How to Repair Cobblestone Driveways How to Repair Cobblestone Driveways

What You'll Need
Screwdriver
Replacement cobblestone
Short level
Sand
Shovel
Gravel
Concrete Sand
Plate compactor
TSP (tri-sodium phosphate)
Power washer

Cobblestone driveways are one of the most durable surfaces for a driveway. They can be expected to last for decades. There is little repair or maintenance required, but when there is a problem, you can generally remove the stones and repair just that area. There are a few problems that you can solve yourself.

Cracked or Broken Stones

If there are a few cracked or broken cobblestones in the driveway, you can replace them individually. Check for broken stones especially after very cold weather or heavy use of the driveway.

Step 1 – Remove the Stone

Use a screwdriver to pry up the damaged stone. Check the surface underneath and add sand or gravel if it needs to be leveled.

Step 2 - Reinstall the Stone

Put the replacement stone in place. Check to be sure it is level with the surrounds stones. Then, sweep some sand into the cracks around it.

Sunken Areas

Areas of a cobblestone drive can become sunken in due to problems with the underlayment.  This can be a more extensive repair, depending on the size and depth of the area.

Step 1 – Remove the Stones

Remove all of the stones from the sunken area. Remove some stones in a perimeter around the area as well so that you can more easily level the edges. Inspect the underlying surface. Make sure there are no drainage problems.

Step 2 – Fill in the Area

Fill in the area with gravel. Wet it down thoroughly. Now add some concrete sand on top. Use the plate compactor or a hand tamper to level the area.

Step 3 – Reinstall the Stones

Now place the stones on the new base and fit them in tightly. Once the stones are laid, sweep in some new sand around them.

Discoloration

If the cobblestones have become unsightly by leaking auto fluids, algae or other kinds of discolorations, you can easily clean them.

Step 1 – Preparation

Mix water with the TSP (see the recommendations on the box) and load it into the power washer. Test the washer on a lower power setting and turn it up gradually until it removes the discoloration.

Step 2 –Wash

Now that you know the correct setting, turn on the power washer and go over the cobblestones. You may need to hold the nozzle at different angles to get all of the debris off of the cobblestones. Don’t forget to clean the curbs and driveway apron.

Step 3 – Rinse

Now fill the power washer with clean water and rinse the cobblestones thoroughly.

There are some problems that may require extensive repairs or help from a professional. If you have drainage or shifting soil problems, then these should be resolved be attempting to repair the driveway. To prevent any major issues from developing in the future, it is a good idea to walk the entire driveway several times a year looking for loose stones, areas that are out of level, and sweeping some new sand.

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