Stairs
Pick a stair from pictures – straight, one to three turns, spiral or the loft stair – and see how it measures up against the stair rules.
In the video0:39
How to do it
Choose Stairs (S). In the bar at the top, open the stair type and pick one from the pictures: straight, a quarter turn, a half turn, two turns, three turns round a stairwell, a spiral or the loft stair.
Click where the bottom step goes, then click in the direction you walk up. The flights are sized from the storey height so every step fits the step rule.
Select the stair to change it in the panel on the right: its type, what each turn has – a landing, winders or balanced winders – the width, the length of each flight, which way it turns and the number of risers. “Even steps” gives every step the same going again.
Under “Steps and railing”, set the nosing, open risers, the stringers – closed, cut or one in the centre –, what the treads are made of – oak, beech, pine, painted, stone, concrete or steel – and the railing: on the open sides, on the left, on the right, on both sides or none. Its height follows your country’s rule unless you give it another. Then the handrails: on the left, on the right or on both sides – as your country asks unless you choose – and whether the stair is shared by several homes.
The stair rules at the bottom of the panel say how the stair measures up: the step rule, the going, the width – a little more for a stair that turns on its steps, where the country asks –, the headroom under the floor or roof above, the going at the narrow end of winders where your country has a rule, the railing’s height and the gaps between its balusters, and handrails on both sides where your country asks for them. A stair shared by several homes is checked against the values for one. The Rule check tab sums up the stairs too.
Good to know
- Balanced winders spread the turn over several steps before and after it, so the going on the walking line stays the same and no step narrows to a point. They need about as much room as winders round a newel, and walk almost like a straight flight.
- The loft stair has half treads that alternate left and right: steep and narrow, for a loft that isn’t a main room or as an extra way up. The home’s main way up needs an ordinary stair. In Germany and Finland it is checked against the looser rule for a stair that isn’t the required way up.
- With open risers, Norway, Sweden and Ireland allow at most 100 mm between the treads: the check says when the openings need closing or a bar.
- Where no railing runs, the handrail goes on the wall: 3D shows it on brackets, its ends turned to the wall, and the material list counts it and its brackets. Norway, Sweden and Finland ask for handrails on both sides, Ireland on a stair wider than 1 m; Sweden lets one do where a second isn’t needed. A stair shared by several homes in Norway gets two on each side, at 0.9 m and 0.7 m.
- The plan shows the walking line with its arrow, and a break line where the plan cuts the stair, 1.5 m up; the steps above it are dashed. On the plan of the floor above, the stair is drawn from the break line up, through the stairwell, so the two plans show it once. A handrail on the wall is a thin line along the steps. In 3D you can walk up it, and the sections show the treads, the stringers and the railing.
- Or ask the assistant: “a samba stair up to the storage loft”, “a stair with two turns round a stairwell”, “make the steps balanced”, “open risers and a railing on both sides” or “handrails on both sides and beech treads”. It fits the stair into the room with floor in front of the bottom step and past the top one, and says how it measures up. See The assistant.
Questions and answers
How steep may a stair be?
It depends on the country. In Norway (TEK17 § 12-14) a stair inside a home should have 2 risers + 1 going of 600–640 mm and a going of at least 250 mm on the walking line; other countries limit the riser, the going or the step rule their own way. Choose the country in the project settings, and the stair rules follow it.
Can a loft stair be the only way up?
Not to the home’s main rooms. A stair with alternating treads is for a loft that isn’t a main room – storage, say – or as an extra way up. If there are bedrooms or a living room up there, the main way up needs an ordinary stair, and the check says so.
What are balanced winders?
A way to turn without a landing. Instead of steps fanning out from a newel post, the turn is shared by the steps before and after it, so every step has the same going on the walking line and the narrow ends stay wide enough. The app balances them by the classic development method and checks the narrow end where the country has a rule – in Germany at least 100 mm, 150 mm in from the inner edge.
Does a stair need handrails on both sides?
It depends on the country. In Norway (TEK17 § 12-14) every stair has handrails on both sides – the railing’s top counts as one –, and a stair shared by several homes two on each side, at 0.9 m and 0.7 m. Sweden asks for both unless one is enough, Finland for both along the whole flight, Ireland for both on a stair wider than 1 m. Elsewhere the app draws one unless you choose both. It puts them where your country asks, and the check says when a side is missing.