Introduction The amount of development that can be incorporated into a given site will depend on a number of potentially conflicting factors. The developer will calculate the floor area required for various uses from a prediction of the market demand on completion. In a volatile property market this is likely to be reviewed at a number of stages during the development process. On the other side of the equation there will be a whole series of constraints that may limit the possible floor area that the site can accommodate. If this falls below the developer’s economic limit, then it may be necessary to vary the size of phases, delay development entirely until the market picks up, or sell the site (preferably with planning permission).