Concrete patios, driveways and paths have to be sloped to promote good drainage, and I’ve poured more sloped concrete than I care to recall. The challenge with this kind of work is getting the levels right, and that means installing plenty of elevation stakes. But elevation stakes can be tough to drive into rocky soil or dry-clay soil. The stake ends up split or burred. And to make matters worse, wood stakes are easily lost in the excitement that often accompanies a concrete pour.
On my last sloped slab, I used stakes made of 1/2-in. copper water pipe. Not only were they easy to drive into the hard ground, but they were also equally easy to see as I raked the concrete and screeded it to its final elevation. Each pipe stood out as a perfect, dime-sized black spot against the light-gray concrete. Evidently the 1/2-in. dia. hole is too small for the average piece of aggregate to clog, and the concrete cream doesn’t have the viscosity necessary to span the hole. As soon as the concrete has been screeded to its final elevation, you can either pull out the stakes or drive them with a length of pipe beyond the bottom of the slab.
Tony Toccalino, Milton, None
