A kicker in construction is a short, step-like block of concrete (or a timber/steel brace) that anchors the base of a wall, column, or formwork to keep it properly aligned during building. The term shows up in two main contexts: concrete work and timber framing. In both cases, the kicker’s job is the same: provide a stable reference point so the structure above it stays exactly where it’s supposed to be.
Concrete Kickers (Column Starters)
The most common use of “kicker” in construction refers to a small concrete step, typically 50 to 150 mm (2 to 6 inches) tall, poured at the base of a wall or column. These are also called column starters or starter blocks. When you’re casting a column or wall on a flat surface like a floor slab or footing, it’s difficult to keep the formwork panels locked in place during the pour. The wet concrete pushes outward at the bottom, and without something to brace against, the forms can shift or blow out. A kicker solves this by giving the formwork a solid ledge to sit against.
The kicker is poured first as part of the slab or footing, then allowed to set. Once it’s cured, the formwork for the full wall or column is erected around it, with the kicker acting as both an anchor and a guide. This provides the construction team with a precise reference point, ensuring the column or wall starts in exactly the right position. Without a kicker, even small misalignments at the base can compound as the structure rises, leading to walls that are out of plumb or columns that don’t line up with the structural grid above.
Kickers also help seal the joint between the slab and the wall. Because the kicker is poured monolithically with the slab (as one continuous pour), there’s no cold joint at the very bottom where water could seep through. The cold joint moves up to the top of the kicker instead, where it’s easier to manage and less vulnerable to hydrostatic pressure.
How Concrete Kickers Are Built
A concrete kicker is formed using small timber or plywood boxes set into the slab formwork before the slab pour. The reinforcement bars (rebar) for the future wall or column extend up through the kicker, creating a continuous structural connection. After the slab and kicker are poured together, the small box forms are stripped, leaving a raised concrete block with rebar sticking out of it.
Getting the kicker positioned accurately matters more than you might expect. Construction teams typically snap chalk lines on the slab formwork to mark the exact footprint of the kicker before placing the box forms. If the kicker is even slightly off, the entire wall or column above it will be off too, which is much harder to fix after the fact. On large commercial projects, kicker positions are surveyed and checked before the slab pour begins.
The concrete mix for the kicker matches the slab it’s poured with. No special materials are needed. The key requirement is that the kicker surface is clean and roughened before the wall pour begins, so the new concrete bonds well to the old.
Advantages and Drawbacks
Kickers significantly reduce casting errors. They make formwork installation faster because the panels have a defined edge to butt against rather than relying entirely on bracing and ties to hold position on a flat surface. For walls in particular, kickers eliminate the common problem of concrete leaking out under the base of the form during a pour.
The main drawback is that kickers create a construction joint, which is a potential weak point if not executed properly. If the kicker surface isn’t cleaned or prepped before the wall pour, the bond between old and new concrete can be poor. In water-retaining structures like basements or tanks, this joint needs careful detailing, often with a waterstop embedded in the concrete, to prevent leaks. Some contractors and engineers prefer to skip the kicker entirely on certain projects, instead using proprietary clamping systems that grip the slab edge directly. This eliminates the extra joint but requires more robust temporary bracing.
Kickers in Timber Framing and Roofing
In wood-frame construction, a kicker is a diagonal brace that transfers lateral loads between two structural members. You’ll see kickers used most often where roof trusses or joists meet exterior walls, particularly at parapet walls that extend above the roofline. The kicker runs at an angle from the top of the wall down to the roof structure (or vice versa), preventing the wall from being pushed outward by wind or the weight of the roof.
These kickers are typically cut from 2×4 lumber and nailed or screwed into place. In commercial light-frame construction, kicker braces at parapet walls are a standard detail for shear transfer, meaning they help move wind and seismic forces from the wall into the roof diaphragm where those forces can be distributed safely. Without them, tall parapet walls would be vulnerable to blowing over in high winds.
Kicker Plates in Formwork Hardware
You may also hear “kicker” used to describe a 2×4 plate nailed to the base of concrete formwork as a positioning guide. Forming accessory systems from manufacturers like Dayton Superior use kicker plates in combination with snap brackets, which are heavy-gauge galvanized steel clips that attach to the formwork panels. The kicker plate sits at the base, and the bracket locks the panel against it, providing both alignment and resistance to the outward pressure of wet concrete. This is essentially a mechanical version of the poured concrete kicker, serving the same purpose with removable hardware instead of a permanent concrete step.
Regardless of the specific application, every type of kicker in construction serves the same fundamental role: it holds something in place at its base so the structure above can be built accurately and safely.