Reinforced Concrete Demolition: Special Considerations for Contractors

TL;DR: Reinforced concrete adds three things to a tear-out plan: extra weight (155 vs 150 lbs/cu ft), longer break-up time, and the need to plan for the steel. Standard rebar and wire mesh are not a disposal problem. Post-tensioned slabs are a different animal and belong with a specialty demo crew. Use the tear-out calculator with the reinforced-concrete option to price the weight and hauling correctly.

Every slab you tear out is going to have some reinforcement in it. On residential driveways it's usually wire mesh. On commercial pads and foundations, it's rebar. On parking decks, elevated slabs, or post-tensioned floor systems, it's steel strand you have to respect or it kills someone. This piece walks through the practical demolition side and how to plan the disposal.

Three kinds of reinforcement, three plans

Wire mesh (welded wire fabric, WWF, 6x6-10/10 and similar)

The most common residential reinforcement. Sheets of welded wire, usually 6x6 grid with 10-gauge wire, laid in the slab before pour. Modern equivalents run W1.4 or W2.9.

Demo behavior: mesh holds broken pieces together, which makes them easier to load in some ways (bigger, more stable chunks) and harder in others (chunks are floppy and awkward). Doesn't slow the actual break-up much.

Loading: skid-steer forks work great for mesh-reinforced chunks. Bucket loading fights the wire.

Disposal: standard concrete recycling accepts it. No prep needed.

Rebar (#3 through #6 typical, #8 and up on structural)

Most commercial slabs, foundation walls, structural elements. Deformed steel bars, sized in eighths of an inch (#4 = 4/8" = 1/2" diameter, and so on).

Demo behavior: rebar bends before it breaks. Break-up moves the slab into pieces still connected by rebar, which then have to be cut. This is the "chain-of-slabs" phase every rebar-slab demo goes through.

Loading: cut with an excavator shear, hydraulic cutter, or torch. Small residential pieces can be cut with a portaband or reciprocating saw once exposed. Piece size for hauling depends on truck bed dimensions.

Disposal: standard concrete recycling accepts it with the rebar attached. No prep needed beyond making the individual pieces small enough to load safely.

Post-tensioned cable (PT)

Higher-end commercial slabs, parking garages, some residential foundations built after 1980. Steel strand tensioned to 25,000+ pounds and grouted or greased in the slab.

Demo behavior: dangerous. A tensioned cable stores enormous energy. Cut in the wrong location, without proper detensioning, and the cable snaps back with lethal force. Death and serious injury cases are documented in the trade literature.

Loading: not a general contractor job. Hire a specialty PT demo crew who will locate cables (ground-penetrating radar or as-built plans), detension them systematically, and then demo the slab. This is a real cost line on any PT project.

Disposal: same as regular reinforced concrete after the strand is dealt with. Standard yards accept it.

If you find you have a PT slab and didn't plan for it: stop, get the as-builts, and call a specialist before touching it.

The weight math changes

Standard concrete: 150 lbs per cubic foot solid. Reinforced concrete (typical residential/commercial): 155 lbs per cubic foot solid. Asphalt: 145 lbs per cubic foot solid. Broken concrete pile: ~135 lbs per cubic foot with air gaps between chunks.

That extra 5 lbs per cubic foot might not sound like much until you scale it up.

1,000 sq ft x 4-inch slab, plain: 333 cu ft x 150 = 50,000 lbs = 25 tons 1,000 sq ft x 4-inch slab, reinforced: 333 cu ft x 155 = 51,600 lbs = 25.8 tons 1,000 sq ft x 6-inch slab, plain: 500 cu ft x 150 = 75,000 lbs = 37.5 tons 1,000 sq ft x 6-inch slab, reinforced: 500 cu ft x 155 = 77,500 lbs = 38.75 tons

On a 6-inch reinforced slab you're up over a ton compared to the plain equivalent. That's roughly one extra pickup-truck load worth of weight to move.

