, storey by storey. The triangle of a gable above the wall head is not in the total. Dimension it on the elevation with M and add ½ × base × height yourself.
- Openings come off at their full structural size, not at the size of the glass or the leaf.
- The totals cover the whole document — every storey, not the floor you are looking at.
- A wall spanning a split level is measured taller, from the lowest slab beneath it, because that is how it is built. A room’s walls are measured from that room’s own floor instead, so a sunken living room reads taller than the hall next to it — which is what you are painting.
- A room counts only its own side of a wall. Two rooms either side of a partition each measure their own face; the same wall in Quantities is one face for the whole building.
For external walls only, with a U-value against each one, use the heat-loss sheet — it measures the same faces the same way and shows only the envelope.
What this doesn’t do
- No per-wall row in the table. Quantities groups walls by build-up. For one specific wall, select it and multiply.
- Selecting several walls does not total them — the panel offers thickness and height to apply to all of them, not a sum.
- No pricing, no waste or lap allowance, no paint coverage. It is a bill of quantities: what is drawn is what is counted. Add your own allowance.
- A room with no area drawn is not measured. The wall area follows the area zone, so a space you never named or detected has no row.
- A ceiling drawn lower does not shorten a room’s walls. Wall area runs to the wall head either way; take the difference off yourself.
- No split by finish. One figure per room — not tiled m² against painted m². The breakdown gives you the run in metres, so a skirting or cornice length is the perimeter it states.
- Metric only. Areas are m² everywhere and there is no square-feet option — see feet and inches.
- Floor area is a different question. It sits in the column beside the wall area on the Rooms tab — see schedules.
Next
Quantity takeoff is the rest of that sheet — roof covering, slab, openings, decking and paving — and build-ups and U-values is what turns a wall area into a materials list.