Asphalt Spreader Box: Types, Screed Depth and Tonnage

An asphalt spreader box is a steel box with no bottom and an adjustable strike-off edge at the back. Hot mix goes in the front, the box is dragged forward by a dump truck, skid steer or tractor, and the rear edge (the screed) leaves a strip of mix at whatever loose depth you set. It does not have the heated, vibrating screed, augers or conveyors of a self-propelled paver, so it costs far less and needs a smaller crew, but it also leaves more work for the rakers and the roller.

This guide covers the main types of spreader box with real manufacturer specs, how a drag box is set up and pulled, how deep to set the screed so the mat ends up the right thickness after rolling, where public specs allow one, and a worked driveway example with tons and truckloads.

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Two meanings of "spreader box"

The term shows up in two different kinds of road work, and searches mix them up:

Hot mix spreader box. The subject of this guide. It is towed or pushed, and gravity plus the forward pull lays the mix. Used for driveways, lanes, trench patches, widening and shoulders.
Slurry or micro-surfacing spreader box. A box dragged behind a slurry truck to spread a thin emulsion mix. Georgia DOT's pavement training manual calls for one with augers and a width adjuster. Different equipment, different job.

Types of asphalt spreader box, with real specs

Figures are from each maker's own product pages and manuals; these are examples, not a ranking.

Style and example	How it moves	Width	Loose depth setting	Weight
Tow-behind drag box: J. Pyott Drag-A-Box Contractors Model CE 7-12	Pinned to a hitch under a dump truck's rear frame; fully mechanical	7 to 12 ft, set with hand screw jacks	0 to 8 in, each side set separately	Under 1,200 lb with all components
Paver box: Melecio Attachments 8, 10 and 12 ft boxes	Dragged slowly while it is filled with mix	10 ft box is 120 in inside; two dividers for narrower passes	0 to 6 in with hand-crank jacks	1,240 lb (10 ft box, 1/4 in Grade 50 steel)
Skid steer spreader: Bobcat Soil and Asphalt Spreader	Mounted on a Bobcat loader through the Power Bob-Tach system; hydraulic	Side wings set any path from 5 in to 6 ft	Blade leaves up to 4 in	1,488 lb
Skid steer asphalt float: Simex ST 160 / ST 200	Loader-mounted; hydraulic width and side shift	Hydraulically adjustable laying width	0 to 100 mm (0 to 4 in), set mechanically per side	610 and 675 kg (1,350 and 1,485 lb)

Truck-towed boxes take mix straight from the dump body, with no loader feeding them, and the wider ones cover a 10 to 12 ft driveway in one pull. Loader-mounted spreaders are narrower and thinner but can work offset: Bobcat says its hydraulic offset shifts the material guide up to 6 ft to the right, and Simex says its ST 160 and ST 200 can lay a sidewalk or a road widening without the loader driving over the fresh mix.

Check the loader before buying a skid steer spreader

Hydraulic spreaders need a loader that can carry and power them. Simex lists a required oil flow of 45 L/min (12 gpm) at 200 bar (2,900 psi) for its ST line, and it states that the user is responsible for confirming the loader suits the attachment's weight and specs. Bobcat lists compatible models, from the S450 and T450 up through the S86 and T86, plus the L95 compact wheel loader. Compare the attachment weight with your loader's rated operating capacity, and the flow figure with the auxiliary hydraulics, before you order.

How a tow-behind drag box is run

J. Pyott's operating manual for the Drag-A-Box gives a useful step-by-step for a 10 ft wide, 3 in asphalt pass. Paraphrased:

Crew. Two people minimum (the truck driver and a box operator). The maker says a five-person crew gets the most done: a driver, a lead who runs the box, an assistant, and two people on shovels and rakes. Big jobs add a roller operator.
Set width and depth before the mix shows up. Crank both sides out equally until the box is 10 ft inside, then set the screed jacks using the depth marks on the skids, which step in 1 in increments from a double "zero" mark. Width should never be changed while the box is loaded.
Coat the box. Put release agent on before you start. The maker advises against the old habit of using diesel and suggests buying a cleaner from your asphalt plant.
Meter the flow. Chain the tailgate so it opens only 4 to 6 in, raise the bed slowly, and fill the box about halfway so the peak of the mix is level with the rear side plates.
Warm the screed. Pull forward about 12 in, then stop for 2 to 3 minutes so the hot mix heats the screed. A warm screed leaves a smoother surface.
Pull slow and steady. Long, even pulls at one consistent speed, keeping the box full but not overflowing, with mix spread evenly side to side so there are no bare spots. You cannot back up with the box on the ground, so start at the far end and work toward the exit.
Change depth gradually. If thickness needs adjusting mid-pull, turn the jacks a little at a time while moving so no ridge shows.

For parking lots and other wide areas, the manual suggests riding one skid up onto the edge of the previous strip with that side set to 0 in, so each new pass matches the last one's edge and height. The same trick widens a road. The truck drives on the existing pavement with that side at zero, while the other side, set up to 2-1/2 ft wider, fills the new shoulder up to grade.

Because a box has no heated screed, the mix has to arrive hot and be placed right away. The manual puts it bluntly: every minute counts. Plan the haul with our guide to tons of asphalt in a dump truck so loads arrive one at a time instead of sitting and cooling.