The break-bulk factor (broken debris takes ~1.2x the volume of the original solid) applies the same way to reinforced concrete. Where reinforced changes the math is that the extra weight per volume means you'll hit truck axle limits before you visually fill the container.

The tear-out calculator has a "reinforced" toggle. Use it. On a big job the wrong density assumption is a several-hundred-dollar hauling error.

Break-up methods, ranked by job size

Handheld jackhammer (electric or pneumatic, 60-90 lb)

• Good for: patches under 100 sq ft, thin slabs, tight spaces
• Bad for: anything larger, or rebar-heavy slabs
• Speed: slow. Painful on rebar. Fine for small residential.

Skid-steer breaker attachment (1,000-1,500 ft-lb)

• Good for: 4 to 6 inch residential slab up to a few hundred sq ft
• Bad for: heavy commercial slab, deep foundation walls
• Speed: 3 to 4x faster than handheld

Mini-excavator with hydraulic breaker (5,000+ ft-lb, e.g. Cat 305 class)

• Good for: most residential and light commercial tear-outs
• Bad for: nothing in that range. This is the workhorse.
• Speed: fast. Standard residential driveway in 3 to 6 hours of break-up.

Full excavator with breaker or shear (20-ton class)

• Good for: commercial pads, foundation walls, industrial slabs
• Bad for: overkill for residential
• Speed: fastest, but you need site access for the machine

Saw-cut plus break

• Almost always the right first step. Saw-cut the slab into manageable rectangles, then break each one. This produces clean edges around anything you're keeping and makes the break-up predictable.
• Fresh diamond blade water-cools better than dry-cut. Water reduces silica exposure.

Diamond wire saw

• Specialty tool for heavy structural work. Bridge decks, thick foundation walls, precise cuts around embedded items.
• Not something to buy for a one-off. Rent with an operator.

Rebar handling on-site

Once the slab is broken and the chunks are connected by rebar, you have four options.

1. Leave it attached, ship it as-is. What most contractors do for residential and light commercial. Requires a yard that accepts embedded rebar. SMSG does.

2. Cut it flush at each chunk. Cleaner load. Slower. Adds a full labor step to the demo. Useful mainly if the disposal facility charges by yard and cleaner chunks pack denser.

3. Extract all rebar for metal recycling before disposal. Rarely worth it on residential. Sometimes worth it on very large commercial jobs where you're generating a truckload of steel. Scrap-yard rates on rebar are usually $50 to $150 per ton depending on market.

4. Ship to a facility that doesn't accept rebar. Some do not. Blount County Landfill accepts it. Some other regional facilities require full extraction. Ask before you haul.

Our position: bring it in with the rebar attached. We magnet-separate during crushing. The steel goes to metal recycling on our end and you don't pay for the extraction time.

Deeper dive on this specific question in Do I Need to Separate Rebar from Concrete?.

The reinforced tear-out weight examples

Let's price two real reinforced jobs.

Job A: 800 sq ft residential driveway, 4-inch, wire mesh, in Alcoa

• Weight: 800 x 0.333 ft x 155 lbs = 41,300 lbs = 20.6 tons
• Volume broken with 20% break-bulk: 800 x 0.333 x 1.2 = 320 cu ft = 11.9 cu yards
• Container fit: one 20-yd roll-off handles the volume, but 20.6 tons is over standard axle limits. Split into a 10-yd (holds ~6 tons) plus 2 dump trailer trips, or use two 10-yd containers.
• Blount County pricing (self-haul, dump trailer): 3 trips = $225 + $175 + $175 = $575
• Tipping at SMSG: $0
• Total disposal: $575
• Same job to landfill: $575 + (20.6 x $60) = $1,811

Job B: 3,500 sq ft commercial pad, 6-inch, rebar on 18-inch centers, in Farragut

• Weight: 3,500 x 0.5 ft x 155 lbs = 271,250 lbs = 135 tons
• Volume broken with 20% break-bulk: 3,500 x 0.5 x 1.2 = 2,100 cu ft = 78 cu yards
• Container fit: this is roughly 10 to 12 dump-truck loads or 6 to 8 large roll-offs
• Over the volume threshold. Get a project quote.
• Rough disposal at SMSG under current promo: hauling cost only. Roughly 10 dump truck trips at Knox County rate = $4,250
• Same job to Knox landfill: $4,250 + (135 x $60) = $12,350

The reinforcement adds a little to the weight and a lot to the break-up labor. The disposal side is dominated by whether you're paying tipping fees or not.

