The Liverpool cathedral is circular in plan, which represents a complete break form the traditional, long, narrow English church. This makes it possible for 2,000 people to be withing 60 feet of the sanctuary. Since no material is known to have lasted 500 years in an environment compatible to that of Liverpool, with its high winds, marine atmosphere , and chemical an other industrial air pollution, it was necessary to design with special provisions for longevity and maintenance. All concrete has a slow a water cement ratio as possible, since this is know to improve durability. Scrupulously clean aggregates with a regular grading of coarse and fine proportions were use. A limestone aggregate was chosen because this material is known to have elastic properties most compatible with that of the cement matrix. External faces of the concrete frame are clad with a white mosaic which rain can wash clean of pollution. Internally, the concrete is untreated.