||Waterproofing comes in a couple of different methodologies. First there are barrier coatings that for a tough durable film over the surface to prevent moisture from blasting through to the substrate. These are products such as you see like Watertite and Drylok.
Another form of waterproofing is to use penetrating hydrophobic materials including silicone and siloxane to repel water from surfaces that you do not want to look painted. Concrete pads and flagstones, natural stone and pavers all last longer if you can keep the water from staying in the surface.