Problem Solving Forum
October 11 - October 17, 2010
How do I determine when a cementitious-based mortar used to repair exterior concrete is ready to be coated?
David Grove of Shaw Nuclear Power Services on
November 9, 2010:
The criteria for what you are asking should b ...read more The criteria for what you are asking should be based strictly upon what you are trying to do. If you are going to paint the surface for barrier- type protection, then preforming a plastic sheet test is only part of the answer. I would suggest that you contact the technical service department of the coatings manufacturer for more specifics. Cementitous grout is like regular concrete and most manufacturers require a minimum cure of 28 days, but will concede to a minimum hardness and no moisture. Be careful that the plastic sheet method requires a seal around the edges. Many only use tape and do not consider that the irregular surface will invalidate the results.
remko tas of Futuro SRL on
October 26, 2010:
An inexpensive way to determine if the humidity le ...read more An inexpensive way to determine if the humidity level of the concrete is low enough to be coatedis to tape a medium- sized plastic sheet to the surface in the evening and see if there is any condensation on the inside in the morning. You can also use special humidity gauges for concrete.