Cracked Slab Repair
The concrete floor in our garage is cracked, probably a result of an earthquake. I'm thinking about cutting through it around its perimeter, breaking it up, and then pouring a new slab. Any advice to share?
—Maurice Patrykus, Santa Paula, Calif.
Tom Silva replies: If you are looking for a big, messy project, you sure found it. Sure, it's technically possible to cut out an existing slab, but it's not something you'll do in a day with a circular saw and a couple of masonry blades. First, you'd want an engineer to come in and make sure that removing the slab, even temporarily, won't weaken the existing garage foundation. Then you'd need a diamond-blade saw to slice through the slab, a demolition hammer to break it up, and some sort of a bucket loader and a dump truck to get rid of all the debris. Sound like fun?
I would say it's not worth ripping into it unless the crack is getting significantly worse. You can figure that out by taking careful measurements of its width over time with a special crack gauge. If it's not getting any wider, just patch it with some hydraulic cement. You'll be done in a couple of hours.