The easiest way to waterproof a basement is to waterproof the inside walls with a sealant. There are various options for the types and prices of sealants, ranging from concrete sealers to waterproofing paints. Other options include plastic sheathing in combination with an interior drainage system.
To make sure that moisture in the walls of a basement is coming from the outside and not the inside of the space, a simple test should first be performed. By taping a 1-foot piece of tin foil on one of the inner walls, the direction from which most of the moisture hits the wall should be discernible. If there is condensation on the outside of the foil, there is high humidity inside the basement, which can be corrected with portable dehumidifiers or a central dehumidifier system for a larger space. If moisture is coming from outside, the walls can be effectively sealed.
Waterproofing paint rolls on four times as thickly as regular paint, and it is the quickest and most cost-efficient way to seal the inner walls. It can be applied over painted walls, and once it is cured, it can be painted over. Other application options, such as silicate-based sealers or concrete waterproofing coats, tend to be more labor intensive because the former cannot be applied on painted surfaces and the latter needs two coats of application.