Press H — or click the roof icon in the toolbar — choose a form from the buttons at the top of the panel, then drag a rectangle over the building. The corners snap to the outer wall faces, and the ridge runs along the long side. Everything else is edited after placing.
A roof is a parametric object, not drawn geometry: one solve feeds the plan, the elevations and the 3D view at once, so they can never disagree about where the ridge is.
The nine forms
Flat, Mono-pitch, Gable, Hip, Pyramid, Half-hip, Gambrel, Mansard and Butterfly. Switching form keeps the footprint and adopts sensible parameters for the new shape, so trying four of them over the same building costs four clicks.
Compound roofs are made by overlapping several roofs rather than by a special tool: two gables crossing at right angles merge into a cross-gable, with the valley worked out for you. Draw the second roof over the first and they solve as one form.
The controls that matter
| Field | What it does |
|---|---|
| Wall plate | The height of the roof’s underside at the wall line, measured from this storey’s floor. Raising it is the raised heel that lets a flat ceiling run out to the wall. |
| Pitch | 1–80° from horizontal. A gambrel or mansard splits this into Upper pitch, Lower pitch and Break at (where the slope changes, as a percentage of the half-span). |
| Ridge at | Gable only — move the ridge off centre for a saltbox. On a butterfly the same control reads Valley at. |
| Hip depth | Half-hip only — how far down the end the hip cuts. |
| Overhang | 0–2000 mm all round. A flat roof can tick Overhang per side and set Top, Right, Bottom and Left separately. |
| Ridge level | Not a field — a readout at the top of the panel, in millimetres above the storey floor. It is the fastest check that a roof clears what is under it. |
Walls follow the roof
You do not cut the walls to the slope by hand. A wall under a pitched roof is built up to the roof’s underside, gable infill included, so the elevation and the 3D model show the real triangle of wall above the plate. Change the pitch and the walls follow on the next solve.
Where you want a flat ceiling under all that, draw one — see ceilings, which also explains what happens where the slope dips below the ceiling near the eaves.
What this doesn’t do
- No curved, domed or sawtooth roofs, and no dormers. The nine forms above are the whole set; a dormer has to be faked with a second small roof.
- A roof belongs to a storey. Its wall plate is measured from that floor’s level, so moving a roof between storeys means redrawing it.
- Skylights are roof openings, not windows. They do not appear in the window schedule.
Next
Ceilings for what happens underneath, and elevations for reading the pitch off the drawing.