Interdependence of the functional element costs of buildings

This work is an investigation of interdependence between the basic units of conventional cost planning employed by quantity surveyors in the UK, functional elements. It is concerned with interdependence only in so far as it affects the estimating and planning, on behalf of the client, of the initial capital costs of construction. Conventional cost planning theory and practice are discussed, and the general assumptions implicit in these conventions, regarding the interdependence of elements, are identified. Samples of element costs for a number of building types are analysed statistically to test the validity of the assumptions of conventional cost planning. and to determine the general nature and extent of interdependence in the elemental data used for cost planning. The results do not support the conventional approach, showing the interdependence of elements to be generally insignificant in the context of the high levels of variability found in cost planning data. Two models which depict the interaction of design decisions in the generation of building cost are studied, resulting in the identification of fundamental shortcomings in elemental categories as a unit of sub-division for the purposes of cost planning in the early stages of design. The implications of these shortcomings are pursued leading to discussion of the relationships between elemental categorisation and the design and production processes, and the suggestion that a method of categorisation that is more closely related to production processes would have advantage over functional elements.