HOW TO CALCULATE STAIRCASE SHUTTERING

 

HOW TO CALCULATE STAIRCASE SHUTTERING

Calculating staircase shuttering is easy process, estimating the surface area of all the parts of the staircase that need formwork (shuttering), including:

1. Tread :- The part of the step on which we keep our feet. It is the top portion of the step. The ideal width of a tread is such that it can accommodate all the feet sizes. The general tread size is 250-300 mm.
2.  Riser :- A riser gives the height to each step. It is the rising part of the step. Or in other words, the riser is the vertical distance between two treads. The general size of the riser is 150-200 mm.
3. Waist slab :- The bottom portion of the flight that supports the steps. The thickness is 150-200 mm.
4. Landing :- The horizontal part of the staircase on which a flight starts or ends. It is the resting place. Landings are used to change the direction of the stairs.
5. Side supports and soffits :- The plan area of the waist slab of the staircase is called horizontal projection. It is also called “going of flight”. It is equal to the horizontal distance between the first and last riser.

---

🔧 Step-by-Step Staircase Shuttering Calculation

Assume a typical RCC staircase with:

• Number of steps = n
  
• Tread (step depth) = T
• Riser (step height) = R
• Stair width = W
• Waist slab thickness = t
• Landing dimensions = L x W
• Total horizontal run = n × T
• Total vertical rise = n × R

---

v  Formulas to Use

1. Tread Surface Area (Top of steps)

Tread Area= n × T × W

2. Riser Surface Area (Front face of steps)

Riser Area= n × R × W

3. Waist Slab Shuttering Area (Bottom inclined part)

Use Pythagoras to calculate inclined length:

Inclined Length=  √ (Run²+Rise²)

Waist Slab Area = Inclined Length × W

4. Landing Bottom Area (if any)

Landing Area = L × W

5. Side Shuttering (if formwork is also applied to vertical edges)

Optional – depends on your site requirements.

---

📘 Example Calculation

Let’s take a staircase with:

• Steps = 10
• Tread = 250 mm (0.25 m)
• Riser = 150 mm (0.15 m)
• Width = 1 m
• Waist thickness = 150 mm (for structure, not for shuttering)
• Landing = 1.2 m × 1 m

👉 Tread Area:

10×0.25×1=2.5 m²

👉 Riser Area:

10×0.15×1=1.5 m²

👉 Waist Slab Inclined Length:

Run = 2.5m, Rise = 1.5m

Inclined Length = √(2.5² + 1.5²)

Waist Slab Area = 2.915 x 1 = 2.915m²

 

 

👉 Landing Area:

1.2×1=1.2 m²

---

✅ Total Shuttering Area

Tread+Riser+WaistSlab+Landing = 2.5+1.5+2.915+1.2 = 8.115 m²

---

📌 Tips:

• Add 5–10% extra for wastage and joints.
• Include side formwork if visible edges are to be shuttered.