Architecture / June 25, 2018 / .
The factors influencing this decision include: Is the more expensive option a worthwhile investment? If it can be demonstrated that savings will arise as a consequence of incorporating the more expensive alternative, then the client is well advised to choose this option. The quicker the payback period, the more likely it is that the more expensive option will be chosen. How flexible is the client‟s budget to finance more robust, better quality or more economic structures or systems? Regardless of whether the client wants the more expensive alternative he or she may not be able to afford it. Retrofitting, however, is inconvenient, disruptive and much more expensive subsequently. Will the client occupy the building? Clients who develop to sell or lease may be less concerned with the operating and maintenance costs of the facility which will be passed onto the eventual purchaser or user of the facility. Clients who spend more initially will seek to recover their investment through higher rents or sales price. This approach may be adopted by future oriented private sector clients concerned with sustainability and green building issues. What is the life-span of the building? The shorter the planned life span of the building the less appropriate it is to incorporate robust and durable materials and systems.
Clients who prioritise cost over speed or who require fixed price lump sums will generally experience longer development programmes, as designs must be substantially completed before tenders can be obtained. This process may take a considerable amount of time as careful thought is required to develop and refine the scheme design. The design, in turn, influences the contractors construction methods which determine length of time taken to complete the contract on site.
It is clear that the purpose of a building will have a major bearing on its cost. Housing has a very different cost range to apartments and commercial development. Likewish the cost of providing public amenities such as conference centres, theatres and sports stadia cannot be directly related to the provision of public infrastructure such as hospitals or schools. The cost of each building must be related to its individual design, which may be benchmarked against similar national and international projects.
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.