Your Residential and Commercial Concrete Block Manufacturer. Operating out of Simpsonville, South Carolina, Southeastern Concrete Products Upstate is your source for the best in concrete products. We specialize in concrete building block and retaining wall block. We also sell concrete pavers, masonry cement, parking bumpers and splash block. Southeastern Concrete Products Upstate has everything you need all in one place,... Read More about Southeastern Concrete Products Upstate