Shuttering calculation for footing

How To Calculate Shuttering Quantity For Footing

In this post, I’ll show you an easy process of shuttering calculation for footing.

Depending on the site condition of a building project we sometimes need to make concrete forms for RCC footings.

Sometimes, we make brick walls all around the footing that works as a form. In that case, you don’t need to calculate shuttering materials.

But if you need to make concrete forms with shuttering materials then it’s wise to use wooden shuttering materials as it’s cheap and widely available.

I’ll show you a step-by-step process of shuttering calculation for footing.

At the end of this post, I’ll also show you the thumb rules for calculating shuttering materials for footings.

So, let’s learn the process of…

Shuttering Calculation For Footing

In your building construction project, you must have drawing sheets for footings like this:

Footing Layout

This is an example of a footing layout.

With that…

Step-1: Summarize Similar Type Of Footings

A building can have different sizes of footings. The size of all the footings isn’t the same.

You need to count the same type of footings together.

In our example drawing, we have:

  • F1 = 4
  • F2 = 4
  • F3 = 1

If you want to construct them all at once you need shutters for all the footings.

But if you want to save money on shuttering materials you can build some footings at the first attempt. Then reuse the forms on other footings.

For example, we have 4 numbers of F1 footing. At the first attempt, you can cast two footings and reuse the forms on the rest two footings later.

Step-2: Calculate Sheathing Materials

Let’s calculate the sheathing materials for footing (F1).

For that,

First, get the size of the footing from your structural drawing book.

Let’s say the size of our example footing is, 5′-0″ × 4′-0″ × 1′-0″.

With The sheathing the footing will look like this:

Sheathing around footing.

Next, get the length of the sheathing.

The formula is,

= 2 × (Length + Width)

= 2 × (5′ + 4′-4″)

= 18′-8 feet.

After that, Calculate the area of sheathing materials.

The formula is,

= Length of sheathing× Thickness of footing

Calculating the height of sheathing panels of a footing.

= 18′-8″ × 1′-0″

= 18.67 Square feet.

As we have 4 numbers of F1 footing. So the required sheathing materials are,

= 4 × 18.67

= 74.68 square feet.

1″ thick plywood or lumber are normally used as sheathing materials.

Generally, Plywood is available in the market as 4′ × 8′ panel. And the area of 1 piece of plywood is 32 square feet.

So the required number of plywood for our F1 footings –

= 74.68 ÷ 32

= 2.33 nos.

But if you want to use lumber instead of plywood then you need to get the quantity as cubic feet. Because lumbers are normally sold as cubic feet in the market.

So the required lumber is,

= area of sheathing × Thickness of lumber

= 74.68 × 1″

= 6.20 cubic feet (1″ = 0.083′)

Step-3: Calculate Required Cleats

Generally, 2″ × 2″ or 2″ × 3″ lumber are used as cleats for wooden forms of footings.

Cleats in footing's form

Cleats are normally fixed at 2 feet center to center.

First, calculate the periphery of the footing.

The formula is,

= 2 × (Length + width)

= 2 × (5′ + 4′)

= 18 feet.

Isolated footing

Next, calculate the required number of cleats.

The formula is,

= Periphery of the footing ÷ Center to center distance of cleats.

= 18′ ÷ 2′

= 9 nos.

Finally, calculate the total length of cleats.

And the formula is,

= number of cleats × length of a cleat

= 9 × 1′ [The length of a cleat is equal to the thickness of the footing.]

= 9 feet.

This is for one number of F1 footing.

But we have 4 footings in our example project.

So, the total required cleats for all the F1 footings are,

= 4 × 9

= 36 Running feet.

[Note: Footings that are less than 1 foot deep and 2 feet square, forms can be build of 1-inch sheathing without cleats. In that case, you don’t need to calculate lumber for cleats.]

Step-4: Calculate Lumber For Stakes

Stakes are used for footings that are larger than 4 feet square.

Stakes in footing's form

You can use 2″ × 2″ lumber for this purpose at 2 feet center to center distance.

For that…

First, calculate the periphery of the footing.

The formula is,

= 2 × (Length + width)

= 2 × (5′ + 4′)

= 18 feet.

Next, calculate the required number of stakes.

The formula is,

= Periphery of the footing ÷ Center to center distance of stakes.

= 18′ ÷ 2′

= 9 nos.

