Concrete floor slab survey

There are several ways of measuring concrete slab thickness. In the first instance and if possible, you should refer to the construction documents or look for an exposed edge of the concrete slab to directly measure its depth. If no records are kept/ there is no exposed edge or if you want to validate your findings you can choose between destructive and non-destructive testing methods. The first method- destructive core sampling means that the vertical hole will be drilled through the concrete and the thickness of the slab can be measured physically. Although this method is practically almost successful it is associated with high costs for both sampling and fixing damaged floor. In certain circumstances this method is not achievable; that is true for any listed buildings and in places where intrusive assessment is not permitted. The non-destructive methods are tests with the use of either Ground Penetrating Radar (GPR), Ultrasonic Thickness Gauge or an X-ray machine (for radiographic testing). Each of the non-destructive techniques mentioned above has its own advantages and disadvantages but overall can be viewed as complementary to one another. It is worth noting that industrial radiography emits harmful to humas x-rays or gamma rays and therefore is the least safe method.

In short, the answer is no- GPR concrete floor slab survey and concrete condition assessment are 2 different services. GPR concrete floor slab survey is a separate service which can be a part of a concrete condition assessment of reinforced concrete structures as it can detect voids, delamination and (in academic environment) rebar corrosion. Concrete condition assessment except Ground Penetrating Radar (GPR) survey will include other types of tests such as: carbon depth testing, chloride analysis, sulphate content, acoustic sounding, half-cell potential, HAC content, cover-metre, petrographic analysis and cement content.

Concrete slabs are used to make flat surfaces like floors, ceilings, and decking areas. They are laid horizontally to create a flat surface. A slab is generally several inches thick and supported by beams, columns, walls, or placed on the ground.

The thickness of the concrete slab should be determined based on the several factors. Amongst those would be: maximum loads the slab would need to bear (dead load- slab’s own weigh and live loads- weigh of the equipment and/or vehicles using it); intended purpose of the slab (slabs for use of the heavy vehicles will be thicker); type of the subgrade material (typically a bottom of the payment created by compacting native soil); environmental factors (eg. freeze-thaw cycles etc.); presence of reinforcement (type and density of reinforcement will impact on concrete thickness). All those must be considered to ensure structural integrity and adequate durability of the concrete slab.