Planning and Design, Spiral Staircases

SPIRAL STAIRCASES, PLANNING AND DESIGN

With many years' experience, we are happy to help you with guidance and advice during planning and design. On ordering, each spiral staircase is drawn up specially and the drawing is sent to the customer for approval prior to manufacturing.


Staircase radius

The staircase radius is the dimension from the staircase's centre to the outer edge of the handrail. Weland manufactures spiral staircases with a radius of 600 to 1500 mm.


Rise

The rise should be chosen based on the given height between the landings. A suitable radius and the number of steps per revolution then determine the step rise.

The step rise should be between 160 and 220 mm. The lower the rise you choose, the deeper the step needs to be. The normal rise is about 170 to 180 mm.

The formula for the rise is 2 x h + W = 580-640.


Right or left curved staircases

Weland spiral staircases are manufactured curved to the right or the left. Right curved staircase means that it curves to the right while ascending (centre tube to the right while ascending).


Headroom

The headroom on the stairs must not be less than 2000 mm. The height is measured between two points located directly below each other.

Measure from the top edge of the lower step’s nose to the lower edge of the level’s (step) rear edge.


Number of steps per revolution

The step template on the right helps you plan the staircase solution and to determine the number of steps per revolution. The table below shows the tread depth along the path line for each radius and suitable riser heights.

Fields marked (green) in the table are the staircase dimensions that should be aimed for during the planning stage.

Radius steps/revolution Tread depth along path* Suitable riser
600/14 157 200-220
600/15 147 200-220
600/16 137 200-220
700/15 188 200-220
700/16 177 200-220
700/17 166 200-220
700/18 157 200-220
800/16 216 180-210
800/17 203 180-210
800/18 192 190-220
800/19 182 190-220
800/20 173 190-220
900/16 255 175-200
900/17 240 175-200
900/18 227 175-200
900/19 215 180-210
900/20 204 180-210
900/21 194 180-210
1000/16 294 165-185
1000/17 277 165-185
1000/18 262 165-185
1000/19 248 175-200
1000/20 236 175-200
1000/21 224 180-210
1000/22 214 180-210
1000/23 205 180-210
1100/18 297 165-180
1100/19 281 165-180
1100/20 267 165-190
1100/21 254 170-200
1100/22 243 170-200
1100/24 232 170-200
1100/25 222 170-200
1200/17 351 155-190
1200/18 331 155-190
1200/19 314 155-190
1200/20 298 155-190
1200/21 284 155-190
1200/22 271 160-200
1200/23 259 170-200
1200/24 249 170-200
1300/18 366 155-180
1300/19 347 155-180
1300/20 330 155-180
1300/21 314 155-180
1300/22 300 155-190
1300/23 287 155-190
1300/24 275 155-190
1400/20 361 155-180
1400/21 344 155-180
1400/22 328 155-190
1400/23 314 155-190
1400/24 301 155-190
1400/25 289 155-190
1400/26 278 155-190
1500/22 357 150-180
1500/23 341 150-180
1500/24 327 150-180
1500/25 314 155-180
1500/26 302 155-180
1500/27 291 155-180
1500/28 280 155-180

Childproof

Childproof means that none of the openings in the staircase are permitted to be larger than 100 mm up to a railing height of 800 mm.


Handrail

As standard handrails are made of stainless steel tube, Ø 42 mm. For wood handrails, the handrail is ø 50 mm as standard.


Height, railing

The height of the railing is 1100 mm at the nose of the step. Extra handrails are placed at an optional height inside the balusters, for example, 900 mm. The railing height of the landing is 1100 mm as standard.


Load, railing

The railing is dimensioned to withstand a load of 1.0 kN/m handrail.


Load on tread

The stair treads are dimensioned for a distributed load of 5.0 kN/m² or a point load of 5.0 kN.


Distance to wall

The spiral staircase's external radius must be at least 50 mm from walls. The tread depth is calculated along an imaginary path 250 mm from the radius.


Stays

The spiral staircase must be fitted with stays every revolution (2.5 to 3 metres in height). This can be done using the square landing fixing. If the stairs have no square landing on each revolution, bracing must be fitted between the step and wall using custom stays.

When the spiral staircase cannot be braced to an adjacent wall, it needs to be stabilised using a vertical stay. These are attached at the bottom against the completed floor or foundation.


Attachment of landings

Use suitable type of screw taking into consideration the materials at the attachment points.


Attachment base plate

Use suitable type of screw taking into consideration the material at the attachment point.

A base must be cast to fasten spiral staircases when there is no existing platform. Wind strengths, etc. must be taken into consideration when designing this.

Generally, the distance to the base plate from the wall must be at least the stair’s radius plus 50 mm.