In building construction, especially during the casting of reinforced concrete columns, a small but crucial element is often added at the bottom of the column formwork. This component is known as a kicker. While it may look minor, the kicker plays an essential role in the accuracy and strength of the column. In this blog, we’ll explore what a column kicker is, its purpose, how it is made, and why it is important in construction work.
What is a Kicker?
A kicker, also called a starter or column stump, is a small portion of concrete – usually 50mm to 150mm in height – cast above the footing or slab level at the base of a column. It is formed during the casting of the foundation or slab to act as a guide for the column shuttering (formwork) later.
The kicker helps maintain the correct alignment and positioning of the column formwork, especially in verticality and dimensions. It ensures that the formwork for the column is correctly anchored and doesn’t move during concreting.
Why is a Kicker Important?
Even though it may look like a tiny projection, the kicker serves several important purposes in construction:
1. Accuracy in Formwork Placement
The kicker provides a physical boundary that helps carpenters align the column shuttering perfectly with the structural layout. Without a kicker, the base of the column formwork may shift during pouring, affecting the plumb and location of the column.
2. Leakage Prevention
During concreting, there’s a chance of slurry leakage at the junction of slab and column. A properly cast kicker reduces this risk by acting as a seal between the two layers.
3. Level Reference
The kicker acts as a level reference line for future stages of work. It marks the start point of the column and confirms that the column will rise from the correct height and position.
4. Improved Structural Bonding
Casting a kicker at the same time as the footing or slab provides a monolithic bond between the kicker and the base. This strengthens the connection and reduces the chances of cold joints or weak interfaces.
How is a Kicker Constructed?
The kicker is usually cast during the concreting of the footing or slab. Here’s a simple step-by-step process:
- Formwork is fixed for the slab or footing with appropriate alignment and reinforcement.
- Reinforcement bars for the column are positioned with enough projection above the base level.
- After concrete is poured for the slab or footing, a small height (usually 50mm to 150mm) is left for the kicker by extending formwork accordingly.
- Once concrete is poured and levelled up to kicker height, it is left to cure.
- After hardening, this kicker acts as a firm base to fix column shuttering later.
Kicker Dimensions
- Height: Typically ranges from 50 mm to 150 mm
- Width: Same as the column cross-section
- Material: Same grade of concrete as footing/slab, usually M20 or higher depending on design
Mistakes to Avoid While Casting a Kicker
- Poor alignment – If the kicker is not straight or correctly positioned, the entire column will be off-centre.
- Uneven surface – A bumpy or unlevel kicker makes it hard to fix shuttering later.
- Incorrect height – If the kicker is too high or too low, it may interfere with the formwork or the next construction level.
- Improper curing – Like any concrete element, the kicker needs curing for strength and durability.
Kicker vs No Kicker – Which is Better?
Some construction teams skip the kicker to save time. While it may work in small residential projects, skipping a kicker in large or high-rise buildings is not advisable. Without a kicker:
- Column may become misaligned
- Concrete slurry leakage may increase
- Rework may be needed, wasting time and money
Therefore, including a kicker is considered best practice in professional site work.
Where Else Are Kickers Used?
Apart from columns, kickers are sometimes used at the base of shear walls, lift cores, or retaining walls to help align and stabilise vertical formwork. The same principle applies – a small starter element helps guide the full structural element that will be cast above it.
Advantages of Using a Kicker
Precise alignment of column formwork
Time-saving during shuttering fixing
Improved concrete joint between slab and column
Reduces formwork movement during vibration
Minimises concrete leakage at joint
Acts as a physical template for carpenters
Disadvantages of a Kicker
Extra labour and time required during slab or footing casting
If not done properly, misalignment of kicker can lead to wrong column position
Needs proper curing, or it may crack and affect column base
In low-budget or small projects, it may be considered non-essential
IS Code Reference
Though there’s no separate IS code exclusively for kickers, related guidance is found in:
- IS 456:2000 – General concrete construction practices
- SP 34 – Detailing of reinforcement, including starter bars
- IS 3370 – For watertightness, which is related to kicker leakage concerns in tanks or basements
Conclusion
In construction, small details often make a big difference – and a kicker is one such detail. While it’s just a small projection of concrete at the start of a column, it ensures proper alignment, prevents leakage, and strengthens the connection between the column and the base. Whether you’re a civil engineer, supervisor, or site mason, never underestimate the value of a well-cast kicker. It sets the tone – and alignment – for the entire column above.
FAQs on Column Kickers
Q1. Is a kicker necessary in every column?
A kicker is not mandatory for all small-scale projects, but it is strongly recommended for large or multi-storey constructions to ensure accuracy and alignment.
Q2. Can a kicker be cast separately after slab concreting?
It can be, but it’s not advisable. For best strength and bond, a kicker should be cast monolithically with the base slab or footing.
Q3. What if the kicker is out of alignment?
You may need to break and recast the kicker or adjust shuttering manually. It can cause delays and extra work.
Q4. Can I use bricks or mortar as a kicker?
No. Kickers should be made of reinforced concrete with the same mix as the base to ensure uniform strength and bonding.
Q5. What happens if I skip the kicker?
Your column formwork may shift during concreting, leading to crooked columns or dimensional errors.