Concrete demolition used to mean hauling a corded breaker or a gas-powered jackhammer to the site, along with a generator and a long extension cord. The newest cordless rotary hammers and demolition hammers have changed that calculation, with impact energy figures that were unheard of in battery tools a decade ago. The launches that surface at the big concrete and masonry trade events keep pushing those numbers higher, and the new concrete and masonry tools announced at World of Concrete 2022 already showed how fast the category was moving. For a contractor, the practical question is not which brand has the loudest launch, but how to read the specifications and match a hammer to the work.
Start With the Surface: Preparing Old Concrete for New Work
Before any hammer earns its keep, the project plan has to be right. New concrete only performs as well as the surface it sits on, and a slab that is cracked, spalled, or contaminated needs assessment before anything else. The decision tree starts with one question: can the existing concrete be repaired and reused, or does it have to come out? The answer sets the scope of the demolition work and the size of the tool you will need.
- Inspect the slab for cracks wider than about 1/8 inch, spalling, and signs of water damage.
- Sound the surface with a test hammer to find hollow areas where the concrete has delaminated.
- Remove loose material, oil stains, curing compounds, and laitance before any repair or overlay.
- Decide between full demolition and a bonded repair based on the depth and spread of the damage.
- Clean the prepared surface and keep it damp but free of standing water before placing new concrete.
Contractors who want the full sequence can follow the steps for how to pour new concrete over an old concrete surface, which walks through the prep and placement details. The pattern is consistent: the demolition tool you choose matters less than the preparation that happens before it, and the two go together. The right hammer makes removal fast, and the right prep makes the new concrete last.
When Full Demolition Is the Right Call
Full removal is usually justified when a slab is cracked through, the reinforcement is corroded, or the surface is too far out of level to correct with an overlay. A cordless breaker with an SDS Max shank handles that work in sections, cutting through a 4-inch slab with a chisel before the debris is loaded out. When the damage stops at the top layer, a scarifier or grinder followed by a bonded overlay can save most of the removal cost, and the crew stays smaller. Budget about 30 percent of the repair time for preparation and cleanup.
Two measurements dominate the prep estimate: the area of the pour and the condition of the base. A clean, sound slab can take an overlay the same day; a contaminated one can add a day of grinding and washing. Build the contingency into the bid before the hammer shows up.
How to Read a Demolition Hammer Spec Sheet
Manufacturers publish a handful of numbers on every hammer, and three matter most: impact energy, blows per minute, and tool weight. Impact energy, measured in foot-pounds for larger hammers and joules in metric markets, describes the force of each strike. Blows per minute describes how often the mechanism fires. The two work together, and neither tells the whole story alone.
| Hammer class | Shank | Impact energy | Typical work |
|---|---|---|---|
| Compact rotary hammer | SDS Plus | 1.5 to 3 ft-lbs | Anchoring, small holes, light chipping |
| Full-size rotary hammer | SDS Max | 5 to 12 ft-lbs | Core drilling, chipping, medium demolition |
| Cordless demolition hammer | SDS Max or hex | 10 to 20 ft-lbs | Breaking slabs, footings, heavy chipping |
| Gas-class cordless breaker | Hex | 20 to 33 ft-lbs | Heavy breaking, production demolition |
The ranges shift every season. A recent 18-pound cordless demolition hammer was rated at 11.4 ft-lbs of impact energy, a number that belonged to corded breakers a few years ago. Brands tend to save their biggest hammer launches for the same industry events, and the Milwaukee Tools 2020 new product release event shows the same mix of breakers, rotary hammers, and dust management leading the lineup.
When comparing two hammers, ask three questions: how does the impact energy compare at the same weight, how long does the battery last under load, and what does the dust solution cost? The answers separate a spec-sheet winner from a jobsite winner.
Impact Energy vs Blows Per Minute
High blows per minute with moderate impact energy suits chipping tile, removing thin toppings, and slotting concrete. High impact energy with lower blows per minute suits breaking thick sections, because each strike does more work. A hammer rated 11 ft-lbs at 1,000 blows per minute will chew through a slab faster than a 3 ft-lb hammer at 4,000 blows per minute, even though the smaller tool sounds busier.
What a 10+ ft-lb Hammer Can Do
In practical terms, a hammer in the 10 to 12 ft-lb class breaks a 4-inch slab section noticeably faster than a compact rotary hammer, and it weighs roughly twice as much. The trade-off is fatigue: an 18-pound tool hung on a rig or held low on a wall demands a different work rhythm than a 7-pound drill. Plan the crew and the lifting aids before you spec the hammer.
