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Waterproofing membranes come in two flavors. You've got your sheet membranes, and you've got your liquid membranes. Naturally, which one you use depends on what you want to do.
Sheeting membranes will give you highly trafficable surfaces (you can walk on it) and provide some insulation. You can apply sheeting membranes to your basic substrate with an adhesive. You'll need to make sure your sheets overlap by about 4". You will also have to bond them to each other with an adhesive or heat welding. Be aware that the seams are the weakest point in the system.
In general, sheeting membranes don't resist exposure very well, offer little temperature stability, and don't recover well from deformation (like most of us.) What's more, if the substrate is water logged, you'll need to vent sheet membranes or you'll have a severe bubbling problems on your hands, which stresses out your adhesive, which could cause your adhesion to fracture.