Concrete Placement and Finishing

Placing Concrete

• Delivery of Concrete: Ready mix concrete should be delivered and discharged as quickly as possible. 1 to 1 ½ hours is usually reasonable.

Some water is often withheld from the batching process and can be added at the jobsite. Addition of unnecessary water is discouraged as it dilutes the strength of the designed mix.

• Placement: Concrete should be placed as closely to its final position as possible. Dragging or raking it from one corner to the middle of slab compromises the concrete.

• Leveling: Screed twice to level the surface and immediately bullfloat at a right angle to the direction of the screed to remove high and low spots.

• Finishing Procedures: After bullfloating, bleed water must evaporate before final floating and finishing procedures begin. Grooved control joints can be cut into the surface once the concrete is firm enough.
• Final Finish: A light broom finish is recommended, particularly on exterior concrete such as driveways, walks, and patios and should be broomed perpendicular to vehicular traffic. Where a smooth finish is desired (garage floors) a hand float finish should be used. Machine floating and/or troweling is not recommended for residential concrete.

• Curing: One of the most important aspects of proper concrete placement is the timely use of curing products and procedures. Effective curing is absolutely essential for surface durability. Curing compounds and other methods allow the concrete to maintain a favorable water content for proper hydration (or curing) of the concrete surface Curing compounds should be applied as soon as possible after final finishing operations are complete.

During hot and dry conditions, ponding of the slab is recommended. A continuous water supply is kept on top of the slab for 72-120 hours. In cold conditions insulating blankets should be placed on the concrete as soon as possible without marring the surface and left on until temperatures rise above dangerous levels.
• Sealers: If the concrete was not cured with a cure-and-seal product. A sealer should be applied after the design mix set time is reached (generally 28 days)

• Initial Cure Time: Vehicle traffic for a driveway should be disallowed for 7 days following concrete placement.


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