The first step in drying out a wet, leaky basement is to find the source of the moisture. This simple test, using plastic wrap and masking tape, will help determine whether wetness is coming from inside or outside the foundation.
Tape the plastic wrap tightly to a discolored area of the foundation. If the moisture is outside the plastic, there is moisture coming from inside the basement.
Probably the easiest way to get rid of moisture in a basement is a dehumidifier.
If the wetness is on the inside of the plastic, you may have a case of the "killer Gs": gutter and grading problems.
Routinely check the condition of the gutters. Keep them clear of debris and add gutter extensions to the downspouts.
For grading, make sure water is properly diverted away from the foundation of the house.
To add an extension to a gutter, first stretch the extension to a length of 4'-5' (enough to draw the water away from the house). The corrugated-plastic pipe, though sturdy and rigid, does pull apart with a little effort (Image 1).
Shape the extension pipe into a 90-degree angle; then slide it over the bottom end of the downspout (Image 2). Secure the extension in place by inserting sheet-metal screws into the downspout (Image 3).
Remember always to aim the extension away from the foundation.
To repair a hairline crack (Image 1), use a hammer and a chisel to open up the area (Image 2). Start at the top and work toward the bottom, chipping a 1/2"-3/4" groove (don't go any deeper than 3/4" or there is a risk of completely cracking the cinderblock).
Use a chisel to remove any loose concrete or debris that may clog up the crack. A stiff-bristled brush will help dislodge any smaller pieces still in the groove.
Wet down the crack's surface with a spray bottle. Wearing safety gloves and working quickly, dump a small portion of hydraulic cement into a bucket, add the water and begin mixing by hand. The texture should be similar to cake batter, so add water and hydraulic cement as needed. Once the right consistency is achieved, grab a handful and work it around in your hand, shaping it into a ball.
Begin to push the hydraulic cement into the open crack.
Quickly use a trowel to slice away the excess cement before it cures. Any remaining flakes of cement can be removed with the brush.
Costs for repairing a wet, leaky basement begin around $15 or $20. This will cover the cost of gutter extensions, splash guards and leaf covers. All are fairly easy to install and should take no more than a few hours to do so.
Medium repair work, such as fixing a hairline crack (Image 1), will cost around $50 and take about half a day to complete.
Serious structural damage to the foundation (Image 2), which can run more than a thousand dollars, should always be done by a professional. If structural damage is found, get several estimates before beginning any work.
Take preventive measures such as applying cement paint; a stiff brush will be needed to apply the paint to cinderblocks. Dip the brush in the paint and apply generously to the cinderblocks.
A stronger preventive measure, cement coating, will actually create a chemical reaction that will bond with the wall. Mix up the cement coating with water until smooth and apply with a very strong brush directly onto cinderblocks.
A condensate pump can be installed to the dehumidifier's hose connection so that instead of going into the bucket, the water will drain into the condensate pump. Hook up a hose to the condensate pump's drain line to pump the unwanted water up out of the basement.