Metalwork · Railings
Metal railing calculator
A 3 m run, 1 m high, with posts and handrail in 40 × 40 × 2 square tube and 12 mm square bar balusters at a gap of 100 mm at most, takes 24 balusters in 2 bays: 29.64 m of steel weighing about 44.5 kg. Change the sizes and the profiles: the calculator spaces the balusters evenly, gives the cut list and opens it in the bar optimizer.
Cut list
| Profile | Piece | Length (mm) | Qty |
|---|
What the codes say
This page does not know the code where you build: type the largest gap and the height it asks for. As an example of what one code says, Spain's CTE DB SUA (SUA 1, section 3.2) asks for a barrier at least 0.90 m high where the drop is up to 6 m and 1.10 m beyond, measured from the floor or, on a stair, from the pitch line; and, in dwellings, nursery schools and the public areas of shops and public venues, no opening a 10 cm sphere can pass through (15 cm in the public areas of other buildings). Check the code in your country.
How it is worked out
For the run above: (3000 − 40) / 1500 gives 2 bays and 3 posts, and each bay is (3000 − 3 × 40) / 2 = 1440 mm clear. 12 mm balusters at 100 mm at most: ⌈(1440 − 100) / 112⌉ = 12 per bay, at (1440 − 12 × 12) / 13 = 99.7 mm. Each baluster is 1000 − 40 − 50 − 40 = 870 mm. The 40 × 40 × 2 tube is 1600 − 36² = 304 mm², 304 × 7850 / 10⁶ = 2.386 kg/m; the 12 mm bar is 144 mm², 1.130 kg/m. Weight: 8.76 m × 2.386 + 20.88 m × 1.130 = 44.5 kg. The sections are sharp-cornered, as in the metal weight calculator: a rolled tube with round corners weighs a few per cent less.
What this page does not do
- It does not check the strength. The horizontal load the railing must take and its fixing are for whoever signs the job.
- It does not count base plates, anchors, welding or paint.
- It is a straight, level run. On a stair the balusters stand on the pitch and each one is a different length.
Questions people ask
- How many balusters does a railing need?
- Divide each bay's clear width minus the largest gap by the baluster width plus the gap, and round up: a 3 m run in 2 bays of 1440 mm with 12 mm balusters at 100 mm at most needs 12 per bay, 24 in all, at 99.7 mm.
- How far apart should balusters be?
- As far as the code where you build allows, no more: Spain's CTE DB SUA 1 (3.2.3) allows no opening a 10 cm sphere passes in dwellings. Check the code in your country and type its figure as the largest gap.
- How much does a steel railing weigh?
- The 3 m run above, in 40 × 40 × 2 tube with 12 mm square balusters, weighs about 44.5 kg, 14.8 kg per metre of run.