How to Tell If Water Is Penetrating the Basement Wall?

If a humidity (hygrometer) is available, obtain humidity or moisture readings in at least four to five different locations within the basement, Take readings, before and after periods of significant rainfall, and preferably for a period of two to three days. Humidity readings or vapor readings that consistently read above 80 to 85 percent are indicative of water infiltration and retention. If no humidity device is available, assess the humidity based on the following scale: If the basement feels and smells damp or moldy all--or most--of the time, this indicates a probable high humidity. If the basement feels and smells as before only after very heavy rains, this points to a moderate humidity. If the basement feels and smells clean almost all the time, this suggests a probable overall low humidity. Proceed next to an examination of the details of the basement walls and associated areas.

Begin at the furthest corner of the basement and carefully inspect the walls for:
1. cracks
2. fissures
3. droplets of moisture
4. efflorescence (salt crystal accumulation at the surface of the interior basement wall
5. obvious water stains on the wall or floor that indicate gross infiltration of water.

Use a flashlight to illuminate poorly lit and dark places on the walls. Make sure to check from the top of the wall to the base of the wall. Check the basement floor where it joins with the wall for cracks and fissures and evidence of water damage.

Use a flashlight to check the boards and joists as they rest upon and near the wall. Look particularly for green, fuzzy, thready mold growths or even real mushrooms growing on the wood surface. The presence of mold or mushrooms is an absolute indicator of an excessive amount of moisture in the basement wall area. Write down with a pencil a paper those areas, by a crude diagram, where mold has been seen or suspected.

Recheck the notes taken and repeat the entire process above one more time. Make a checklist of any new or previous findings.

The procedures that were used here provide the initial assessment needed to make the initial determination of water penetration into the basement. The next steps will require remediation procedures to interdict water infiltration and dehumidify the basement.