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How to Fix a Sinking Driveway Drainage System

Mason Mark McCullough helps a homeowner handle a sinking drywell forming a major depression in their driveway.

Mark McCullough helps a homeowner with a driveway repair. The homeowner has a drywell in the middle of their driveway, and while it’s still draining well, it’s beginning to sink. After checking out the grade around the drain, Mark and the homeowner dig out the well to see what’s happening.

Steps for Fixing a Sinking Drywell

  1. Start by removing the grate from the drain and removing all of the debris. Be sure to remove leaves, dirt, and other sediment out of the way.
  2. Next, remove the grate frame or ring from under the asphalt. Put on a pair of safety glasses and use the hammer and masonry chisel to cut away at the asphalt around the ring, removing approximately 6 inches of asphalt around the drain. Once the lip on the bottom of the frame is exposed, lift it out of the hole.
  3. Inspect the grate setting for failure by removing the loose asphalt and dirt with a masonry trowel. Remove any broken or deteriorated bricks, as well as all of the damaged asphalt. Clean the hole out again, giving it a rinse with a garden hose and nozzle.
  4. Rebuild the grate setting using new bricks and mortar. Mix the mortar according to the manufacturer’s instructions and lay a bed over the existing bricks. Set the new bricks into the mortar and tap them down with the butt of the masonry trowel. Be sure to stagger the joints between bricks and maintain a consistent height.
  5. Coat the bricks on the inside, outside, and top with mortar to add more strength to the setting.
  6. Place the grate frame on top of the setting. Stretch a string line from the asphalt on either side of the hole. Ensure that there is approximately 2 inches of space from the top of the frame to the string to allow for proper drainage without creating too much of a depression in the middle of the driveway. Build up with bricks and mortar if needed.
  7. Lay a bed of mortar around the outside of the grate frame to anchor it and help the existing asphalt to stay in place.
  8. Pour crushed stone around the outside of the ring and tamp it down with a brick.
  9. Fill around the grate ring with an asphalt patch, pressing and tamping it into place with the mason’s float. Use the float to smooth the asphalt, taper it toward the drain, and replace the grate. Allow the asphalt to set for around 2 weeks.


Mark raised a drywell in a driveway that sunk below grade. After using a chipping hammer and chisel to break away the sunken asphalt, Mark removed the grate and added gravel. He chose to use EZ Street ready-to-use asphalt and ProMasonry Type S Mortar mix to level out the drywell.

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