WET BASEMENT: FOUNDATION LEAK OR CONDENSATION?
So it is late winter, one week is warm, above zero temperatures, the next week is freezing, and you find water on your basement floor, coming from the concrete foundation wall, but no crack to be seen. Condensation may be the culprit. Condensation is a common problem during fluctuating temperatures this time of year.
Condensation occurs when moist, warm air hits a cold, dry surface. Check to see where the level of soil or grade is on your basement wall. If the foundation wall is wet above the soil/grade line, your problem is almost certainly condensation.
There is no one easy fix for condensation. Make sure there are no gaps in your insulation (Do not, however, add insulation while the wall is still wet as this may cause a mould issue.). Check to see if vents are fully sealed. You may wish to open the windows and run fans to circulate the air. Your hot water pipes are probably wrapped with foam sleeves already, but try wrapping the cold water pipes too. The best thing you can do is decrease the humidity in the basement. A dehumidifier may go a long way in resolving this issue.
While foundation condensation can be troublesome, and even dangerous to one’s health if it is left long enough to cause mould, the silver lining is that it is not an expensive repair requiring a contractor’s services.