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. The purpose of darbying or bull floating concrete is to level ridges and fill voids left by the screeding operation. It should also slightly embed the coarse aggregate to make subsequent finishing operations easier. Purpose: To level ridges, fill voids, and smooth the surface in preparation for troweling.
Floats also can be used to work in dry-shake color hardener. Unlike finishing with a steel trowel, floating won't close the surface, which is important at this stage to let bleed water out.
A float also helps bring paste to the surface by pushing down the coarse aggregate. What's available: The most common floats for decorative concrete work are made of magnesium, aluminum, or wood. Less common float materials include stainless steel, rubber, and laminated wood or canvas resin. Bull floats have a long handle that you push or pull across large areas of concrete. They also act as screed walls for cutting and filling. Available with traditional rounded corners or with unique square edges.
Weights securely bolted on easily. Easily attach versatile groover accessories to make rough cuts. Straightening rods and outriggers can be attached. Speed floats: A faster and easier float to use, as it is narrower and creates less fiction than a bull float.
T-Slot allows for attaching virtually any bracket, with no hole threads to strip. At 5 inches wide, it is ideal for exposed aggregate. Great choice for following vibratory screed to knock down lap lines. Available with rounded or square ends. Ergonomic, extendable handles no keys required. Magnetic support bar. Individual antivibration system. No visible cables in the handles. Flexible vibration shaft. Lightweight 21 pounds. Honda gasoline engine.
This ensure blades will not bend, twist or warp. The perfect matching of the power unit and boards allow these screeds to work with most slumps. Additional features include: A handle-mounted throttle for fingertip control of vibration.
Operator comfort from an adjustable handle. Operators can work standing up. Cast aluminum frame for longer life and a lighter operating weight. Easy removal of the power head from the boards to switch board lengths. Screed boards are available in lengths from 4 feet to 16 feet. Two-foot extensions can also be added to each end of the boards to extend or make custom lengths. Extension straps are also available to connect two power units and boards together to cover larger pours with the same efficiency.
PRO Grip mag floats are available in three blade styles. The handles, designed in conjunction with a panel of professional finishers, are also ergonomically shaped. Kraft also offers many mag and wood redwood and teak floats. Magnesium hand floats: Cast from the finest magnesium. Designed with just the right broken-in shape. Cast construction allows more knuckle clearance. Placement of handle gives the float perfect balance. What is an Isolation Joint? An isolation joint is a separation of an existing concrete slab from a new concrete slab or wall.
What is the Base of a Concrete Slab? The base in concrete construction is the layer between the sub-grade existing soil and the concrete slab. The base usually a crushed stone material acts as a support between the dirt and slab, and ultimately, reduces cracking of the slab. We are dealing with a garage floor. Bull floating gives a relatively smooth surface and does force aggregate down and brings some sand up to the surface filling small holes and generally leveling.
Can be done from the side of the slab. Bull floating is done after screeding and before finishing, but it can be the final step in finishing Magnesium floats do the same and can add some texture on the surface.
A good looking surface as far as I am concerned. Hands and knees type of work. Steel trowels leave a sommth harde surface and in my experience are used after the previous two finishing methods. In proper hands the leave beautiful arcing patterns ao no trace of their presence whatsoever. Don't forget about control and expansion joints either. The contro joints can be tooled in, or some areas allow for the use of plastic joints which are placed after initial floating, then floated or troweled over and a strip is then remove prior to the concrete setting up.
Consider beams thru the center, but never joints thru a slab. The bull float is used only after the area is screeded. This is step 2.
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