Spiral staircase designer

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Stair Parameters

Stair Type

Spiral

Room

Room length

6500 мм

Room width

6500 мм

Floor height

2800 мм

Floor slab thickness

200 мм

Opening

Opening diameter 2700 мм

Spiral staircase

Stair diameter 2600 мм

Direction

Staircase

Tread thickness

40 мм

Tread overhang

30 мм

Railings

Railing height 1000 мм

Handrail width 70 мм

Baluster width 40 мм

Baluster spacing 130 мм

Post width 80 мм

Materials

Treads

Risers

Stringers

Calculation Results

Step count17

Riser height 176.5 mm

Tread depth 280.9 mm

Stair angle32°

Headroom 2038 mm

Blondel formula 634 mm

Wood volume 0.849 m³

Weight (approx.) 637 kg

Material cost (approx.) 1561 $

Standards Check

✓ Riser height: 176mm (150–200)

✓ Tread depth: 281mm (250–300)

✓ Blondel formula (2h+g): 634mm (600–640)

✓ Stair angle: 32° (30–39)

✓ Headroom clearance: 2038mm (min 2000)

✓ Stair width: 1160mm (min 800)

✓ Railing height: 1000mm (min 900)

✓ Baluster spacing: 130mm (max 150)

✓ Winder inner depth: 113mm (min 100)

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