Many design professionals choose not to use welded wire fabric in slabs or pavements because they believe the amount of cover can't be controlled. To address these concerns, research was conducted in 1996 to determine if WWF was at its correct location in a completed slab or pavement in which supports or a two-course concrete placement was specified. The results of the research show that the cover of WWF can be controlled within specification limits if adequate supports are provided. An effective way to determine the amount of cover is to use a portable battery-powered cover meter that induces a magnetic field into the concrete through a hand-held probe.
Cores taken to reveal the strength of a slab on grade sometimes reveal another problem. They may reveal a core that is thinner than the specification. Questions then arise about whether the entire slab is out of spec, and if so, how thin it is.