When you touch the concrete walls of an unfinished basement, they may feel cold and clammy. Although most people think of concrete as very solid, it is actually porous, and never fully "dries." Instead it "cures," sealing the water molecules into the substrate of the wall. Water can get in through cracks, but even with no cracks, the concrete wall will never be waterproof.

Concrete becomes damp in two ways. Although it feels dry to the touch, cured concrete actually contains water that is bound into the substrate of the material. In addition, the surface is porous, and will absorb more water when it is exposed to rain or a humid climate. If you do not install basement waterproofing systems, the long-term exposure can result in concrete that is thoroughly damp all the time, and a bed for mold and mildew.

Although there are varieties of concrete that are resistant to water penetration, it is either unsuitable for many contemporary housing designs, as in the case of ferroconcrete, or extremely expensive, as in the case of hydrophobic concrete. But neither of these is actually waterproof the way basement waterproofing systems are. The ferroconcrete uses a fine aggregate and dense mix to limit porosity and the hydrophobic concrete mixes in compounds that make surface moisture bead and shed to a greater degree than normal concrete.

If you want the concrete foundation to be really water-resistant, the best thing you can do is to use basement waterproofing systems. Preferably a bitumen barricade for waterproofing basement walls, similar to those used beneath shingle roofs should be applied outside the foundation prior to back-filling around it. This will ensure that the foundation is constructed upon a layer of stone which will support drainage.

It would be best to waterproof your basement as part of the initial construction, but if you have to do it after construction is complete, there are basement waterproofing products that will work. You can apply these products to the interior surface of the foundation, though they will probably have to be reapplied periodically. A water management system can shunt water away from the foundation, reducing exposure. Plastic sheeting is a common choice, but mold and mildew can accumulate under the damp sheeting, causing more problems than it solves.

The price of waterproofing depends on the cost of applying it and the level of protection it provides. In the worst case, an improperly waterproofed foundation will flood because of water leaking through the concrete. In such a situation, you can use a sump pump to remove the standing water that accumulates. However, this will will only keep the water from rising, rather than stopping the flooding altogether. Best to figure out what's wrong and address the main problem rather than treat the symptoms as they arise.

The dampness you sense when you place your palm on the surface of an unfinished concrete cellar wall is because of the moisture it contains. Without basement waterproofing systems, continuous exposure can work water all the way through the concrete and supply your basement with a steady stream of moisture for mildew to grow on. If, however, the foundation must be waterproofed after the construction, you can find basement waterproofing products in the market which can be placed on the interior face of the foundation. The cost of waterproofing basement project will vary depending on the type of system and whether the installation is a do-it-yourself project.