Procurement using Specification and Drawings
Under this option the Contractor is selected and appointed on the basis of a lump sum bid provided in response to a detailed Specification document, which when read in conjunction with the drawings, defines the scope of work to be carried out as the Contract Works.
The Specification can also include provisional allowances for unforeseen or un-designed work together with allowances included for specialist works yet to be tendered. Measurements and quantities are prepared by the Tenderers to enable them to price the work. Like Schedules of Work, the use and meaning of these provisional sums needs to be described and defined in the invitation to tender documents.
Normally, tendering is in competition with a pre-selected or pre-qualified list of Contractors.
Specification and Drawings are Appropriate for smaller projects such as house extensions and renovations because all Tenderers need to produce their own quantities and also because of the time involved in achieving a sufficiency of the designs to enable the Specification and invitation tender documents to be prepared.
The use this form of procurement is not particularly appropriate where it is likely that change will be required by the Employer after the contract has been started due to the fact that there are no competitive rates under which variation values can be assessed.
The advantages associated with this method of procurement are:
The lump sum price is firm, subject only to variations which may be instructed during the course of the Contract Works.
Client risk in respect of errors in a Bill of Quantities is avoided because the Contractor prepares his own measurements and quantities.
Can incorporate Design and Build and Performance Specified works if required
Disadvantages associated with this form of procurement are:
The design must be well advanced in order to prepare the detailed Specification documents. This procurement route can therefore mean a later site start than with alternative procurement routes.
Give less control of cost when variations are instructed than firm Bills of quantities because of the lack of a defined system of measurement of the building elements.
Tenders are not as easily comparable to each other as is possible with Bills of Quantities, because the tendering contractors may interpret and price risk in the Specification document in different ways.