SDS Max vs SDS Plus: Matching the Shank to the Job
The shank is the business end of the system. SDS Plus and SDS Max are the two dominant standards in cordless hammers. SDS Plus tools use 10 mm shanks and suit holes up to about 1 inch plus light chipping. SDS Max tools use 18 mm shanks, transfer more energy, and handle bits up to 2 inches and larger. The two are not interchangeable, and adapter kits that bridge them add length and reduce energy transfer.
Bits and Chisels for Breakout Work
Chisel selection matters as much as the hammer. Point chisels concentrate force for starting cracks, flat chisels remove material in layers, and spade chisels work through soft or frozen material. Carbide-tipped chisels hold an edge longer in abrasive concrete, and the price difference pays off on jobs measured in days. Keep the chisel sharp, because a dull edge turns impact energy into heat instead of breaking action.
Before you commit to a breaker, confirm whether the existing concrete can carry a bonded repair. The process for how to bond new concrete to hardened concrete covers the surface preparation and bonding requirements, and it can change the tool list from a demolition crew to a grinder and a pump. That swap saves money on some jobs and loses money on others, which is why the assessment happens before the equipment rental.
Dust Control and Vibration: Specs That Protect the Crew
A hammer that pulverizes concrete also produces silica dust and transfers vibration to the operator’s hands and arms, and both are regulated on most jobsites. Dust extraction attachments and shrouds capture material at the source, and vacuum connections keep the work area clean enough to see. The annual concrete industry show is where these accessories debut next to the hammers, and it is the easiest place to compare them hands-on.
Vibration Exposure and Work Rotation
Hand-arm vibration exposure is measured in meters per second squared and tracked across the workday. Exposure limits vary by region, but the pattern is the same everywhere: long stretches on a breaker push operators toward the limit, and rotation between tasks is the standard control. Recording exposure per tool helps crews plan the rotation ahead of time.
Dust Collection First, Then More Power
If the budget covers one accessory, make it dust control. A shroud and a class H vacuum keep silica out of the air and protect everyone downwind. A more powerful hammer without dust control just makes more dust faster, and the fines from concrete demolition are the ones that linger longest in the lungs.
Battery Power and Charging for High-Energy Tools
High-impact hammers draw current in bursts that stress even large battery packs. A 12 Ah high-output pack runs a breaker measurably longer than a 5 Ah pack, and the charger matters just as much. Rapid chargers refill a pack in under an hour, and the newest systems keep several packs cycling through the day so the tool never waits on the charger.
The 2026 announcements included a 3600 W power supply with a 6 kWh storage capacity, sized to run chargers and lights on sites without reliable grid power. That buffer changes the math for crews that previously rented a generator just to keep batteries topped up, and it makes the all-cordless demolition crew a realistic option on more jobs.
- Check the amp-hour rating, not the voltage alone, when comparing packs.
- Match the pack to the draw: high-output cells for breakers, standard cells for drills.
- Keep two packs minimum for the hammer you use daily.
- Use the rapid charger setting when turnaround time matters.
- Retire packs that swell, overheat, or die under load.
Cold weather is the hidden battery killer. Packs that sit in a truck overnight in freezing temperatures deliver fewer blows per charge, and charging a frozen pack shortens its life. Keep spare packs in a heated cab or an insulated box during winter pours.
Building a Cordless Concrete Toolkit
The tools already in the truck shape what gets bought next. Battery platforms are the real investment, and contractors usually standardize on one or two systems. The shift did not happen overnight; the new tools of 2016 from Bosch, Milwaukee, Makita, and Dewalt show how far the cordless transition had already come, and the pace has only accelerated since.
A practical kit grows in stages rather than all at once, and each stage pays for itself before the next one starts.
- Pick the platform with the widest lineup for your trade.
- Buy high-output batteries before the second hammer.
- Add dust extraction before adding another breaker.
- Rent before buying tools you will use less than once a month.
- Re-evaluate the kit when impact energy jumps a full class.
Spec sheets will keep changing, but the evaluation habit stays the same: read the impact energy, weigh the shank standard, budget for batteries and dust control, and compare options against the World of Concrete show insights before committing. A hammer is a long-term purchase, and the data, not the launch hype, is what earns it a place in the truck.