Recycled Asphalt Shingles for Driveways: Pros, Cons, Rules
The short answer
Ground-up roofing shingles can make a firm, low-dust surface on a gravel driveway, but only when they are handled the right way. The proven method is to blend the ground shingles into crushed stone, not to spread them on their own, and to buy them from a recycler that has removed the nails and tested the material for asbestos. The asphalt in the shingles works as a binder that holds the stone together and keeps dust down.
The catch is that the rules depend on where you live. Some states treat ground shingles as an approved road-surfacing material. Others restrict loose shingle uses because of what the material contains. So the first job is not choosing a rake; it is a phone call to the recycler and, if needed, your state environmental agency. This guide walks through what the research found, the risks, the rules, a worked quantity example and a step-by-step method.
What recycled asphalt shingles are
Recycled asphalt shingles, often shortened to RAS, are roofing shingles that have been ground into small pieces. Recyclers take in two kinds: factory scrap from shingle plants and tear-off shingles from old roofs. Minnesota's transportation research program describes both and estimates that the state alone produces more than 200,000 tons of shingle waste a year.
The reason anyone wants that waste on a road is the asphalt. An Iowa DOT research paper puts the asphalt binder content of bituminous shingles at about 30%. When ground shingles are mixed into crushed rock and packed by traffic, that binder glues the fine particles together the way a weak version of pavement would.
Most RAS goes into hot mix asphalt, but there is a limit to how much a mix can take. Minnesota's report notes that current practice keeps RAS in hot mix to no more than 5% by weight, which leaves plenty of ground shingles looking for another use. Unpaved roads and driveways are one of them. For the paving side of the story, see our guide to asphalt shingle recycling.
What the Iowa gravel road trial showed
The best-documented field test of shingles on an unpaved surface comes from Benton County, Iowa. In 1995 the county engineer decided to try ground tear-off shingles as dust control on a rural crushed stone road, and the Iowa DOT wrote it up in a 1997 interim report, Let Me Shingle Your Roadway (HR-2079). The details are worth knowing because they map well to a long rural driveway.
| Item | What the county did or found |
|---|---|
| Grinding | 900 tons of waste shingles ground with a Maxigrind tub grinder, mostly through a 2-inch (51 mm) screen. A 1-inch screen was tried but cut output to about 15 tons per hour. |
| Nails | A magnetic roller on the discharge conveyor pulled most nails. A magnet on the motor grader picked up about another 3/4 lb during spreading. |
| Product | About 82% shingle and 18% wood by dry weight, at 6.6% moisture. |
| Placement | 500 tons dumped on top of the existing crushed limestone and bladed back and forth. The goal was an equal volume of shingles and stone. The mixed layer was about 2.5 inches (65 mm) thick. |
| Dust | A DOT car at 50 mph raised no dust on the treated stretch, while the untreated road next to it was dusty. It stayed nearly dust free one and two years later. |
| Other effects | The surface could still be bladed like normal gravel. The report describes the road as smoother and quieter, with less stone lost to the ditches. |
| Problems | Light wood bits were pushed to the edges by traffic, the surface looked somewhat open by winter, and a few flat tires came from nails that were missed. |
In December 1995 the county sprayed a light fog seal of CSS-1 emulsion diluted with twice its volume of water, at about 0.3 gallon per square yard, to tighten the open surface.
Minnesota later ran its own study of shingles as a stabilizer and dust control for gravel roads and shoulders, framed as a possible stand-in for chloride treatments as good gravel sources ran short. The takeaway from both states is the same: shingles work best as an ingredient in a gravel surface, not as the whole surface.
Pros and cons for a home driveway
| Pros | Cons |
|---|---|
| Binds loose stone and cuts dust, based on the Iowa trial | Stray roofing nails can cause flat tires if the recycler's magnets miss them |
| Can still be graded or raked like regular gravel | Loose ground roofing can carry metals and PAHs; some states restrict these uses |
| Uses a material that would otherwise be landfilled | Old roofing can contain asbestos unless it has been tested |
| Often sold cheaply by recyclers | Wood, felt and plastic bits can show up and drift to the edges |
| Quieter, smoother ride than open gravel | Will not give you the clean, sealed look of a paved drive |
Safety and the rules: check before you spread
Asbestos. The Iowa report says asbestos was used in a small share of bituminous shingles made between 1940 and 1973, and that shingles made after 1973 are not an asbestos concern. Of 368 shingle samples Iowa DOT had tested since 1994, three contained asbestos, about 0.8%. The same report summarizes an EPA Region VII letter: shingles from homes with four or fewer dwelling units are exempt from the federal asbestos NESHAP rule, while shingles from larger buildings need sampling, and material with more than 1% asbestos cannot be used on roads. Ask the recycler how they screen loads.
Other contaminants. Washington's Department of Ecology tested ground asphalt roofing and reported metals, including arsenic, and PAHs at levels that may be harmful. Its concern is the loose form, where people can breathe or swallow particles and rain can wash them away. Ecology expects a recycler to hold a solid waste permit or a beneficial use determination before selling ground roofing for loose uses. It names unpaved home driveways among the uses that have been tried. Roofing bound in hot mix or cold patch is seen as lower risk and is not expected to need that approval.
