ZeLro stands for 'Zero Leak Roofs' and is an initiative that ensures 'best practice' in the design and construction of profiled metal-roofs, so (as the name implies) they don't leak. This book is a quality system for achieving 'Zero Leak Roofs' using profiled metal. It focuses on client expectations, implementation and weaknesses in current design and construction. This guidance is not only applicable to constructing a watertight roof; but to building a cost-effective roof, free form defects - that will avoid later maintenance costs. Other features include - selection procedures for appointing a roof installer, supplier roles and responsibilities and safety.