Plastic Sheet Moisture Level Test
January 27, 2019
New concrete can contain high levels of moisture and if coated before it is sufficiently dried out, will surely lead to paint problems. There are several kinds of moisture tests for concrete but here we will examine a quick and easy method that is widely used but not infallible.
The Plastic Sheet Method (ASTM D 4263) can help determine if there is moisture movement at the surface in concrete floors and walls. However, it cannot determine the quantity of moisture or detect if there is moisture at deeper levels or that could move up due to a missing moisture barrier. It may indicate more testing is required. It is recommended to use more than one type of test especially for flooring applications
Clean the surface and tape an 18” square of plastic firmly over the concrete with a strong waterproof tape. Leave for 16-24 hours before checking for moisture on the inside of the concrete sheeting. If there is visible evidence or a dark patch on the concrete – the surface is too wet to proceed to painting.
For Best Results
- Test in multiple spots. Place patches every 500 sq. ft and on walls, every 10ft of vertical rise starting at 1ft above ground.
- Don’t avoid problem areas. If there are cracks or other defects place a patch over them for most revealing results.
If concrete is not fully dry but the job is time sensitive, request technical assistance from your nearest Harris or B-H Colourcentre
Check out our other great articles in this February edition of Paint Pro!