Question: Do You Need To Float Concrete?

What is the difference between a trowel and a float?

A float has a thicker base than a trowel and is usually made of plastic, sponge, rubber, wood or magnesium – a lightweight pale grey metal.

It’s used to even up the surface on plaster or concrete, make it firmer and give whatever texture is required..

Why do you float concrete?

Floating has to be done on virtually every concrete job after concrete is poured and leveled. (Leveling is usually accomplished with a screed.) 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.

How do you smooth concrete after it dries?

These are the 4 steps in how to smooth concrete after it dries:Remove all imperfections on the surface.Vacuum up all debris and apply the adherent.Apply a new layer of concrete.Sand the surface and wash the concrete.Apply a layer of vitrifier to protect the concrete.Aug 27, 2020

What is the difference between a Fresno and a bull float?

A fresno is a large, long-handled trowel that looks similar to a bull float, except the blade is made of tempered or “blue” steel. … In fact, most manufacturers refer to a fresno as a fresno trowel. Just like a steel trowel, only use a fresno after the surface has been floated with a wood or magnesium float.

Do you have to float concrete?

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.

What does a magnesium float do to 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. Most magnesium floats are extruded or cast. … Molten magnesium can be cast into any shape desired.

Should I put plastic under concrete?

Recently, though, research has shown that the old traditional layer of 6-mil Visqueen (polyethylene plastic) under the slab is seldom effective for two main reasons: Although it may seem water-tight, this grade of material allows a lot of water vapor to pass through.

What defects can be caused by bull floating too soon?

More often, premature finishing or improper first (bull floating) or second floating results in trapping rising bleed water and air below the top surface of the concrete (Image 2). When this occurs, the resulting weak or soft zone below the surface causes the top surface of the concrete to flake or scale off.

Can you finish concrete without 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.

Can magnesium float on water?

Magnesium hydroxide separates the magnesium surface with water in hot air and further reaction of magnesium stops reacting with water. … Therefore magnesium ribbon does not sink and floats on water.

Do you have to use a bull float on concrete?

After pouring the concrete and screeding it level, the bull float is the first tool we use when finishing the slab. The job must be done right after screeding because the concrete will still be wet enough to shape. … This keeps the surface smooth without digging the magnesium board into the concrete by accident.

What is the purpose of troweling concrete?

Purpose: Used after floating to produce a smooth, hard, dense slab surface.

How long should concrete set before removing forms?

The forms or “molding” that holds the concrete in place until it dries should be left alone for at least two days to ensure that the concrete is completely dry. If the forms are removed too soon, the concrete can begin to sag, crack and collapse, especially if conditions like temperature affected its strength.

How long do you wait to bull float concrete?

Darbying or bull floating should be done immediately after “screeding”, or after the concrete has been tamped if tamping was done. This process should be finished before excess moisture or bleedwater appear on the surface.

What tool do you use to smooth concrete?

Screeds are long, straight, stiff tubing or boards used to smooth and roughly level wet concrete shortly after it is poured. Screeds are available in different sizes and can even be project-specific, such as those used for building concrete bridges.

How long do you wait to float concrete?

Allow all of the water to disappear before you do anything else. This can take 20 minutes or 4 hours depending on the temperature, humidity and how hard the wind is blowing. After the bleed water is all gone, you can get out your steel finishing trowel and put on the final touches.

Can you pour concrete directly on dirt?

Long story short, yes you can pour concrete over dirt.

Is gravel necessary under concrete?

Whether you pour concrete for a walkway or patio, a strong gravel base is required to prevent the concrete from cracking and shifting. Gravel is especially important in clay soil because it doesn’t drain well, which results in water pooling under the concrete slab and slowly eroding the soil as it finally drains.

Do you need rebar for 4 inch slab?

No, you do not need rebar for a 4-inch slab of concrete on grade. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required. Rebar is recommended on concrete measuring 5 – 6 inches thick.

What do you spray on concrete after pouring it?

DO spray new concrete with water. Known as “moist curing,” this allows the moisture in the concrete to evaporate slowly. Moist-cured concrete can be up to 50 percent stronger than concrete that was cured without being dampened!

What is wooden float?

A woodworking float (more rarely used in silversmithing), also called a planemaker’s float, is a tapered, flat, single cut file of two types: edge float and the flat sided float which are traditional woodworking tools generally used when making a wooden plane. … Floats are similar to rasps and files.