How To Fix a Sinking Driveway

It’s normal for asphalt driveways to sink a bit over time. But when your driveway repair has sunk to the point where it’s 4 or 5 in. lower than your garage floor, it’s time to fix it. If you don’t, water will pool in the depression, seep into the soil below, and eventually destroy the driveway.

Asphalt companies charge about $1,000 to dig out the old portion and install a new apron. Concrete contractors charge even more. But you can rebuild your asphalt driveway apron yourself. The entire job takes a full day and it’s not much fun. However, the materials and tools only cost about $250, so the savings are worth it. Learn how to pour a concrete apron.

You’ll need a diamond blade for your circular saw, a tamper, a pry bar and a short square-blade shovel. Plus, you’ll need enough cold patch material to fill in the trench you make (sold at home centers). To figure out how many bags you’ll need, refer to the depth and width tables on the bag. Finally, you’ll need mineral spirits and rags for cleanup.

Cold patch cures by solvent evaporation, and it takes about 30 days to reach a full cure. The best time to do the project is during an extended warm, dry spell. You can do it in spring or fall, but cold weather and rain will greatly extend the cure time.

This driveway repair is a messy job, and no matter how careful you are, you’re going to get tar on your clothes and shoes. You can’t wash off the tar with soap and water. So wear old clothes and shoes that you can toss into the trash when you’re done. If you have to go into the house during the project, leave your shoes outside so you don’t track tar into the house.

Cut Out the Sunken Asphalt

Slap a diamond blade into your circular saw and set it to its maximum cutting depth. Then, snap a chalk line out from the garage floor to a maximum distance of 24 in. Wear an N95 respirator and safety glasses and cut out the old asphalt.

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Put in the Bottom Layer

Pour in a small amount of cold patch material and level it with a square-blade shovel. Tamp down a test section and measure the depth. The bottom layer should only be 1/2 in. thick when compacted. Add or remove cold patch material and then tamp down the entire starter row.

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Build Additional Layers

Add and compact the cold patch in 1-in. layers until you reach the garage floor. Then overfill with an additional 1/2 in. of material and tamp to get a smooth surface.

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Drive Over It to Compact

Cut a piece of plywood slightly wider than the trench. Lay it over the patch material and cover it with 2x4s. Then drive over it several times with your vehicle until the patch is level with the garage floor.

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Pavers Are Another Option

Another approach to fixing a sunken driveway is to make an apron from paving brick. It’s attractive, you can do it yourself, and you can easily reset the pavers if the soil settles again. Follow these steps:

1. Snap a chalk line parallel to the garage door. Make sure it’s out far enough to include all the settled asphalt. Lay out a row of your paving bricks, starting against the garage floor slab to position the chalk line at a full brick.
2. Cut through the asphalt (it’s usually 2 to 3 in. thick) along the chalk line. Be sure to wear hearing and eye protection.
3. Remove the asphalt and dig a 12-in. deep trench. Angle the wall of the trench slightly under the remaining asphalt. Rent a plate compactor and run it along the trench at least four times to compact the soil. Line the sides and bottom of the trench with landscape fabric. It’s available from landscape suppliers.
4. Spread a 2-in. layer of Class V or other compactable gravel, dampen it and run the compactor over it four times. Continue to spread and compact the gravel in 2-in. layers until it’s 3 in. below the existing driveway.
5. Install paver edging along grass edges and spread a 1-in. layer of coarse sand. Don’t compact it.
   Set your pavers, compact them with the plate compactor and fill the joints with sand. Be sure to use a joint stabilizing sealer to keep the sand from washing out.

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