Building materials not of metal, in particular for floor structures of riding areas, riding halls, horse racecourses, golf courses, sports grounds, play areas, and lawns, namely, plastic flooring, rubber flooring, and plastic conduits all for drainage and irrigation; floor structures and floor layers for horse-riding, horse racecourses, golf courses, sports grounds, play areas, and lawns, namely, plastic flooring, rubber flooring, and plastic conduits all for drainage and irrigation