There are a number of products to use to fix a problem but be sure to choose products that are designed for waterproofing. Each product will have a different application process so it's a good idea to read the label and instructions before waterproofing basement walls. Prepping the surface is the first step which includes: clean the wall and remove any mold and/or mildew. Then cracks can be filled and the walls and floor can be painted with a waterproofing paint.
Cracks can occur in concrete walls due to the structure settling or the land has moved. Cracks can be fixed with epoxies and on the interior of the foundation walls. Your goal is to fill in and seal the cracks to prevent any possible seepage of water. Some products are so advanced that the warranty may be extended from 10 years to lifetime. A warranty is a good thing to remember when waterproofing basement walls.
In addition to using epoxies, you can apply a waterproof membrane on the walls. These membranes are very cost effective and can last a long time if installed per the manufacturer's instructions. This application process for waterproofing basement walls should not be rushed and once the application process has been completed, time should be allowed for drying and curing. The end result will be a very protective waterproof layer and will be very durable as well. You can choose either a liquid or a solid membrane.
A liquid membrane can be applied directly to the foundation walls and floor. Once cured, water will not be able to penetrate the new barrier. A solid membrane is made with little pockets which collect water and drains into a drain that is in the basement floor.
Is your foundation constructed from cement blocks? If so, consider installing what's called an interior drain system. This particular system is actually a very old type of system that has evolved somewhat over the years. This is a system in which a drain tile collects water that the cement blocks collect and carries it away to a sump. The interior drain tiles will also ensure that your basement will stay dry for many years.
Another system is called baseboard drainage. This system is very effective and cost effective. Weep holes are made in the floor and collects any water that may have entered. The water is then carried away via baseboards into a pump and then a basic drain.
Although interior water drainage does remove water from the inside, it's not technically waterproofing. It does work successfully to stop water from harming the foundation and many systems are recognized by the Building Officials and Code Administrators as effective processes. Waterproofing basement walls can and should be done whether by the homeowner or a professional.