How Gravel Roof Vacuuming Works, and When a Crew With Shovels Is Cheaper
A trailer vacuum on the ground, hose on the roof, and 40 tons of stone gone in a day or two. Here is how the job actually runs, and the cases where a vacuum is the wrong tool.
The short answer
Gravel roof vacuuming uses a trailer-mounted industrial vacuum parked at grade to pull gravel or stone ballast off a flat roof through a reinforced hose. The crew stays on the roof directing the hose head; the heavy lifting happens on the ground. On an embedded pea-gravel built-up roof a crew clears roughly 10,000 to 15,000 square feet a day; on loose river-rock ballast closer to 6,000 to 8,000. For a defined area such as the gravel piled around rooftop units, a crew with shovels and bags is faster to mobilise and cheaper, and we do both. Our gravel roof vacuuming and ballast removal page covers the service itself; this post is about how the day runs.
What the vacuum truck needs from your site
Three things decide whether a vacuum job goes smoothly. First, a place to park the unit within hose reach of the roof: a drive lane, a dock apron or a corner of the lot, for the full day, with the dumpster or haul truck close by. Second, a route for the hose up the building face that does not block an exit, cross a tenant entrance or run over a gas meter. Third, somewhere the stone goes. On most jobs it is hauled and disposed of; on a ballasted roof that is staying in service it is staged on site in totes or on pallets and returned afterwards. If the roof has HVAC air intakes, tell the contractor before the day, because the sequence around those intakes is planned, not improvised.
How the crew works the roof
Fall protection goes up first. The hose comes up the face and across the roof in sections, and two or three crew members walk the hose head across the field in lanes, the way you would mow a lawn, pushing stone into the intake. On a built-up roof the gravel is partly set in asphalt, so the head is worked at an angle to break it free and some of the flood coat comes with it. On loose ballast the head glides and the rate roughly doubles. Behind the hose, someone is looking at the membrane as it appears: open laps, splits, blisters, ponding stains, and the condition of the flashing at every curb and drain. That read is the real product of the day. The stone was hiding it.
Why vacuuming beats wheelbarrows on a whole roof
An inch of roof gravel weighs four to five pounds a square foot, so a 20,000 square foot roof is carrying 40 to 50 tons. Moving that by hand means loaded wheelbarrows crossing the membrane all day, a chute or a hoist at the edge, and a crew that is exhausted by noon. The membrane takes the punishment, which matters on a ballasted EPDM roof that is supposed to stay in service. A vacuum keeps the mass moving through a closed hose, controls the dust, and clears in a day or two what takes a hand crew most of a week. On anything above a few thousand square feet, the vacuum wins on cost as well as on the roof.
When a crew with shovels is the cheaper call
A vacuum unit costs money to mobilise whether it runs for an hour or a day. For a small, defined area, that mobilisation is most of the bill, and a roofing crew with shovels, bags and a hoist clears it for less. The common cases: gravel piled around HVAC units and condensers so a technician can service them; a drain or scupper that keeps clogging; a walkway path crews use every week; a leak that cannot be traced through stone; or a single bay of a roof ahead of a repair. Those jobs also do not wait for vacuum availability, which in season can be weeks. If the area is under a couple of thousand square feet and reachable, ask for a hand-removal price first.
Capacity is the honest constraint
Chicagoland has far more gravel roofs reaching end of life than it has vacuum trucks to clear them, and the handful of operators that run the big units are booked solid from spring through fall. That is why we tell owners and contractors to raise the removal the day a re-roof or solar install is first scheduled, not the week before the crew arrives. Winter is often the easiest time to get a unit, as long as the roof is dry and the stone is not frozen into the flood coat.
Talk to us
Leaders Roofing has been on Chicagoland flat roofs since 1996 and holds an Illinois Roofing Unlimited License (#104.010248). We vacuum whole roofs, clear areas by hand, and carry the repair, coating or re-roof that follows under the same contract. Send the address, roughly how much of the roof needs clearing and what the removal is for, and we will come back with one total price that includes hauling and disposal. Details on the gravel vacuuming and ballast removal page, or call (708) 847-5418.