Check out Resource Conservation Technology. They sell an acrylic roofing product I used when I built my wife's photo lab in Chelsea. (43 W 24th St, third floor, Chelsea Photographic. You could drop by and check it out if you were in the neighborhood.) The wet chemical environment required I waterproof 2200 sq ft of darkrooms, halls, etc, with 4" curbs everywhere to insure any spills would be contained. Using a pair of scissors and paint rollers, I completed this task in two weeks by myself. It has been in constant use for approaching 12 years, walked on, worked on, without issue. I have seen the same covering used locally on old metal roofs, sprayed on without the fabric bedding. Non-toxic, inexpensive, durable. They also sell EPDM membranes and other Scandinavian building products.

If you use wooden siding on your house, it must be back-primed or you will never keep paint on it.

Local codes where I live preclude building on piers, and they are more prone to shifting that full foundations. Alaskan slabs are infrequently used for outbuildings.