How To Repair An Asphalt Parking Lot Damaged By Tree Root Growth

Trees provide a lot of benefits, but they can also play havoc with paved surfaces. If your tree-lined, asphalt-paved, parking area has developed a large crack and shows signs of mounding, it's likely a tree root has forced the pavement upward. Below is how you can remove an offending tree root and repair the asphalt surface:

Tools and materials needed

  • Circular saw with continuous diamond blade suitable for dry cutting

  • Crushed stone dust

  • Cold-mix asphalt patching material

  • Asphalt sealer

  • Tamper

  • Shovel

  • Pry bar

  • Masonry chisel

  • 3-pound sledge hammer

  • Pruning saw

  • Straightedge

  • Squeegee mop

  • Chalk

  • Eye protection

  • Hearing protection

  • Gloves

Step-by-step procedure

1. Mark and cut asphalt - Before beginning, be sure to wear eye and hearing protection when using the saw to cut asphalt; it's loud, and the saw can kick asphalt chips into your eyes at high speeds.

Determine where you want to cut by measuring at least one foot on either side of the crack and marking a chalk outline with a straightedge. You can increase the distance from the crack as the mounding around the crack grows in height.

After determining your cut lines, start the circular saw and allow the blade to turn freely until it reaches full speed. Next, carefully and slowly lower the running saw blade into the surface of the asphalt along the cut line. If the blade binds badly, immediately pull it out of the asphalt and start again. Allow the blade to penetrate about two inches into the asphalt and slowly move it along the cut line; if you smell burning or see smoke, remove the saw and allow the blade to cool for a few seconds before resuming.

2. Pull up the asphalt - Once you have cut all along the lines, use a shovel and a pry bar, if necessary, to pull up the chunks of asphalt. You may need to use a masonry chisel and small sledge hammer to break through stubborn fragments of asphalt. Try to make your edges as clean as possible so they will make a neater appearance when patched.

3. Dig to the root and remove it - After the asphalt is out of the way, use a shovel to dig to the tree root. Clear away all the surrounding soil so the root is exposed on top and the sides. When you have a clear view of the root, cut it all the way through using your pruning saw so that none of it protrudes beneath the parking area. You may need to cut the root in smaller segments to make easier removal. Remove as much root material as possible, but don't worry about pulling up smaller root sections that might exist underneath the parking lot. Once the main section is cut, these smaller pieces will no longer pose a threat.

4. Prepare a base for the asphalt patch - After removing all the visible and easily-accessed roots, pour crushed stone dust into the area where the asphalt was removed. Use a tamper to pack the dust into the soil, and alternate pouring dust with tamping to achieve a uniformly packed surface. Continue adding dust and tamping until its level is equal to the bottom of the adjacent layers of asphalt.

5. Pour the asphalt patch - When you have prepared a strong, level base with the stone dust, add cold-mix asphalt patch material to the top of the base. Again, pour asphalt and alternate using the tamper to pack the material firmly. Continue adding and tamping the asphalt until the layer is slightly above the surrounding asphalt; the purpose for adding a little more asphalt is to provide room for settling due to vehicle traffic and the effects of moisture.

6. Seal the asphalt - Once the asphalt patch is in place, allow the asphalt to cure for at least 30 days before applying a sealer. Use a squeegee mop to apply a coat of asphalt sealer on top of the asphalt to protect it from water penetration. If necessary, apply a second coat of sealer to ensure the repair maintains its integrity.

If your parking lot has too many problems, click here to continue reading about the services a professional can provide.