How deep to set the screed

A box screed strikes off loose mix, and loose mix shrinks under the roller. The published guidance varies, which is exactly why you should test it on your own job:

Colorado Springs (Section 400). Hand-placed mix is left high by about 1/4 in for every inch of depth. For 3 in compacted, that means about 3-3/4 in loose.
J. Pyott's manual. Its worked setup says a 3 in finished layer takes fresh mix "nearly 5" inches thick, which is a much larger allowance.

The difference comes from the mix, its temperature, how much the box itself packs the mat, and the roller. Set the screed partway between the two on the first strip, roll it, and probe or core it to measure the real compacted thickness. Then adjust the jacks for the rest of the job. Our handwork vs paver tonnage article explains why thick edges and raked spots raise the ticket total.

Worked example: a 10 ft × 100 ft driveway

Illustrative numbers only. Use your own measurements and your plant's mix data.

Area. 10 ft × 100 ft = 1,000 sq ft. A 10 ft box covers it in a single 100 ft pull.
Compacted volume. At 2.5 in (0.208 ft), 1,000 × 0.208 = about 208 cubic feet.
Tons. At 145 lb per cubic foot (the compacted planning density our calculator uses), 208 × 145 = about 30,200 lb, or 15.1 tons. Add about 5 percent for flares, edges and leftover mix and order about 16 tons. Check it with the how many tons of asphalt calculator.
Screed setting. Using the Colorado Springs allowance, 2.5 in × 1.25 = about 3-1/8 in loose. The Drag-A-Box example's ratio (5 ÷ 3) would put it closer to 4-1/8 in. Start near 3-1/2 in on the first 20 ft, roll it, measure, and adjust.
Loads. If the plant puts about 8 tons on each tandem (an assumption, so ask what they actually load), that is two trucks. Leave the box full of the first load's mix while the second truck backs in, which the manual recommends so there is no gap in the mat.

With a box, temperature limits the job more than machine speed does. Have the roller on site and running before the first load arrives.

Compaction and finishing behind the box

The box only places the mix, so density comes entirely from rolling. Colorado Springs' patching section, which permits either hand placement or "a spreader box without separation of the mixture" on small patches, requires rolling to 95 percent of maximum density (per AASHTO T 209). Rolling continues until roller marks disappear, and the finished patch is checked with a straightedge or stringline.

Edges and seams. One or two rakers with a lute fix bare spots, square the edges and clean up spillage. A 36 in magnesium lute such as the Kraft Tool GG836-6 asphalt lute with 6 ft handle is the usual tool. Our asphalt lute guide covers technique.
Corners the roller can't reach. A cast-steel hand tamper like the Truper 8x8-inch tamper handles garage lips, around utility boxes and along walls.
Temperature. Check the mix in the box and on the mat before you start and again before rolling. An industrial infrared gun such as the Fluke 62 Max (rated to 932°F) gives a quick surface reading.
Roller. A small tandem vibratory roller is the usual partner for a box. See our asphalt roller rental guide for sizes.

Where public specs allow a spreader box

Small patches and trench repairs. Colorado Springs allows a box or hand placement on small patches but calls for a self-propelled paver on large patches "whenever possible."
Leveling courses. Florida DOT's 2026-27 off-system (LAP) Section 334 allows leveling with a paver or with two motor graders, one carrying a spreader box. Georgia DOT's training manual likewise lists a motor grader with a spreader box and smooth tires for leveling courses.
Main lifts on state work. These generally require a paving machine. Florida's same section limits hand work to "limited areas where the use of the paver is impossible or impracticable." Read a box job's contract spec before assuming a box is acceptable.

When a spreader box makes sense

A box fits work too big to rake by hand but too small or remote to justify a paver: single driveways, farm lanes, trench patches, shoulder wedges, and small crews that already own dump trucks. It is a poor fit for large lots or anything held to a ride-quality spec, where a paver's heated screed and grade controls give a more uniform mat.

Asphalt spreader box FAQ

What is an asphalt spreader box?

A bottomless steel box with an adjustable rear strike-off edge. It is towed by a dump truck or pushed by a loader, and it lays hot mix at a set loose depth without the heated screed, augers or conveyors of a paver.

How thick can a spreader box lay asphalt?

It depends on the model. J. Pyott's Drag-A-Box CE 7-12 adjusts from 0 to 8 in and Melecio's paver boxes from 0 to 6 in, while skid steer spreaders such as Bobcat's and the Simex ST line lay up to about 4 in. Those are loose depths before rolling.

How much higher should I set the screed for rolldown?

Published guidance varies. Colorado Springs' spec leaves hand-placed mix about 1/4 in high per inch of depth, while the Drag-A-Box manual's example uses nearly 5 in loose for 3 in finished. Roll a test strip, measure it and adjust.

Can a skid steer pull an asphalt spreader box?

Yes. Some drag boxes take a skid steer or tractor hitch, and there are dedicated hydraulic skid steer spreaders. Check the attachment's weight and hydraulic flow (Simex lists 12 gpm at 2,900 psi) against your loader.

The bottom line

An asphalt spreader box is a low-cost strike-off tool: tow-behind boxes run about 7 to 12 ft wide and adjust from 0 to 6 or 8 in loose depth, and skid steer spreaders lay up to 4 in over narrower widths. Set the screed high enough for rolldown, confirm it on a test strip, keep the box full and the pulls steady, and have the roller and rakers ready, because nothing in the box keeps the mix hot.

Sources

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