How to Do Reinforced Slab Flooring

Well poured and finished concrete will not crack.

You can install a slab floor yourself but you will have to make sure key parts of the work is done properly. You have to pay close attention to the sub-slab material, the installation of a vapor barrier, the placing of the reinforcing steel and the compacting and curing of the concrete. Before starting, you have to decide on the concrete strength required and the thickness of the slab. Any mistakes along the way may result in a weakened and cracked concrete floor.

Things You'll Need

• Concrete form, if required
• Gravel
• Sand
• Vapor barrier
• Reinforcing steel wire mesh
• Concrete
• Finishing machine

Instructions

1. Check the building design and local building codes to determine the strength and thickness of concrete required. A 4-inch thick concrete floor with 2500 psi may be enough for residential foot traffic but, if the floor will be supporting walls or posts, it will have to be twice as thick in those locations. Building codes may also require additional thickness or strength depending on local factors.

2. Build the concrete form around the edge of the slab if the slab is not going to be poured inside a foundation. Place four inches of gravel where the slab will be poured and compact the gravel. Pour enough sand over the gravel to create a smooth surface and compact again. Place a vapor barrier over the sand to keep the room above the slab dry. Place the steel wire mesh on the vapor barrier and support it so that it will be located within the top third of the slab.

3. Pour the concrete, starting at one end and pour successive batches so that the quantities touch and mix. When the concrete has been poured, pull a long board across the concrete to level the surface and fill in low spots. Let the concrete sit until bleed water has evaporated from the surface. Use the finishing machine to give the concrete a smooth surface finish. Let the concrete cure for at least three days.

References

• American Concrete Institute: Guide for Concrete Floor and Slab Construction
• Portland Cement Association: Cement and Concrete Basics
• Concrete Answers: Residential Floor Slabs