Little did you, the common customer know, but there actually are legal definitions for basement waterproofing. Waterproofing is defined according to the law as "any measure which prevents water from reaching a particular area." That's all well and good, except that there's also this other legal definition called damp-proofing, which is defined as "any measure that slows water's access to a particular area." The problem, of course, comes when you hire a company to waterproof your home and than unwittingly sign a contract that says they're going to 'damp-proof' it. Basement waterproofing is nothing to mess around with -- just a little bit of water in there and you'll be calling the mold removal people to come in and de-mildew the entire place. But these folks will happily take thousands of your dollars to damp-proof your home, knowing full well that in order to protect your belongings, they'll have to come in and do it again within a few years. Most state's building codes require a basement to be damp-proofed when it's built, so that's all most contractors do. They'll dig a trench all the way around the outside of your basement, slab a layer of mortar on the wall, and then lather it with a tar- or asphalt-based "sealant". That's damp-proofing. Within months, the tar is wearing off. Within a year, it's almost gone and the mortar is starting to erode. Within a few years, there are huge cracks in the mortar and water is leaking into the bricks or blocks of your basement walls. If you want real basement waterproofing, you can't use something that's mixed and pourded on and slathered with a trowel. You need a waterproof membrane that gets wrapped like cellophane around your basement walls. These membranes are what commercial buildings use to waterproof their basements, and they work for decades without a repair. For the homeowner who truly never wants to worry about basement repair (or mold removal) ever again, you don't have to stop there, either. There are new mortars out there that mix what amounts to superglue in with the mortar: the superglue helps the mortar hold onto the wall it's being slathered on and stops up the pores in the mortar that make it vulnerable to water in the first place. After the superglue-mortar and the plastic sheeting, you can even take it a step farther and add a layer of flasing-grade elasto-meric acrylic latex resin to your outer wall. Basically the height of waterproofing, the resin was developed as a way to prevent rainwater from leaking through a flat roof, so you know it'll work well on your walls. Finally, there's the ultimate water-proofing effort: an air gap. Air gaps around the outside of your waterproofing layer --- generally provided by something not unlike a hardened kind of bubble wrap -- prevent the water from even collecting against the waterproofing to begin with. The water leaks into the air gap, flows down to ground level, and drains away before it can build up and threaten the basement waterproofing in the first place. These measures are commercial-grade, which means they're expensive, but if you intend your basement (and the rest of your house) to live forever, they're the last basement waterproofing measure you'll ever need.