Foundation Stabilization and Repair/water seepage
I am currently installing laminate flooring in my house (downstairs) via Home Depot installers.
Prior to laying down the laminate floor, they checked the moisture content of my cement slab foundation. My foundation is all one large cement slab.
And they found parts of the foundation to have a higher moisture content than other parts. 6% vs. 3%.
Now, when I moved into my house several years back, I discovered that the HOA (which control the sprinkler system) had been watering our lawn for 365 days a year for 3 years. Consequently, the ground was always wet on one side of our house. After a great deal of trouble, I got the HOA to stop watering every day so now we are watering on a regular healthy basis.
I told the HOA that I was worried about foundation damage as well a damage to the fence where the ground was always wet. I dug a trench to transport the water to a drain, and that seems to have fixed the problem of the ground being so wet all the time.
Now the side of the house which gives the high moisture content is the same side where the ground was always wet. It has been about 4 years from the time the HOA started watering regularly to now when the laminate is being installed. So the extra water has had 4 years to evaporate/dissipate/etc
My question to you is, how likely is it that the overwatering for 3 years has not evaporated in the past 3.5 years? And is that the source of the extra moisture which is present now?
Depending on the climate the last several years one would expect that the moisture
would have dried out. However,if there is a surface drainage issue such as a negative slope and or gutter downspouts or lack of gutters the dry out may not occur totally.
W/o knowing what subgrade preparation was used such as vapor,or capillary methods it is challenging to say to what level the slab will dry out.
If you are in a rather dry climate in your area there is always a possibility of under-slab seepage from water or sewer lines. These can be tested if the moisture level remains.
I don't know the age of the structure but it used to be common in many parts of the country to place ductwork beneath the slab. This has a drying effect in the areas over the ductwork.
Moisture beneath slabs can have numerous sources. Sometimes there are no easy answers.