Cover survey

Concrete slabs are poured to tight tolerances for both structural and economic reasons. Using less concrete keeps the project costs down and results in a lighter and thinner structure. Insufficient cover thickness, however, can lead to reduced slab strength and increased risk from fire and corrosion.

When assessing concrete condition of a building or a structure performing cover meter survey might be necessary. Concrete cover meter survey will determine the depths from the surface of the rebars or other metallic components as well as thickness of concrete cover above rebar layer.

Concrete cover meter survey is done by accessing the concrete slab or surfaces and performing a series of scans with the cover meter or GPR. The data collected can then be reviewed to extract the locations and depths of reinforcement within the slab and, when possible, diameters of the bars.

Survey data is saved and used to produce a drawing(s) and a report.

Concrete cover survey can be performed using either GPR or a Cover Meter. Both devices have their pros and cons.

A cover meter uses electromagnetic pulse induction technology- this only works on metallic objects and will usually be blocked by the first metallic layer encountered (for example the first rebar layer).

A GPR uses RADAR technology to detect both metallic and non-metallic objects. GPR (Ground Penetrating Radar) is usually able to penetrate beyond the first rebar layer and detect other features within the slab, such as other reinforcement layers and the slab thickness.

Both devices are reliable if used by an experienced surveyor, however KB Surveys will typically choose to use a GPR because of its additional capabilities.