At what stage should we employ a Quantity Surveyor?
Ideally a quantity surveyor should be consulted at an early stage. Even with a simple outline drawing a costing can be carried out. The assumptions used can then drive the design process. There is no point having a wonderfully design building using expensive materials if it's too expensive to actually build. We can help by being part of this process and giving the parameters for the designers. Whether you choose a quantity surveyor or not, the point is to nail down the costs early on.