Construction glossary · Concrete and masonry
What is rebar in construction?
Rebar (reinforcing bar) is deformed steel bar embedded in concrete to carry the tensile forces that concrete cannot resist on its own. US bar sizes run #3 through #18, and the size number is the bar diameter in eighths of an inch, so a #4 bar is 1/2 inch in diameter and a #5 bar is 5/8 inch. Estimators take rebar off in linear feet, convert to pounds with standard unit weights (a #5 bar weighs 1.043 lb per ft), and price it by the ton.
Updated June 2026 · Reviewed by the Ruh construction team
How a rebar mat is measured
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Book a walkthroughRebar shows up everywhere concrete does: footings, foundation walls, slabs, columns, beams, tilt-up panels, and grouted masonry cells. On a commercial set it lives on the structural sheets, in footing and column schedules, in typical details, and in the general notes that govern lap splice lengths, hooks, and concrete cover. The spec section is 03 20 00, Concrete Reinforcing, and ASTM A615 Grade 60 is the default material on most US jobs, with A706 where welding or seismic ductility is required. The structural engineer sizes and spaces the bars, a fabricator details and bends them from approved shop drawings, and ironworkers place and tie them in the field. The estimator owns the quantity. New estimators get burned in predictable ways: they take off what the plan shows and miss the lap schedule buried in the notes, they forget hooks, dowels, corner bars, and added bars at openings, they confuse welded wire reinforcement with rebar, and they price the fabricated steel but skip placement labor and accessories like chairs, bolsters, and tie wire. Read the general notes first, then the details, then the plan.
Rebar is taken off in linear feet by bar size, converted to pounds with standard unit weights, and summarized in tons (a #4 bar is 0.668 lb per ft, a #5 bar is 1.043 lb per ft, a #6 bar is 1.502 lb per ft). Quantities come from foundation and framing plans, schedules, and typical sections, with lap lengths and concrete cover pulled from the general notes. Fabricated supply is quoted in dollars per ton or per pound, delivered and tagged; placement labor is priced per ton and varies with congestion, so footings carry a lower rate than heavily reinforced walls or columns. Most estimators carry an allowance for laps, hooks, and waste, commonly somewhere in the 5 to 15 percent range depending on detailing, and count accessories (chairs, bolsters, tie wire) separately.
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How Ruh handles rebar
Ruh reads the structural sheets, pulls bar size, spacing, and extents from the plans and schedules, and runs the rebar takeoff, converting linear feet to pounds and tons by bar size. It prices that tonnage against the contractor's own price book, so the supply and placement rates are the contractor's real numbers rather than a generic average. The estimator gets a line-item draft to review, adjusts lap and waste allowances where the detailing warrants it, and signs off.
See concrete estimating softwareRebar: frequently asked questions
How much does each rebar size weigh per foot?+
Standard nominal weights are: #3 at 0.376 lb per ft, #4 at 0.668 lb per ft, #5 at 1.043 lb per ft, #6 at 1.502 lb per ft, #7 at 2.044 lb per ft, #8 at 2.670 lb per ft, #9 at 3.400 lb per ft, #10 at 4.303 lb per ft, and #11 at 5.313 lb per ft. These come from the ASTM bar tables and hold regardless of grade. To weigh a stick, multiply by length: a 20 ft stick of #4 is 20 ft x 0.668 lb per ft = 13.4 lb.
What grade of rebar is used in commercial construction?+
Grade 60 bar under ASTM A615, with a 60,000 psi yield strength, is the default on most US commercial work. ASTM A706 low-alloy bar is specified where bars get welded or where seismic ductility is required, and Grade 75 or Grade 80 shows up in heavy columns and mats to relieve congestion. Epoxy-coated or galvanized bar is called out where corrosion is a concern, such as parking structures and marine work. Always price the grade and coating in the spec, not what the yard usually stocks.
What is the difference between rebar and welded wire reinforcement?+
Rebar is individual deformed bars that are cut, bent, placed, and tied one at a time. Welded wire reinforcement (WWR, often called mesh) arrives as prefabricated sheets or rolls with designations like 6x6 W2.9/W2.9 and is common in lighter slabs on grade and toppings. The two are estimated differently, rebar by the ton and WWR by the square foot with a lap allowance, and one cannot be swapped for the other without the engineer's approval.
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Figures on this page are illustrative. Construction estimates depend on project-specific conditions, source documents, market pricing, and professional judgment. Ruh's AI assists the estimator and does not replace professional review: your team reviews, validates, and approves every estimate, bid, and pricing decision.