Safety points that matter

• Silica dust. Cutting and breaking concrete produces respirable crystalline silica. OSHA's Table 1 spells out what controls are required. Water on the cut, HEPA vacuum on the tool, or supplied-air respirator. This is not optional.
• Rebar whip. Cut rebar under tension can spring. When cutting connectors between broken chunks, expect movement.
• Flying fragments. Hydraulic breakers throw pieces surprisingly far. Set a working radius, keep other trades out.
• Slab drop-through. Suspended slabs can collapse when partially cut. Shore or demo from above with awareness of what's below.
• PT strand. Covered above. Do not cut what you did not detension.
• Overhead utilities. Excavator booms in residential yards find low-hanging power drops. Look up before you swing.

Beyond OSHA, TDOT and TOSHA post updated silica guidance periodically. The 50 microgram/cubic meter PEL is the number.

Foundation walls and footings

Different animal from slab. Same principles but different geometry.

• Break from the top down for walls. Excavator sits above, breaks in vertical passes.
• Undermining footings without proper shoring collapses adjacent structures.
• Deep footings sometimes surprise you with a second, thicker keyway pour underneath the visible slab.
• Rebar in walls is usually vertical bars every 12 or 16 inches with horizontal ties. Cut the bars as the wall comes apart.

Weight math is the same as slab: 150 for plain, 155 for reinforced, 135 broken.

Bridge decks and infrastructure

If you're on a bridge deck job for TDOT or a private industrial project, you're almost certainly working with a specialty crew already. A few notes for the general contractor observing:

• Bridge deck removal typically uses hydro-demolition (high-pressure water jetting) or full-depth saw-cut and lift. Hammering directly on a bridge deck damages the underlying structure.
• The debris stream from a bridge deck is contaminated with deck sealants, epoxy overlays, and sometimes chloride-heavy salted concrete. Check with the receiving facility.
• TDOT tracks recycled content on infrastructure jobs. Aggregate specs include RCA in many sub-base applications now.

For general contractors seeing a bridge deck load coming their way: call us before hauling, so we can talk through whether we can accept it. Most standard cured deck concrete is fine, but coatings and treatments vary.

Getting the disposal side right

Once you've broken it, someone has to move it and dump it. That's where most of the reinforced-concrete cost overrun happens.

• Use the calculator with the reinforced toggle. The weight prediction changes.
• Don't fill containers by volume. Fill by weight. A 20-yd roll-off with reinforced 6-inch slab hits axle limit before it looks full.
• Split loads over more trips rather than overweight a truck. TDOT will find you eventually.
• Pick a disposal yard that accepts embedded rebar. Everything at SMSG accepts it. Not every yard in the region does.
• If you're rebuilding on-site, order the base aggregate on the way out. Sizing on the gravel calculator, inventory on the materials page.

For a specific reinforced tear-out job, request a quote or call (865) 999-0857.

Related reading

• Do I Need to Separate Rebar from Concrete?: the extraction-vs-embedded question in detail.
• How to Break Up a Concrete Driveway: DIY Guide: the residential end of tear-out, tools and technique.
• How to Load a Truck for Concrete Drop-Off: loading practice that matters more with reinforced chunks.

Price your reinforced tear-out on the concrete tear-out calculator or call (865) 999-0857. Yard at 245 Brookdale Rd, Maryville, TN. Mon-Fri 7am-5pm, Sat 7am-noon.