Monday, February 25, 2013

Using a Concrete Edger

I poured another set of curbs for a new fence I'm building along the east side of our property.  Using an edger to put rounded corners on a concrete job is the easiest thing to make it look professional.  The key is to wait until the proper time to use it.  Too soon and the shape doesn't hold, too late and it's very difficult to work.

Basically, I fill the forms, level them off and then float them with a metal trowel, then go away for a while.  The amount of time depends on the temperature.  It was about 45˚F when I did this job, so I waited about 50 minutes and it was still plenty soft and workable.  In the summer, it might be less.  Usually about 15 minutes after you pour and screed and whatever you do initially, there's some water that bleeds up out of the concrete.  Don't touch anything while this is present.  Wait until it soaks back in, then give it a few more minutes.  If you start the process and the surface is still really soft, you can always come back later.  You want the consistency to be a little softer than modeling clay.

Start by digging in with the trailing corner to define the edge of the concrete

I use an edger in two steps.  First, I hold it up at an angle and drag it against the form to define the outer edge of the curb and create a track for the tool to follow in the next step.  Then I lay it down and use it to float and shape the surface.  Just apply light pressure and slightly lift the leading edge of the tool.  It's really pretty easy.  If the concrete is still pretty fresh, you can float up a lot of water and make the surface soupy.  Stop and come back in a few minutes if this happens.  Just work it until the shape is defined - and stop, or the cured surface will wind up weak and crumbly.  If you want to float it really smooth, come back when it's firmed up a bit more and give it a final pass.
Then lay the edger down to form and float the surface