The hydrostatic pressure on the foundation walls can break down the integrity of the concrete over time. Waterproofing the outside foundation walls is one of the best but most expensive ways to keep water from coming inside your basement. The cost to this project comes from having to dig out the area around your home to get to the walls (see Figure 3.6). Of course, you want to make sure you also install a foundation drain while you’re at it. Because it is expensive, waterproofing is a fix only those with water infiltrating their basements or homes should consider.
Figure 3.6 Excavate the soil from around your home to expose the foundation walls.
Make sure you get a product that actually "waterproofs" and not just "damp-proofs." Waterproofing is obviously better because damp-proofing products won’t bridge the gap of cracks. Waterproofing products are sprayed or applied in sheets and their elasticity will bridge the gap in cracks and holes. After applying a waterproof membrane, install drainage panels attached to the outside of the foundation; this helps the water travel to the foundation drain through channels on the panels. These drainage panels have become quite popular and are now installed on the foundation walls of most new construction.
A combination of waterproofing the outside walls and foundation drains is the best way to prevent rainwater from coming into your basement.