State rules vary. Two examples show the range:
- Iowa pre-approves shingles certified at no more than 1% asbestos for road surfacing granular material, subbase and asphalt pavement, without further state approval (Iowa Administrative Code 567-102.303).
- Pennsylvania's general permit WMGR138 limits processed shingles to asphalt mix, subbase, fuel use and dust control on rural roads when applied with a binder. It also bars placement within 4 feet of the seasonal high water table or bedrock unless the state allows it.
If your state is not one of these, search its environmental agency site for "asphalt shingles beneficial use," or ask the recycler which approval they operate under. A recycler that sells to the public for driveways should be able to tell you.
Skip shingles near a private well, a garden or a pond, and do not use them where kids play. Keep pets from chewing the pieces. And never grind your own tear-off at home; that is how dust and nails end up where they should not be.
Worked example: how much to order
Say your gravel driveway is 12 feet wide and 150 feet long, and you want to copy the Iowa approach: blend shingles and stone in equal volumes into a layer about 2.5 inches thick. These numbers are an illustration, not a design.
| Step | Calculation | Result |
|---|---|---|
| Area | 12 ft × 150 ft | 1,800 sq ft |
| Blended layer volume | 1,800 × (2.5 ÷ 12) ft | 375 cu ft |
| Convert to cubic yards | 375 ÷ 27 | about 13.9 cu yd |
| Ground shingle share (half by volume) | 13.9 ÷ 2 | about 7 cu yd |
| Stone share | Existing surface stone, topped up if thin | about 7 cu yd |
Ground shingles are loose and will pack down, so order a little extra and ask the recycler what a yard of their product weighs if they sell by the ton; it varies with grind size, wood content and moisture. If the driveway is already short on stone, figure the top-up with our tonnage calculator or the gravel road maintenance guide, which covers crown and surface gravel.
How to add ground shingles to a gravel driveway
- Confirm the source. Buy from a recycler that removes nails and screens loads for asbestos, and ask which state approval covers driveway use.
- Fix drainage and crown first. Shingles will not save a driveway that holds water. Reshape the surface so it sheds water to the sides.
- Loosen the top of the stone. Scarify or rake the top inch or two so the shingles can mix in rather than sit on top.
- Spread and mix. Dump the shingles in windrows and blend them into the stone with a box blade or grader. On short drives, an aluminum landscape rake or a heavy bow rake does the job by hand.
- Pick up nails. Run a rolling magnetic sweeper over the surface after mixing, and again after the first few weeks of traffic.
- Compact. Wet the surface lightly and roll it, or let your vehicles pack it over a few warm weeks. Heat softens the binder and helps it set.
- Tidy the edges. Rake wood bits and stray pieces back in or bag them. A light fog seal, as Benton County used, is an option for a contractor on a long drive.
Do this on a dry, warm day, wear gloves and eye protection, and keep the material damp if it starts to dust.
Better options for some driveways
If your state restricts loose shingle uses, or you want a cleaner surface, a recycled asphalt millings driveway gives a similar bound, low-dust result using old pavement instead of roofing. Like shingles, millings rely on old asphalt binder to hold the surface together. For washboard trouble on plain gravel, start with our guide to the washboard gravel road, since crown and fines usually matter more than any additive.
Recycled asphalt shingles FAQ
Are ground-up shingles good for a driveway?
They can be when mixed into crushed stone. In an Iowa DOT field trial, ground shingles blended with crushed limestone kept a rural road nearly dust free for two years and made it smoother and quieter. Spread alone, they are loose and messy.
Do recycled shingles contain asbestos?
Rarely. Iowa DOT found asbestos in 3 of 368 shingle samples, about 0.8%, and says it shows up mainly in shingles made between 1940 and 1973. Buy from a recycler that screens loads for asbestos.
Is it legal to put ground shingles on my driveway?
It depends on the state. Iowa pre-approves certified shingles for road surfacing, Pennsylvania allows rural road dust control only with a binder, and Washington expects recyclers to get approval before selling ground roofing for loose uses. Check with your state environmental agency.
How thick should a shingle and gravel layer be?
The Iowa trial blended roughly equal volumes of ground shingles and crushed stone into a layer about 2.5 inches thick. Treat that as a starting point and adjust for your stone depth and traffic.
Will ground shingles cause flat tires?
They can if nails are left in. The Iowa trial reported a few flat tires from missed nails, so buy material that has gone through magnetic nail removal and sweep the surface with a magnet after spreading.
The bottom line
Recycled asphalt shingles can turn a dusty gravel driveway into a tighter, quieter surface, and an Iowa county showed it on a public road for at least two years. Treat them as a binder mixed into stone, buy only nail-free, asbestos-screened material, and check your state's rules first, because some agencies limit loose shingle uses over metals and PAHs. If that is a problem where you live, asphalt millings do much the same job.
Sources checked for this article
- Iowa DOT: Let Me Shingle Your Roadway, HR-2079 interim report (Marks and Petermeier, 1997)
- MnDOT / LRRB: Research Using Waste Shingles for Stabilization or Dust Control for Gravel Roads and Shoulders (MN/RC 2014-06)
- Washington Department of Ecology: Acceptable Uses for Recycled Asphalt Roofing in Washington State (09-07-074)
- Iowa Administrative Code 567-102.303: Universally approved beneficial use determinations
- Pennsylvania DEP: General Permit WMGR138, asphalt shingle use restrictions
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