Foundation specialists assess ground conditions and provide structural support for buildings and other structures. Their work may involve preparing sites, excavating and constructing new foundations, or strengthening existing ones where movement, settlement or changes to the building have affected their stability. Depending on the site and the structure, they may work with concrete strip or raft foundations, piles, ground beams and other foundation systems. Services can include site investigations, foundation design in coordination with engineers, underpinning, piling, repairs and monitoring of structural movement. Specialists may also advise on access, drainage, soil conditions and nearby structures before work begins. Projects range from extensions and new buildings to remedial work on existing properties. The method used depends on factors such as the building's weight, the depth and type of soil, groundwater levels and the cause of any structural movement.