If you're a concrete contractor, it's important that you maintain adequate clear cover in vertical concrete structures. With proper cover, reinforced-concrete structures are likely to exhibit improved structural integrity and finished appearance as well as greater resistance to fire and corrosion. Without it, the reinforcement is vulnerable to corrosion and the concrete to early deterioration. Though designers specify clear cover for vertical formed surfaces, they seldom specify the means for maintaining it. That's the contractor's responsibility.
Fortunately, there's an easy way to help maintain specified cover when you're building cast-in-place vertical members like walls or columns: Use side form spacers. Some of the most popular side form spacers on the market today are bolsters, wheels and chairs. These all-plastic or steel-wire devices are easily installed before concrete placement by either wiring or snapping them onto the steel reinforcement at regular intervals. The side form spacers can then maintain the proper distance between the reinforcing steel and the form face after concrete placement. Clear cover provided typically ranges from 1/2 inch to 4 inches.