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Building components · Concrete & Reinforcement

Kicker

Explains the kicker as a position that fixes the line of the element above, and separates it from the projecting reinforcement it is commonly confused with.

Form:Connector or supportRoles:TerminationStructure

Educational reference entry. What this element has to do, and whether any particular arrangement of it is adequate, depends on the whole assembly, the loading, the exposure, local requirements, the manufacturer's instructions and qualified professional design.

Overview

What a kicker is

When a wall or column is cast on top of a slab or base, the formwork for it has to start somewhere and has to start in the right place. A kicker is a short upstand of concrete, cast as part of the slab or base beneath, standing in the line of the element above. The formwork for that element is then set against the kicker rather than against a flat slab surface.

Its purpose is positional. It fixes the line of the wall or column while the earlier pour is being cast, when setting out is easiest to control, and it gives the formwork above something to sit against and be sealed to. That is also why a kicker is not merely a convenience: an out-of-line kicker puts the element above out of line, and a kicker that leaks at its junction with the formwork leaves the base of the wall poorly formed exactly where it meets the pour below.

Boundaries

How it differs from nearby elements

The distinctions that keep this entry from being a restatement of its neighbours.

  • It is not a starter bar. The kicker is concrete that locates formwork; the starter is reinforcement that continues the steel into the next pour. They occur at the same place and in the same operation, which is why they are confused, but one positions the mould and the other carries force, and an element may have starters with no kicker at all.
  • It is not an upstand in the weathering sense. That upstand carries a waterproofing or roofing layer up above a surface; a kicker's job is setting out, and it is normally buried by the element cast on top of it.
  • It is not a separate element added to the slab. A kicker cast monolithically with the pour beneath is part of that pour, and one cast afterwards introduces a further joint plane — which is precisely why how it was formed matters.

Terminology

Common names and aliases

These names describe the same element. The library keeps one entry per component so that a trade term or a regional name never becomes a second, thinner page.

  • stub
  • upstand kicker

Dependencies

What it depends on

What has to be right elsewhere for this element to do its job.

  • Being set out accurately, because the element above inherits its line and correcting that later means moving formwork or moving the wall.
  • Being cast so that its own concrete is sound at the junction, since it sits at the base of the wall and forms part of the joint plane between the pours.
  • The seal between it and the formwork above, as fluid concrete finds any gap at the base of a pour.
  • The reinforcement passing through it, since a kicker occupies exactly the congested region where starters and wall steel come together.

Considerations

Topics that genuinely apply here

Subjects worth discussing about this element. These are discussion topics, never measured values, ratings or performance claims.

Tolerance & fit

Setting out is the kicker's whole reason for existing, and any error in it is transferred directly to the element above and is expensive to correct once cast.

Buildability

The face of the kicker is where the formwork above is closed. A rough, damaged or out-of-plumb kicker face makes that closure difficult exactly where it needs to be tight.

Moisture

In an element relied on to resist water, the kicker sits at the joint plane between base and wall, so how it is formed is part of how that joint performs rather than a separate matter.

Structural transfer

The kicker is not the mechanism of continuity between the pours; reinforcement crossing the plane is. Treating the upstand itself as the structural connection misreads what it does.

Materials

Commonly formed from

Material families this element is commonly realised in. This states common practice only — it is not a statement that any of these materials suits this component in a particular building, which depends on the whole assembly and on qualified review.

Materials LibraryReady-mixed concrete →The upstand is cast from the same concrete as the pour it belongs to, which is part of why casting it monolithically is significant.Materials LibraryReinforced concrete →Where reinforcement passes through the upstand into the element above, the kicker is part of a reinforced member rather than a plain block of concrete.

Assemblies

Building systems this element is met in

The role this component fills inside each assembly. A role describes what the element does there — it is not a statement that this component suits that system in any particular building.

Edge and terminationConcrete Frame →Columns and walls cast off a floor are commonly located by an upstand formed with that floor.Edge and terminationJointing and sealingBasement Structure →The base-to-wall junction is both the set-out point for the wall and a joint that has a water-resistance duty.Jointing and sealingIntegral Water-Resisting Structure →Where the concrete is the water resistance, what happens at the base-of-wall joint is part of the system rather than incidental to it.Edge and terminationCantilever Retaining Wall →The stem is set out from the base pour, and the upstand is where that set-out is held.Edge and terminationRaft Foundation →Walls rising off a raft are located from it, and the upstand records that line before the raft is finished.

Clarifications

Commonly misunderstood

  • That a kicker is optional tidy-up. Where it is used, it is the physical record of the set-out of the element above, made at the moment that set-out was easiest to establish.
  • That kicker and starter bars are the same arrangement under two names. One is concrete for position, the other is steel for continuity, and each can exist without the other.

Conversations

Questions for qualified professionals

Questions worth asking someone with the project in front of them. This page cannot answer them.

  • Was the kicker cast with the pour beneath or separately, and what does that mean for the joint at this location?
  • How was the set-out of the kicker established and checked before the concrete was placed?
  • How is the formwork above sealed against the kicker at the base of the pour?
  • If this element resists water, how is the joint at the kicker addressed in the design?

Go deeper

Related Build Design Hub guides

Planning guidance behind the decisions this element involves.

Preparation

Related planning checklists

Owner-side preparation before the conversation where this element comes up.

What this entry does not do

  • This entry describes a position. It states no kicker height, no dimension, no tolerance and no method of construction, and no such value can be inferred from anything written here.
  • Whether a kicker is used, how it is formed and what it has to achieve at a particular junction are matters for the designer and the temporary works designer for that structure.

Concrete & Reinforcement Elements

The positions that govern how concrete is placed, joined and reinforced — the joints between pours, the zones around reinforcement, and the faces that form the finished surface.

Browse all concrete & reinforcement entries →