We trowel concrete in coastal California with Mediterranean conditions in one area or hot and dry conditions in another. Here’s some information for your regional variance trivia file.

  • The pace: ten yards every 30 minutes for 4-inch slabs or every 20 minutes for 6-inch slabs.
  • Typical mix: 4-inch slump with a high range five or six sack blend mix. Blend means we add some 3/8-inch bin materials along with the sand and the ¾-inch bin materials. We try to include at least 10% fly ash.
  • Air: We don’t have freezing here so we have to watch the ready-mix company that will air to get a slump (and volume) increase, due to fear of blistering and delamination.
  • Concrete delivery is the earliest loads--we never go on second round and never on Monday.
  • Placing: We vibrate with a potato head.
  • Screeding: We use a wood 2x4 screed in a siding/wiping with a final lifting and rotating motion to shape the concrete and throw back to fill holes. Sometimes we use a weed whacker screed on pipe rails, never on a wet screed edge (consider not flat enough).
  • Floating: If we can float as we go, that is desirable but sometimes not enough crew on smaller placements. Hand rodding is sometimes followed by one slow pass with a single drum roller tamp, then floated with the wood. We float initially with a big wood float (3-foot or 4-foot) and edges are worked with a wood float or a phenolic. The only steel on the slab is a single pass with an edger to push rocks at the form side - but the use of this tool early typically causes the slab edge to pillow or round over and lose the profile, so we have been encouraging/requiring a margin trowel to dice the formed edge and hold off on the edger.
  • More floating: As the concrete shrinks, more wood floating passes are added. The concrete begins to lose the bleed water and then the magnesium float is used.
  • Troweling: If we run a power trowel, only wood tools on the slab. If we use pans, they are on walkers and we use a channel float if we want it to be flatter. Our rider on the float blades loves that channel floated surface. If it is hot or windy, we spray evaporation retarder after every float or trowel pass—especially if the mix has silica fume or extra additives.
  • Final pass: The fresno without weights and then with the weights is last. A good pass with a fresno leaves a slight appearance of an orange peel, but ever so slight. Our biggest fresno is 3-foot but a 2-foot is sometimes better. No 4-foot fresnos. Maybe a pass or two with burn trowels and kneeboards. If it is broomed, we may or may not skip the kneeboard step. And don't forget the infamous funny trowel which comes in handy for wrapping up and erasing trowel and extraneous marks, like where hand troweled edge meets power trowel. A funny trowel is so much better with a tapered wood handle.
  • And we always have a small sprayer with Fritz-Pak control finish ready to go.
  • Saw-cuts: In the Mediterranean conditions, we seldom can early entry saw cut during the work day as the edges of the cut chips a little too much, so the saw folks simply have to stay later. They usually have cleanup chores to do while they are waiting.