existing building consists some duct work, it should be tested for obstructions, deterioration and air leakage. Air conditioning: Air conditioning ducting and equipment can be expensive and demand a lot of ceiling space. These economical implications must be considered for the new use of the building before deciding the installation of an air conditioning system. Plumbing: Old buildings used galvanized iron pipes for plumbing which may be subject to serious deterioration over the years. Proper connection to municipal sewers must be evaluated and fixed if broken. Electrical: While the electrical wiring may still be intact, the panel boards, junction boxes and electrical feeders may not be as per the present day fire codes. Additionally, the switch boards may be outdated and have to be replaced. The architect and engineers must also determine of additional transformer vaults and feeder lines are necessary. Roof and waterproofing Older building roofing systems generally comprise the roof, parapets and cornices. Projecting metal cornices are subject to corrosion. Parapets may be subject to cracks and degrading mortar joints. A careful examination of the top-floor ceiling may reveal water leakage. Stairways and exits The stairway requirement for a building should be derived from present-day building codes for fire and safety. Strategic placement of new staircases and layout for maximum access should be done in order to maximize space utility and minimize the burden on the structural system. Designing to save energy Redesigning the existing building for new use must accommodate energy conservation strategies. Some of the most important methods of energy conservation are, reducing heating and cooling loads through building envelopes, maximizing natural ventilation potential, using daylighting and energy efficient lighting fixtures and so on. Building envelope A building's envelope protects it from the external weather conditions. To prevent the extreme climate of the exterior from causing discomfort to occupants, buildings use mechanical heating and cooling systems. If the building envelope is not designed well, the heating and cooling loads on the mechanical equipment might go high. Therefore, for maximum energy efficiency, building envelopes should be the first layer to block out external weather conditions, then the load on the equipment can be minimized. The U value of walls should not be more than 0.06 when winter design temperatures are less than . This can be achieved by using a combination of exterior wall materials to form a high resistance wall assembly. Windows and doors The fenestration