Finally, calculate the total length of stakes.

And the formula is,

= number of stakes × length of a stakes

= 9 × 1′ [1-foot length for a stake is enough.]

= 9 feet.

This is for one number of F1 footing.

But we have 4 footings in our example project.

So, the total required stakes for all the F1 footings are,

= 4 × 9

= 36 Running feet.

Step-5: Calculate Tie Brace

Tie brace also recommended across the top of the form for larger footing to prevent spreading.

Tie brace in footing's form

First, Calculate the required number of tie brace.

Tie brace is normally used at 4 feet center to center, either across the length or the width of the footing.

As the length of our F1 footing is 5 feet, we need just 1 tie brace.

Next, calculate the length of the tie brace

The tie brace is normally extended 4″ at both ends of the footing.

The tie brace is extended at both ends beyond sheathing panels

If we use the tie brace along the long side of our footing, the length will be,

= 5′ + 4″ + 4″

= 5′-8″

Finally, calculate the quantity of tie brace.

Normally, 1″ × 6″ lumber is used for this purpose.

So the quantity is,

= 1″ × 6″ × 5′-8″

= 0.236 cubic feet.

As we have 4 numbers of F1 footing, the total required lumber for tie brace is,

= 4 × 0.236

= 0.944 cubic feet.

So, the summary of the required shuttering materials for all of our F1 footings:

  • 1″ thick plywood – 2.33 nos, or 1″ thick lumber – 6.20 cubic feet
  • 2″ × 2″ lumber (for cleats and stakes) – 72 Running feet
  • 1″ × 6″ lumber (for tie brace) – 0.944 cubic feet

This is the general process of calculating shuttering materials for footing.

But you can also apply…

Thumb Rules For Shuttering Calculation For Footing

Thumb rules are some heuristic guidelines that provide some basic rule-set to calculate shuttering materials for footing.

They are formed using previous projects’ data.

Let’s see how we can use thumb rules.

First, calculate the shuttering contact area.

The formula is,

= 2 × (L + B) × H

3d isolated footing with dimensions

For one F1 footing,

= 2 × (5′ + 4′) × 1

= 18 Square feet.

As we have 4 numbers of F1 footing, so the contact area is,

= 4 × 18

= 72 square feet.

Next, calculate sheathing materials

The formula is,

= Contact area × Thumb rule

If you want to use plywood then the required number of plywood is,

= 72 × 0.03

= 2.16 nos

If you want to use 1″ thick lumber instead of plywood then the required lumber is,

= 72 × 0.08

= 5.76 cubic feet.

Next, calculate 2″ × 2″ lumber for cleats and stakes

Again, the formula is,

= Contact area × Thumb rule

= 72 × 0.9

= 65 running feet.

Similarly, calculate 1″ × 6″ lumber for tie brace.

= 72 × 0.01

= 0.72 cubic feet.

Finally, calculate nails for shuttering.

= 72 × 0.02

= 1.44 kilograms.

That means, the thumb rules for calculating shuttering materials for footings are:

  • 4′ × 8′ × 1″ plywood – 0.03 nos/sq.ft.
  • 1″ thick lumber – 0.08 cubic feet/sq.ft.
  • 2″ × 2″ lumber – 0.9 running feet/sq.ft.
  • 1″ × 6″ lumber – 0.01 cubic feet/sq.ft.
  • Nail – 0.02 kg/sq.ft.

Conclusion

The required shuttering materials for footing are totally dependent on the earth status of the project.

For example, if the excavated earth is firm enough to withstand against concrete’s load, we normally pour concrete into footings without any forms.

Sometimes, we construct a 3″ thick cement concrete platform below the footing and make brick walls all around the footing which work as a form for footing.

We sometimes make wooden forms above cement concrete platforms instead of brick walls depending on the earth’s condition.

In that case, you can’t use stakes. You need to fix 1″ × 2″ lumber on cement concrete platform all around the form.

So, before calculating shuttering materials for footing inspect the earth condition of your project.

Your Turn:

I found that people use different thumb rules for calculating shuttering for footing.

Which thumb rules do you use for this purpose?

Please share your opinion in the comments below…

1 thought on “How To Calculate Shuttering Quantity For Footing”

  1. At least now the information is widely available.Just think 5 -10 years ago this would not be possible.
    Thanks for sharing the info.
    Michel Rezé

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