Sinking Brick Patio
Q: How do I fix a sinking brick patio?
Years ago, I laid a brick-on-sand patio. At the time, the brick was flush with the top of a 6-inch-diameter cast-iron pipe cleanout. Now the pipe sticks up about 2 inches above the brick. How can I fix this problem?
—C.J. Bosch, Woodcliff Lake, N.J.
Roger Cook replies: Two inches is a lot for a brick patio to sink, but if that's what's going on, the dip will be obvious when you lay a 4-foot level or metal straightedge across the area. Lift out the sunken bricks with a flat pry bar, add enough sand to bring them back to level, then tap them back into place with a rubber mallet.
Of course, it's possible that the bricks are fine and the pipe has lifted. Sometimes a length of pipe is slipped over another to provide extra stiffness, and the freeze-thaw cycle can push up the outer sleeve over time. To fix, remove the bricks around the pipe, dig a few inches, then have a plumber verify the situation. If he confirms that the pipe is sleeved, tap it down using a scrap of 2x4 and a 3-pound hammer. If you try to drive the pipe deeper and it's not a sleeve, you'll have an expensive repair project on your hands. When the pipe is back down where you want it, put back the sand and bricks.