Architecture / June 23, 2018 /
The payment arrangements adopted on a contract directly affects the level of risk borne by the contractor. Where the contract is let on the basis of a drawings and specification lump sum the contractor assumes the risk for both the quantity and pricing. In lump sum contacts based on bills of quantities and remeasurement contracts the contractor assumes the risk for the pricing only. With reimbursement contracts the client assumes the risk for the quantity and pricing. The payment arrangement, therefore, directly motivates the contractors efforts to carry out the work in an efficient and economic manner. This in turn has a major impact on the final price paid by the client.
In general it can be said that larger buildings with simple, rectangular, regular floor plans and elevations will be less expensive per sq.m. of floor area than smaller, complex shaped, curved or angular buildings. Economies of scale apportion fixed overheads to a larger extent of productive space. Simple setting out and buildable solutions encourage greater plant use and generate higher productivity and less waste. Complex layouts and details are slower to assemble and may involve a number of trades with a consequent greater risk of mistakes and defects. The degree of compartmentation and repetition will also affect the overall cost of the work. New building work is considerably cheaper than work of a repairing nature or work in existing buildings. Single storey structures tend to be more costly than buildings up to three storeys high, beyond which point they become progressively more expensive.