How Damp Should a Wall Be

* A moisture content of less than 5% is perfectly acceptable. * For a wall to have rising damp and it must have a moisture content in excess of 5%. * A moisture content of less than 5% is unlikely to be rising damp. * A wall must have in excess of 5% hygroscopic moisture content before it has rising damp.

How much moisture is too much in drywall?

If the moisture content (%MC) of drywall exceeds even 1%, then the drywall can be considered “moisture-compromised” and in need of either drying or removal depending on whether mold has begun to grow.

What is acceptable moisture level in concrete walls?

1. What are the acceptable moisture levels in concrete? Acceptable moisture levels in concrete according to ASTM standard, when testing via ASTM F2170, the RH level of a concrete slab needs to be at or below 75% — unless the flooring system manufacturer provides alternate guidelines.