Pettit Singleton Associates (PSA) are one of the North West's largest Building Services Engineering Practices, with offices located on Preston Docklands and at Warwick Bridge, Carlisle. The philosophy of the company is to strive to provide the highest standard of service to our clients, with the aim of exceeding their expectations whilst offering innovative, practical and value for money building services solutions. This pursuit has led to PSA being awarded many prestigious and technically demanding projects. The key to our success and growth over the years has been our total commitment to quality and service that is reflected in the projects we deliver. Ultimately our success can only be measured by client satisfaction, which is why we are proud that over 80% of our work is repeat business from existing clients.