How Much Does it Cost to Install Steel Reinforcing Bars?

Steel reinforcing bars, known as rebar, are most commonly used to provide structure and tension support in concrete structures. Rebar generally costs about $0.75 per foot with slight price variations for thinner or thicker sticks. Usually sold in 2-foot lengths, prices can range from $1.40 to $1.84.

The surface of the bar is "deformed" or patterned to provide a good contact area for concrete adherence. Early concrete structures did not use reinforcement bars, but rather broken pottery shards as reinforcement materials.

Steel reinforcement is generally divided into two types.

• Primary reinforcement is designed to support the overall load that construction is intended to carry, such as the rebar you might put into a concrete retaining wall. It holds the structure together.
• Secondary reinforcement is employed to maintain durability and aesthetics. It helps provide resistance to cracking and stress caused by temperature fluctuations and natural shrinkage of concrete as it dries. Patios, cement foundations and freeway overpass supports are some of the most common areas in the US where you will see this type of reinforcement.

Rebar is also used to hold other steel bars in position. This helps accommodate loads and stresses that couldn't be handled by rebar alone. Some rebar is used in an exposed condition. The Leaning Tower of Nevyansk employs exposed rebar both for appearance and to help keep the tower together.

Rebar comes in a number of different grades. The grade tells you how many thousands of pounds per square inch the rebar can withstand. This is usually listed as "ksi." A grade of 60 ksi means that rebar can withstand 60,000 pounds per square inch of tension before it deforms. Most typical home improvement projects will use Grade 40 rebar.

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Factors to Consider When Purchasing Rebar

When buying individual pieces of rebar, the price varies based on thickness and length. Thickness affects the price less than length does. Most home projects use 3/8" to 5/8" rebar.

Some rebar suppliers actually charge less per foot the longer the bar is. For example, a 10-foot stick of half-inch rebar is about $4.47. That same bar in a 2-foot length is about $1.90. Because the cost of rebar is dependent on the price of raw steel, prices don't change much from store to store.

Corrosion resistance can affect the price of an individual stick of rebar. Epoxy-coated rebar costs 10 cents per pound more than uncoated rebar (known as black rebar). Used primarily in construction where the structure is going to be exposed to marine-like conditions, it must be inspected before being installed. Nicks in the epoxy can expose the steel to corrosion.

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Cost Per Ton

One ton of rebar can contain a varying number of sticks depending on the thickness. These calculations are of the number of 20-foot sticks of rebar in one ton, based on how much one stick weighs.

• 3/8" x 20' = 266 sticks
• 1/2" x 20' = 150 sticks
• 5/8" x 20' = 96 sticks
• 3/4" x 20' = 67 sticks

Ordering by the ton usually gives you a lower price per stick than by purchasing one ton of sticks individually. However, the price of rebar is prone to fluctuations in the steel market. While prices for such commodities can vary from day to day, in spring 2007, the steel price was fluctuating so wildly that purchasers were told that their quotes were only good for an hour.

One ton of rebar could be had from Chinese suppliers for $400 to $800 for 40-foot sticks. American suppliers were charging around the $650 price range. Many suppliers have a minimum purchase that can range from 10 tons to 100 tons. These suppliers are generally selling to major construction jobs. If all you're doing is putting in a driveway or building a retaining wall, you're better off purchasing the sticks individually.

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Cost Per Pound

Rebar is not normally sold by the pound at hardware stores, and industrial applications tend to go by the ton. However, a typical stick 1 foot long by 1/2" diameter weighs about .67 pounds or 2/3 pounds. At an average price of $0.75 per foot, that comes out to about $1.12 a pound in single sticks. However, quantity and size affect the end price. By the truckload, rebar costs between $0.60 and $0.80 per pound.

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Common Rebar Sizes

Most hardware stores identify rebar by its diameter. However, some will use industry sizing or metric sizing. The smaller the number, the smaller the diameter:

• Size 3 -- Metric Size 10 -- 3/8" diameter
• Size 4 -- Metric Size 13 -- 1/2" diameter
• Size 5 -- Metric Size 16 -- 5/8" diameter
• Size 6 -- Metric Size 19 -- 3/4" diameter
• Size 7 -- Metric Size 22 -- 7/8" diameter
• Size 8 -- Metric Size 25 -- 1" diameter
• Size 9 -- Metric Size 29 -- 1 1/8" diameter

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3 Uses for Rebar

Driveways & Patios

You can use 3/8" rebar (size 3) for concrete slabs such as driveways and patios. When building your grid of rebar, it should begin 15 inches from the edge with the rebar spaced at 18 inches. Any point where the rebar crosses should be tied together with rebar tie wire. While rebar can be welded, this is not advisable as a substitute for tie wire. Tie wire allows for flexibility while welds will break. The grid itself will have to be suspended to about the halfway point of the depth of the slab. Rebar supports, sometimes called "chairs", are often used for this purpose. They hold the grid at a given height while the concrete is poured. Finally, at the corners you should use rebar that has been bent to a 90 degree angle. Simply using two straight sticks as a corner will compromise the ability of the rebar to resist excessive flexing and cracking.

Walls & Columns

For walls, columns, and piers, 1/2" rebar is recommended. Spacing for a column depends on its expected load capacity. Some applications allow 500mm (about 20 inches) between vertical bars, but some contractors feel more comfortable with 12 inches. Concrete block walls use one stick per cell in the block.

Foundations

Building foundations need 5/8" rebar or thicker. The requirements for spacing will vary by local code due to numerous factors that influence proper construction. For example, a region prone to seismic activity will have different requirements than those on less active ground. The depth of the frost line and the amount of shifting in the native soil can also affect requirements for reinforcing foundations. The only thing that is constant is that reinforced foundations last longer than un-reinforced foundations. For all construction projects where such stability is a consideration, always check with your local codes.