Q: Our home was built in 1927 on a flat lot in Alameda, Calif. We bought the property in 1960 and had flooding in the garage in the winter because of the slope of the patio toward the back door of the garage.
Several years ago we had an aluminum box installed at the door opening inside the garage with a pipe set at an angle to carry the water away from the garage. This eliminated the flooding in the garage, but we still have a puddle in front of the door when it rains.
How can we eliminate this problem?
A: We have a couple of ideas for getting rid of the puddle.
You could install a floor drain from the low point of the concrete to channel water into the aluminum box installed inside your garage.
The other option is to level the low spot in the walkway with vinyl concrete leveling compound, which will eliminate the dip where water collects.
Neither solution is pricey, but installing a new pipe is more work than leveling out the dip in the walkway. Leveling the dip will get rid of the puddle. But that water will go somewhere–maybe not where you want it to go.
The aluminum box that is installed inside your garage door is a drywell. A drywell is a hole in the ground where water collects. The pipe installed in the box channels the water away from the box. This is similar to a septic tank and leach lines. The pipe is probably drainpipe that is perforated with holes. This allows the water to percolate into the soil. Alameda, Calif., has very sandy soil, which allows the water to percolate easily into the ground.
INSTALLING A DRAIN
The diagram you provided shows that the distance from the puddle to the box is only a few feet. We suggest you install a floor drain with a 3-inch polyvinyl chloride pipe (PVC) running from the low point of the sidewalk into the drywell.
To extend a pipe from the walkway into the box, you’ll have to cut and chip out a bit of concrete.
To cut the concrete, attach a diamond-studded blade to a circular saw. Cut parallel lines about 8 inches apart from the low point in the concrete toward the box. Make the cuts about 1 1/2 inches deep. Stop the cuts at the threshold of the garage door.
Then, with a hammer and a cold chisel, chip out the concrete and dig a shallow trench, 6 inches or so deep, to the box. Cut a hole in the aluminum box for the pipe to enter the drywell.
Glue a floor drain to a 90-degree sweep elbow and extend a piece of PVC from the other end of the elbow into the box. To prevent dirt from leaching into the box, seal the opening around the pipe with plumber’s putty. Backfill the hole, making sure to tamp the soil firmly.
Then cover the drain with tape to prevent concrete from entering the pipe when you replace the concrete over the trench. Mix and pour enough Redi-Mix concrete to cover the trench. Smooth the concrete with a steel trowel.
LEVELING THE WALKWAY
An alternative to installing a drain is to flatten out the low spot with a vinyl concrete compound especially made for leveling concrete. This product is available at home centers and at well-stocked hardware stores. You’ll need the leveling compound, concrete adhesive and a wood float.
The material must be applied to a clean surface. Wet the area, scrub it with a stiff brush and allow the surface to dry. Using adhesive is necessary to ensure a stable bond between the old concrete and the patch.
Apply the adhesive to the low spot according to manufacturer’s instructions. Finish by mixing the leveling compound and float it into the depression, making sure to finish it even with the surrounding area.
Because applying leveling compound is quick and inexpensive, we suggest you try this route first. If that doesn’t work to your satisfaction, try installing the drain.
