This can take 20 minutes or 4 hours depending on the temperature, humidity and how hard the wind is blowing.
When should I float my concrete slab?
Float the concrete when you're done grooving and edging (Photo 6). Floating removes the marks left by edging and brings the surface one step closer to a final finish. You may have to bear down on the float if the concrete is starting to harden.
When can I power float concrete?
A rough guide for considering when to begin power floating is when walking on the surface leaves indentations of 3-4 mm . If the concrete is too wet the machine will tear up the surface, and if it is too dry, it will not be possible to trim high spots or fill low spots effectively.
Can you float concrete the next day?
Wait for the water to completely drain back in before working any further on the slab. If you begin using a float too soon, you could sweep some of the water off the slab before it has a chance to be re-absorbed. Reducing the water content will weaken the surface of the concrete.
When should I start bull floating concrete?
Bull floating is performed on freshly poured concrete during the initial finishing process before surface water , called bleed water, appears. Floating with a hand or power float, is a final finishing procedure performed after the bleed water has dried.
How long should concrete cure before putting weight on it?
Your concrete should be solid enough to walk on, without leaving footprints, after anything from 24 to 48 hours. By seven days , your concrete should be cured to at least 70 percent of its full strength.
How long should concrete cure before removing forms?
Walls and columns can be removed after about 24-48 hours . Slabs, with their props left under them, can typically be removed after 3-4 days.
When should I start watering my concrete?
Be sure to start watering the concrete in the morning and keep watering throughout the hottest part of the day. Do not start watering during the hottest part of the day because it could shock the concrete into developing surface crazing (similar to a hot glass breaking when filled with cold water).
What to do if it rains after pouring concrete?
Tips for Handling Rain After Pouring Concrete
Don't broadcast dry cement onto the concrete to soak up surface water. This will impair the finish and further weaken the top layer. Instead, once the rain passes, use a float to push the water off the edge of the slab before you start finishing .
Do you need to float concrete?
Floating has to be done on virtually every concrete job after concrete is poured and leveled . ... When done properly, floating pushes the aggregate down into the concrete and encourages moisture to rise, helping the concrete dry and creating a smoother surface.
Can you over work concrete?
Never overwork or over finish the surface of any exposed concrete slab. This brings too much fine material to the surface, works out the designed air entrainment*, and will weaken the surface of the slab leaving the top of slab more vulnerable to freeze/thaw damage and sheet scaling*.
Why do you power float concrete?
A power float is a hand-operated machine used to produce a smooth, dense and level surface finish to insitu concrete beds . Power floating eliminates the time and materials needed to apply a finishing screed and is quicker and less labour-intensive process than hand trowelling.
How long should concrete be before edging?
Step 1 – Wait Until the Cement is Almost Dry
Before you begin to edge the concrete slab, you should wait until it starts to dry and harden. When you start edging, the cement should be slightly firm but still pliable and able to be worked with the edger.
Why does magnesium float on concrete?
Magnesium smooths the surface of fresh concrete and opens the pores for proper evaporation , all without pulling the surface like a wood or resin tool. ... Extruded floats are made by pushing molten magnesium through a die (think Play-Doh), so the floats are the same profile from end to end.
What can I use instead of a bull float?
Fresnos are used for troweling slabs that do not require a hard trowel surface. A Fresnos will speed up the troweling process. Fresnos should not be used as bull floats. Troweling can also be accomplished by machine.
What is Devil float?
[′dev·əl ‚flōt] (engineering) A hand float containing nails projecting at each corner and used to roughen the surface of plaster to provide a key for the next coat . Also known as devil; nail coat.
