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.
Moisture in concrete walls.
Concrete masonry walls are less affected by the problems associated with moisture infiltration and condensate than other building materials i e.
Read our tips for concrete moisture testing in the real world to learn more about concrete moisture testing.
In extreme cases moisture intrusion leads to spalling and could even necessitate wall replacement.
It happens when there s excess moisture coming in and it can t get out of your house.
Exterior humid air that enters the basement and condenses on cooler surfaces.
Interior moisture sources such as humidifiers unvented clothes dryers bathrooms and cooking as well as the moisture in concrete after construction.
Typically this will cause moisture related flooring problems or cause mold and mildew growth.
Above grade and below grade water can weaken the structure of a building by causing rotting corrosion and many more moisture induced issues.
When you read in a sealer data sheet that the mver needs to be 3 pounds or 5 pounds what that means is the number of pounds of water vapor per 1000 square feet per 24 hours.
The science behind moisture in walls is easy to understand.
Some flooring system manufacturers have products that can handle 95 rh or mor 2.
For example if the temperature in the room is around 80 degrees fahrenheit and the rh is 50 then a safe level of moisture in the wall would be about 9 1 mc.
Condensation proves a pervasive threat to buildings especially walls and concrete foundations.
Water vapor leaves the surface of a concrete slab at a rate that is called the moisture vapor emission rate mver.
It also saturates insulation reducing energy efficiency.
Liquid water from rain or ground water.
How moisture gets into concrete.
There are just three sources of moisture.
Measuring moisture in walls.
Corrosion rotting mold delamination blistering and volumetric changes.
So how can you be sure if the walls in a structure have a safe level of moisture.
Concrete is like a sponge absorbing moisture from under the concrete which causes the moisture to come up through the concrete capillaries.
Controlling moisture in masonry is essential to preserving the integrity of your building projects.
Rising damp usually occurs in masonry.
If you have damp patches bubbling paint crumbling plaster or powdery deposits on wall surfaces close to the floor rising damp is probably the culprit.