Ballast removal clears the river rock or pavers from a ballasted roof so the membrane underneath can be inspected, restored, recovered or replaced. Strong removes rock from 0.75 inch to 2.5 inches with dedicated vacuum equipment, which is faster and creates less dust and manual handling than shovels and wheelbarrows. The rock can then be reused, recycled or hauled away.
Ballasted roofs use loose stone or paver ballast to hold the membrane in place, and before any re-roof, recover, or inspection can happen, that ballast has to come off safely and completely.
We remove and dispose of aggregate ballast using mechanical scoop equipment where roof access allows, minimizing the manual labor and timeline of a full hand-removal.
Ballast removal looks simple until you’re managing dust, disposal logistics, and roof loading on an occupied building. We plan the removal and disposal route before the first scoop, keeping the site clean and the schedule on track.
That planning is what keeps ballast removal a fast first step instead of a bottleneck on your project.
We plan rock removal backward from the next phase of the roof, because bare membrane should not sit exposed for long. A typical project runs like this.
| Spec | Typical Value |
|---|---|
| Removal method | Dedicated vacuum equipment |
| Rock size handled | 0.75 in. to 2.5 in. river rock |
| Roof types | Ballasted single-ply, IRMA and tar-and-gravel roofs |
| Pavers | Removed separately, by hand or crane |
| Typical ballast load | Typical: about 10 lb per sq ft or more |
| Rock disposition | Reuse, recycling or disposal |
| Follow-on work | Restoration, recover or replacement |
Ballast removal is priced by volume, reach and what happens to the rock afterward. These are the main drivers.
Roof area and ballast depth set the tonnage. Deep or uneven rock, common where ballast has shifted over the years, adds volume.
Building height, how close equipment can park and the roof layout set how far the vacuum has to reach and how often it moves.
Pavers, rock packed against curbs and areas around equipment need hand removal, which is slower than vacuum work.
Reuse on the finished roof, recycling and landfill disposal each carry different handling, hauling and fee costs.
Removing rock in sections that match the next crew's pace takes more coordination but keeps the membrane from sitting exposed.
Strong Contractors takes on spray foam, coating, and ballast removal projects outside Colorado, bringing our own crews, equipment, and project management to the job. Before we bid an out-of-state project, we confirm that state’s licensing, registration, and permit requirements so the work moves forward cleanly.
Because the membrane under the rock is what is being inspected, restored or replaced. Ballast hides punctures, open seams and wet areas, and a coating or recover cannot bond to a surface covered in stone. Removal also takes a significant dead load off the roof, which matters when the new system weighs less.
Strong uses dedicated vacuum equipment for river rock from 0.75 inch to 2.5 inches, and has completed numerous large-scale commercial ballast removal projects this way. Crews do not shovel stone into wheelbarrows and carry it across the roof. That makes removal faster, keeps dust and debris down and cuts the manual handling that puts workers at risk.
Often, yes. At the Douglas County Justice Center, a courthouse and county jail sat under a ballasted EPDM roof. Strong applied a liquid coating over the existing membrane, laid a protective mat over it to resist punctures and put the original river rock back. Coating over the membrane instead of tearing it off was planned to minimize both buildings’ exposure to the elements during reroofing. The project led to a five-year contract with the county.
Yes. Strong’s employees are background-checked, so crews can be cleared for government sites. On the Douglas County Justice Center, a crew of 16 passed background checks to work above the courthouse and jail. The county’s facilities manager noted the job stayed on schedule and within budget with no change orders.
An IRMA, or inverted roof membrane assembly, places the insulation above the waterproofing membrane, with ballast holding the insulation down. Strong removes ballast from IRMA roofs as well as standard ballasted single-ply roofs. Once the rock is off, the insulation boards can be lifted to reach the membrane, then reused or replaced if damaged.
Pavers are handled separately from rock, usually by hand or by crane. At UCHealth Memorial Hospital, a crane would have interfered with helicopter landings, so crews removed 964 concrete pavers, each weighing 40 pounds, by hand and carried them out through the building on elevators.
Rock ballast typically weighs about 10 pounds per square foot or more, depending on stone size and depth. On a 50,000-square-foot roof, that is roughly 250 tons of stone. That weight is also what holds a loose-laid membrane down in the wind, so rock should come off only as fast as the next phase can secure the roof.
Yes. On a built-up tar-and-gravel roof, much of the gravel is set into the asphalt, so the loose stone comes off first and the surface is prepared for the new system. Strong took that step on a tar-and-gravel roof at Eglin Air Force Base before the new spray foam and urethane system went on.
Gravel on a roof is not there for looks. On a ballasted roof, the weight of the stones holds the membrane in place, with no glue or fasteners.
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