Guide
Stair rules for homes in Norway, Sweden, Denmark and Germany compared
Riser, going, width, headroom, guards and the stairwell opening for a stair inside a house under TEK17, Boverket, BR18 and DIN 18065, side by side, with a worked example.
Calculators
Stair calculator:steps, stairwell opening and spiral stairs
Type in the height from floor to floor, and see how many steps you need, how long the hole in the floor above must be, and whether the stair meets your country’s rule for a stair inside a home. Pick spiral stair for one round a column.
How it is counted
A stair inside a home is checked against TGD K (pre-accepted values: another solution can be documented).
An example
From floor to floor 2,700 mm: 15 risers of 180 mm with a going of 260 mm make 2 × riser + going 620 mm, under TGD K. Under a floor 300 mm thick, the stairwell opening must be 3.32 m long for 2 m of headroom.
Questions and answers
What is the step rule 2 × riser + going?
A stair is comfortable when two risers and one going add up to about one stride, 600–640 mm. Norway’s pre-accepted values under TEK17 § 12-14 ask for that range and a going of at least 250 mm; Germany’s DIN 18065 asks for 590–650 mm.
How many steps does my stair need?
Divide the height from floor to floor by a comfortable riser of about 170–190 mm. The calculator picks the number that brings 2 × riser + going closest to the middle of your country’s range; you can set it yourself.
What about winders, spiral and loft stairs?
The calculator checks a straight flight and a spiral stair round a column. In House Madness you can draw stairs with turns, winders, landings and spiral stairs, and each is checked as drawn, with the headroom under the roof.
How long does the stairwell opening need to be?
Long enough that the floor above stays at least the headroom over the steps, measured straight up from the nosings: (headroom + floor thickness) × going ÷ riser, back from the top riser. With 2.0 m of headroom, a 300 mm floor, 180 mm risers and a 260 mm going that is 3.3 m. Its width is the stair’s, plus the linings round it. A spiral stair sits in a square opening about 100 mm larger than its diameter.
How big does a spiral stair need to be?
Its going and the step rule are measured on the walking line, midway between the column and the rim, and its usable width from the column to the rim. Norway asks for 0.8 m in a home and 0.1 m more for a stair that isn’t straight, which takes a diameter of about 1.9 m; ready-made spirals of 1.2–1.6 m are narrower than that. Pick your country above to check against its rule.
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Draw the whole house, free
House Madness counts every room this way as you draw, in 3D, and prints the drawings for the application.