Replace or Resurface a Madison Asphalt Driveway

Most driveway quotes in Madison fork at one question: can the existing base carry a new layer, or does it have to come out? Get that wrong in one direction and a new overlay cracks along the old lines; get it wrong in the other and a sound base is dug up and hauled away for nothing. This guide borrows the method public works departments use for streets, a visual rating on a 1-to-10 scale, and applies it to a single driveway.

The method has local roots. PASER, short for Pavement Surface Evaluation and Rating, was produced by the Transportation Information Center at UW-Madison, and the City of Madison rates every one of its streets every two years to decide which get resurfaced. The sections below cover why local pavement fails, how to rate a drive, what each band of scores means, and how Madison's soils, weather and permit calendar shape the choice.

Why Madison streets and driveways fail the same way

Asphalt around Madison wears out from two directions. From above, weather and age harden the binder, and the surface ravels as fine aggregate lets go. From below, frost and water attack the base. NOAA's normals for the airport station record about 87 days a year when the temperature crosses the freezing line, and Wisconsin's local-roads program describes the spring thaw, generally early March to early May, as the time when meltwater trapped above frozen ground saturates the base and strips it of strength.

Surface aging can be treated from the top. Base failure cannot, because it lives under the asphalt. The replace-or-resurface decision comes down to telling the two apart, and a rating scale does that by reading the pattern of cracks and deformation on the surface. The City of Madison uses its ratings the same way: streets scoring 5 or lower out of 10 go on the resurfacing list, where the old surface is milled or pulverized and repaved, while very poor pavement is one of the criteria for full reconstruction.

Rating a driveway on the 1-to-10 scale

Rate on a dry day in spring, after the thaw, when base problems are easiest to see. Walk the whole surface, including the edges and the apron, and look for the worst pattern that covers a meaningful share of the drive rather than one bad corner. The PASER manual's descriptions for asphalt translate directly to a driveway, as listed below.

Score the driveway by the lowest rating whose description fits a substantial area, then note where the worst spots are. A drive that is a 6 overall with one soft corner is an overlay with a patch. A drive that is a 3 in the wheel paths and a 6 at the edges is still a structural problem, because the wheel paths are where the load goes.

• 10 and 9: new or recently overlaid, no visible distress
• 8: no cracks except reflection of paving joints
• 7: longitudinal cracks about a quarter inch open, mostly at joints
• 6: slight raveling and traffic wear
• 5: moderate to severe raveling, loss of fine and coarse aggregate
• 4: severe raveling plus multiple longitudinal and transverse cracks
• 3: closely spaced cracking in both directions, often with raveling
• 2: alligator cracking over more than 25 percent of the surface
• 1: severe distress with extensive loss of surface integrity

Scores of 4 to 6: when an overlay earns its keep

In the middle band the surface is worn but the base is doing its job. The PASER manual treats a 5 as needing a preservative treatment such as a seal coat or overlay, and a 4 as needing structural improvement, generally an overlay. For a driveway that means cleaning, cutting out and replacing any isolated soft spots full depth, filling cracks, applying tack and paving a new layer. The resurfacing page covers the method.

Height is the practical limit. The Wisconsin Asphalt Pavement Association's minimum lift is 1.25 inches for a 9.5-millimeter mix and 1.75 inches for a 12.5-millimeter mix, so an overlay raises the surface at least that much. The garage slab, the public sidewalk and the terrace apron do not move, so the new layer has to be milled in flush at those edges, and a drive already overlaid once may need its whole surface milled before the next layer goes on.

Existing cracks are the other risk. They move with temperature and frost and tend to reflect up through the new layer, the reflection cracks the PASER manual describes at old joints. Filling them first and replacing the worst sections slows that down. An overlay in this band usually costs well under a replacement, and the cost page shows the ranges side by side.

Scores of 1 to 3: when the base has to be rebuilt

At 3 and below the cracking pattern says the structure has failed. At 3 the PASER manual calls for a structural overlay at least 2 inches thick, usually with milling and patching first, and reconstruction at 2 and 1, where alligator cracking covers more than a quarter of the surface. A driveway is small enough that, at a 3 with soft spots, full replacement is usually the better comparison to price.

Replacement is a chance to build the base for the ground. Silt loams formed in loess, such as Dodge, whose official type location is a Dane County site northeast of Sun Prairie, are the kind of fine-grained subgrade that WAPA's 2021 design guide rates as poor support. Its recommendation for a home driveway on poor soil is 4 inches of asphalt over 9 to 12 inches of base, against 3 inches over 6 to 8 on good sand or gravel. Grading and base repair covers the work under the new surface.

Rebuilding also resets the grades. If years of overlays have left the drive above the garage floor or pitched water toward the house, replacement is the time to fix the slope, to at least the 2 percent cross slope WAPA uses as a minimum on crowned surfaces.

Timing the decision around Madison's calendar

The rating and the paving happen in different seasons. The thaw that reveals base problems runs from early March to early May, and NOAA's April normal low at the airport is 35.8 degrees, below the 40 degrees the City's specifications set as the floor for placing surface asphalt. A driveway rated in April is realistically paved from May onward, and the most reliable paving temperatures last through September.

Permits add lead time when the apron is involved. The City's Street Terrace Permit is reviewed in 5 to 7 working days, the contractor must be prequalified for right-of-way work, and the apron and approach rules limit how wide the entrance can be. A street on the City's resurfacing or reconstruction list is worth checking before an apron is replaced, since the curb line may change.

The City aims for 30 or more years between resurfacing a street and rebuilding it. A private driveway sees far less traffic than a street, but the same principle holds: a well-timed overlay on a sound base buys years, and an overlay on a failed base buys very few.