While “House Extensions” often refers to building projects that alter the structure of an existing home, it can also include improvements to lawns, gardens, and outdoor structures, such as gazebos and garages. It also encompasses maintenance, repair and general servicing tasks. An extensions is a new room or building which is added to an existing building or group of buildings. An extensions is an extra period of time for which something lasts or is valid, usually as a result of official permission.