Pre-Contract Cost Control Cost Plan Purpose/Function Assists the design team in controlling the cost of the design Assists in economically spreading the cost between the elements of the building A tool for analysing and comparing tenders

Cost Planning The process Pre-Contract Cost Control Early cost bracket information Detailed Elemental Cost Estimate Group Elemental Outline Cost Plan Elemental Cost Estimate adjusted to take account of coarse elemental unit quantities Checked Cost Plan Adjusted Detailed Elemental Cost Plan Adjusted Group Elemental Outline Cost Plan Cost Plan Element allowances checked with approximate quantities of specified design information Historic Group Elemental Cost analysis adjusted for Time, Location and Design Features Source: Jaggar D. et al (2002) pp 91

Cost Plan Pre-Contract Cost Control Group Elements Substructure Superstructure Internal/External Finishes Fittings and furnishings Services External works Preliminaries Contingencies Building sub-total

Cost Plan - Detailed Elements Substructure Superstructure Pre-Contract Cost Control Cost Plan - Detailed Elements Substructure Works up to the underside of lowest floor finish including damp proof course (dpc) Superstructure Frame Upper floors Roof Roof structure Roof covering Roof drainage Rooflights

Cost Plan - Detailed Elements Superstructure Pre-Contract Cost Control Stairs Stair structure Stair finishes Stair balustrades and handrails External walls Windows and external doors Windows External doors Internal walls and partitions Internal doors

Cost Plan - Detailed Elements Pre-Contract Cost Control Internal finishes Wall finishes Floor finishes Ceiling finishes Fittings and furnishings Fittings, fixtures and furniture Soft furniture Works of art equipment

Cost Plan - Detailed Elements Pre-Contract Cost Control Services Sanitary appliances Services equipment Disposal installations Internal drainage Refuse disposal Water installations Main water supply Cold water services Hot water services Steam and condensate

Cost Plan - Detailed Elements Pre-Contract Cost Control Services Heat source Space heating and air treatment Ventilating systems Electrical installations Gas installations Lift and conveyor installations Protective installations Fire fighting, lightening protection Communication installations

Cost Plan - Detailed Elements Pre-Contract Cost Control External works Site works Site preparation (clearing, demolition, etc) Surface treatment (roads, pavements, etc) Drainage External services Water mains Gas mains Site lighting, etc Minor building works Ancillary buildings Alterations to existing buildings

Cost Plan In developing a Cost Plan it is necessary to adjust for Pre-Contract Cost Control Cost Plan In developing a Cost Plan it is necessary to adjust for Location Design features and specifications Inflation prior to the start using the relevant tender price indices Projections for future inflation during the construction period Type of contract and procurement route Market conditions A two stage approach Group elemental outline cost plan Detailed elemental cost plan

Assuming 3.5 m building height Pre-Contract Cost Control Design features that can influence building cost Plan shape Perimeter to floor area ratio will affect: cost of external walls per gross floor area foundation cost per gross floor area cost of windows per gross floor area energy cost due to heat loss cost of cleaning cost of painting and decoration cost of service distribution systems e.g. water, electricity, other mechanical systems 100m 50m 200m Example: Perimeter = 400m Floor Area = 10000m2 Perimeter = 500m Wall-to-floor ratio = 0.14 Wall-to-floor ratio = 0.175 Assuming 3.5 m building height

Design features that can influence building cost Pre-Contract Cost Control Design features that can influence building cost Plan shape Upper floors and Roofs Larger spans will require expensive structural roof elements Load bearing internal walls Columns to support the upper floors and roof structures Heavier reinforcement of the upper floors Complex shapes Low labour productivity at site Increased waste of material in terms of cutting waste Where the ratio of perimeter to gross floor area is higher, the cost of the perimeter elements of the roof will be higher Reduced level of competition as only contractors specialised in the construction of such a facility can bid for it, hence contractor’s will price higher.

Design features that can influence building cost Pre-Contract Cost Control Design features that can influence building cost Internal plan (planning efficiency) High circulation area to gross floor area ratio implies Bigger building with higher cost implications Reduced amount of rentable area if it is a commercial property Minimising economic viability of the building Storey height Has influence and hence cost implications on Wall to gross floor area ratio External and internal finishing Vertical elements of services

Design features that can influence building cost Pre-Contract Cost Control Design features that can influence building cost Height (No of storeys) The cost of some elements will increase while others may decrease. (ref attached extract from Morton R & Jaggar D, 1995, Design and the Economics of Buildings pp 208-209) E.g. Greater requirement for lifts and stairways Reduced level of rentable area as a result of bigger stairs and lifts Increased cost of engineering services Higher levels of structural stability to withstand wind loads High levels of life-cycle cost due to maintenance cost of services Lower foundation cost per gross floor area Lower roof cost per gross floor area However the need for high rise buildings despite the cost implications may be due to: High cost of land in inner cities Savings in the cost of infrastructure

Other features that influence building cost Pre-Contract Cost Control Other features that influence building cost Groupings of building Closely linked buildings will save on the external works cost Buildability i.e. the extent to which the design of building facilitates ease of construction Buildings requiring complex construction methods will therefore be more expensive to build. Constructional details Types of Materials used e.g. structural steel or reinforced concrete frame Site characteristics Size and topography Location (accessibility, protection of existing structures, etc)