Architecture / June 2, 2018 / .
The site topography i.e. the natural site features, ground conditions and obstructions, existing and adjoining building, and underground and over-ground services all impact on how the building is designed and subsequently constructed. The nature of each site must be individually checked to establish potential problems. Greenfield developments cost less than brownfield sites which may incur significant demolition, site clearance and remediation costs. Heavily sloped sites require extensive stepping or cut and fill operations and such sites may be dangerous and adversely affect the working conditions and productivity of operatives and plant output. Sites with poor loadbearing capacity will require more expensive foundations while exposed or waterlogged sites will also reduce overall productivity. The cost of dealing with unforeseen ground conditions, archaeological finds and encountering uncharted buried services may be substantial and will be borne by either the client or contractor, depending on the form of contract employed.
Many construction projects involve the design and construction of a building which is tailored to meet the clients specific requirements. No two construction projects are identical - there is no such thing as the average building project. The cost of the building will depend on its particular characteristics and these are largely determined by the architect. The design options are almost limitless and the resulting costs can be difficult to forecast reliably in many cases. On the other hand, certain types of buildings such as schools have well established cost histories and are usually subject to a cost limit.
The choice of the material, and hence the cost, may be influenced by factors other than aesthetic qualities. For example fast-track construction projects may use a steel frame in preference to an in-situ or precast concrete frame in order to reduce overall programme durations. Although the concrete option may be cheaper, the shorter programme achieved by using steel may offset this initial cost advantage. Technical decisions such as these are made for each building element and these have a direct bearing on the eventual cost. Where considerable repetition can be achieved it may prove economical to prefabricate certain structural elements or to standardise various components and fittings.
Once a decision to build has been reached the client will be anxious to have the building completed as quickly as possible. For many clients early completion may be the overriding priority, for example where staging a major sporting event is scheduled, or where a client is attempting to establish a market presence ahead of competitors, or to avail of tax incentives. Time is also of the essence in emergency situations such as fire or flood damage or where stabilisation works are required to dangerous structures.