I have bought a concrete hacienda-style home in south Texas. Not masonry. Not concrete block. The walls are 12-14 inches of concrete thrown at upright screens. It was built in 1956. My question is: it currently needs EVERYTHING done to it including a new roof. It has a flat roof (actually three roofs of concrete>gravel>asphalt with insulation in between. It leaks like the inveritable sieve and we need to do something. Does anyone know about putting a roof on that is economical but lends itself ultimately to saltillo tiling with some sort of peak. It is 2500 sq ft with rounded walls and very few corners.