Basement water buildup can come from a number of sources. Before spending a lot of money on so-called waterproofing products, ascertain from where the water or dampness is originating. It does absolutely no good to apply specially formulated coatings in an attempt at waterproofing finished basement walls and floors if the source of the water is coming from poor outside drainage, for instance. It may be cheaper to install a french drain.
Determine if wetness is coming from the outside or from the inside, by affixing a one-foot square piece of aluminum foil as tightly as possible to a basement wall. Leave the foil attached to the wall for a day or so. If the side against the wall is wet when you come back to look at it, moisture is getting into the basement from the outside and seeping in.
If the inside of the foil square is wet, water is originating from the interior of the basement and will appear as condensation on the foil. That will tell you whether to begin waterproofing your finished basement interior or to address the problem outside of the basement.
A typical source of water one should consider before waterproofing finished basement interiors lies in seepage from rainwater. If the home’s property grade provides inadequate drainage when it rains, the water will find its way into a basement. If the seepage is not too heavy, you may be able to alleviate the problem by putting up guttering with downspouts that direct the flow of water out and away from the house. It may be necessary to add extensions to the downspouts or to splash blocks, if those are being used.
If guttering helps, but the grade of the lawn around the basement area slopes insufficiently away from the basement (or even slopes toward it), you may need to do some excavation work as part of waterproofing finished basement areas.
You will need to dig the dirt out at a grade sloping about one inch per foot away from the basement area to a minimum of 10 feet. You can do this yourself or hire a contractor, depending on your budget and the size of the job. Sod or seed the excavated ground as soon as possible after excavation to prevent the bare soil from washing away during heavy rains.
If you are lucky, add ing waterproofing to finished basement floors and walls will only take something as easy as wrapping pipes to insulate them against sweating and/or repairing any leaky plumbing; taking care of atmospheric moisture, in other words. Proper ventilation can also help in this instance: Air condition in hot weather and heat in the cold of winter to not only keep temperatures comfortable, but also to stave off humidity.
Before Purchasing Special Coatings
Coating products marketed for waterproofing finished basement interiors work only in instances of mild and occasional moisture problems, so be sure to read the products warranties/guarantees before shelling out your hard-earned money. In some cases, the problem can be eliminated fairly easily and these type products need not ever be necessary.
The smartest thing to do is to check out the basement for accumulating moisture before you buy the house. If it is too late for that, and you have tried all of the above possible solutions, it is time to call in an expert. It may cost you more initially, but in the long run, waterproofing finished basement areas will then become a thing of the past, and you can then get on with the business of enjoying that now-dry area you have always wanted.