Build a Concrete Walkway: Smoothing the Surface
Learn how to smooth the concrete surface for a polished finish with the use of bull floats, magnesium floats, trowels, and edging tools.
Video Transcript:
Whether you’re going to finish your walkway with a stamped or textured surface, you will want to get started as soon as the concrete has been poured into the form, and screeded flat.
In this episode, you’ll learn how to use a bull float to initially smooth the surface. Then you will go through the steps of using a magnesium float, a steel finishing trowel, and an edging tool to prep the surface for any finish you may want to add.
When using any type of trowel or float tool, it’s important to concentrate on keeping the leading edge tilted slight up to avoid digging into the fresh concrete. The first step is to use a bull float over the entire surface. A bull float is a large magnesium float that’s pushed and pulled over the surface using a pole that can be extended by screwing in additional sections. The purpose of the bull float is to flatten out the surface and push the small stone in the mix down. Move the handle either up or down to allow the float to skim across the surface. The magnesium bull float opens up the concrete allowing bleed water to bring up the fines of the mix, creating a creamy consistency on the top.
After bull floating, the surface should look flat and shiny, with perhaps a few lines from the side of the float. A helpful tip is to clean off your concrete tools immediately after every use. Dried, caked on concrete will ruin the working surface and is extremely difficult to remove.
Depending on the mix, you may see quite a bit of bleed water coming to the surface. That’s fine, but you have to wait until that water is gone before moving on to the next step. On a hot day, it may take only five or ten minutes between steps; on cold days you may be waiting an hour or more.
Once the bleed water is gone and the concrete has set enough so that your boot leaves about a ¼ inch depression when you step on the surface, it’s time to get busy. With a hand-held mag float, work the edges to drop more cream, and then follow with the edging tool. The edger rounds the sharp edge of the walkway with a radius of about ½ inch. The eased edge will create a finished look and is less prone to chipping. For best results, keep the edger flat on the surface.
The final tool used at this stage is a large steel trowel or a finish trowel. It’s easier to use a trowel that has at least two curved corners to help it from digging in. The purpose of the steel trowel is to close up the concrete by forcing the cream back down into the surface. This helps to create a hard, smooth, durable finish. Use wide sweeping arcs that overlap slightly. If there are areas that seem too dry, just hit them again with the mag float. Once you’ve finished with the steel trowel, you’re ready for stamping.
