Concrete

Laying a floor covering on a slab that is still releasing moisture leads to adhesive failure, blistering, cupping and mould. Concrete testing answers one question: is this slab ready for the floor going on it? It has to answer it in a way the flooring manufacturer will accept.

This collection covers both survey meters and RH test systems. It includes the Tramex CME5 and CMEX5, the Concrete Determinator kits (CDK, CDTK and CDIK), concrete coatings kits (CCTK and CCIK) and in-situ dataloggers. From Wagner there is the C555 and the Rapid RH L6 system (WFP400, CFP405 and Smart Sensor 25 pack). It also includes Protimeter HygroMaster 2 kits and Delmhorst HT-4000 and TotalCheck instruments.

Choosing a concrete test method

Survey meters find the wet areas. Non-destructive meters such as the CME5, CMEX5 and C555 read near-surface moisture quickly across a slab. Use them to decide where to place RH tests, not as the final answer.

In-situ RH tests give the decision number. Probes or sensors sealed into drilled holes measure relative humidity within the slab, as described in ASTM F2170. This is the result most flooring and adhesive manufacturers specify. Always check the limit on the product data sheet.

Hood tests for surface conditions. Humidity hoods and sleeves with a thermo-hygrometer measure the air immediately above the slab.

Speed versus volume. Single-use sensors such as the Wagner Smart Sensors suit installers testing many sites. Reusable probes with a meter suit inspectors who test often.

Read five steps to moisture testing concrete and an introduction to the Tramex CMEX5. Installers should also see flooring.

Practical advice

'Is my slab dry?' needs another question: dry enough for what? A handheld concrete meter is good for comparing areas and finding likely trouble spots, but it doesn't replace a specified in-situ RH test when a flooring system requires one. Check the floor-covering manufacturer's limits and test method before signing off; a low surface reading isn't a blanket clearance.