By Joe Kirkwood and Holly Kirkwood
Rebar or bar support is a term used to describe products that elevate rebar in reinforced concrete. When concrete is poured for bridges, roads, runways, foundations, caissons, etc., rebar and bar supports are required to strengthen the structure and to provide additional support. Rebar is needed to when pouring big slabs of concrete to reinforce the strength of the concrete and to help reduce cracking. Rebar aids in absorbing and distributing tension caused when concrete expands and contracts due to climate variations (hunker.com). In order to have rebar in a concrete pour, contractors also need rebar support. The type of rebar or mesh support used depends on the type of surface underneath the concrete, the structural elements and the design of the project.
There are several types of rebar support used depending on the needs of the project. The CRSI (Concrete Reinforcing Steel Institute) has implemented standards for such products. At Outpost, we have found Dayton Superior to be our company of choice when it comes to complying with these standards. And of course, they get bonus points for being the industry standard of products Made in America. Below we break down the different types and styles of rebar or bar support and their uses.
CS - CONTINUOUS SUPPORT (aka Zig-Zags)
Continuous support is a continuous, vertical steel spacer for thick and heavy concrete applications. The support provided is stable and because of its weight, will not slide or tip. Zig Zags typically sit in the middle of the concrete. Because of its design, it can be bent around partitions and continue to hold its load-bearing capacity.
Specs:
• Height covers 2” to 16”
• Available in plain black or epoxy coating (prevents rust)
• Uses: In deep and thick concrete pours such as highways, runways, and taxiways
Castle Chair
Castle Chairs are used to maintain the elevation of rebar in reinforced concrete. The chair is cone shaped with rebar saddles and a wide base. The wide base prevents it from sinking into the dirt or base below it. The rebar intersections where the rebar ties together are what sit on top or in the rebar saddles. Castle Chairs keep the rebar off sub-straight and in its specified, engineered position.
Specs:
• Cover height 1-1/2” to 6-1/4” in ¼” increments (Dayton Superior)
• Plastic footing to keep from corroding
• Available in epoxy coated or plain
• Uses: Any concrete pour, interior slabs, driveways, etc.
SNAP-ON MESH CHAIR
Snap-On Mesh Chairs are used for high heat resistance and high strength applications and are mostly used with mesh sheets as opposed to rebar. They can support 8’ x 20’ sheets or smaller on grade at heights from 1” to 6.” The small clip on top provides a “lock-in” stability to the wire and the large base provides excellent stability.
Specs:
• Covers 1” to 6” height
• Uses: Concrete slabs or driveways, for bigger spaces, anything over 8’ wide (if you’re not using rebar)
SLAB BOLSTER UPPER (aka BEAN BOLSTER)
Slab Bolster also known as continuous bar chair support, are used to support one layer of steel above another. The base is made of two even, continuous bars brought together by one top support bar connected by even spaced legs. The continuous bar support covers more distance with more support by placing multiple supports together.
Specs:
• Cover height ¾” to 5” in ¼” increments (Dayton Superior)
• Available in plain or epoxy coated
• Uses: Engineer specific, but normally used for bridges, highways, bigger projects
BEAM BOLSTERS
Beam Bolsters have a similar design as slab bolsters but do not have the continuous bar base. Instead, the top bar is supported by evenly spaced legs. The uses are similar to slab bolster but depend on the engineer and design of the project.
Specs:
• Cover height 1” through 5” in ¼” increments (Dayton Superior)
• Legs spacing 2 ½” centers
• Available in epoxy and steel
• Uses: Engineer specific, but normally used for bridges, highways, bigger projects
BAR CHAIR
Bar chairs are typically used for wide spaced, light steel in slab/deck construction. The bar chairs are lightweight and easy to install providing stability with their 4-point contact base. The foot is designed to set on most forming surfaces (Dayton Superior).
Specs:
• Cover height ¾” to 2,” ¼” increments
• Available in epoxy, plain, plastic tipped, plastic dipped and galvanized
CONTINUOUS MESH SUPPORT
Continuous mesh support is made up of two runner wires at the base one top supporting wire connected by evenly spaced legs in between. It’s used to support one layer of steel above another.
Specs:
• Cover height ¾” to 10” in ¼” increments
• Strong, resistance welded construction that withstands job site compressive loads without deforming, faster fulfillment times
• Available in plain, epoxy, or galvanize
• Uses: support steel on the soft material form surface
CONTINUOUS HIGH CHAIR UPPER
The continuous high chair upper is very similar to the continuous mesh support. These supports are available in carbon steel, stainless steel, and chromium steel, differentiating them from the mesh support as a sturdier option.
Specs:
• Cover height to 2” to 30” in ¼” increments
• Available in plain, epoxy, or galvanized
• Uses: Support steel or soft material form surfaces
There are many options when it comes to choosing a rebar support for your concrete pour. We suggest consulting your Outpost rep to find the best option for your jobsite!