A report on the factors that influence on the accuracy of early-stage construction cost estimate based on a designed construction project scenario.

+ Table 1: Projects that had significant cost variations Designed Project Scenarios Predicted List of Influencing Factors A fitout project on 3 floors of a university building in Parramatta Project 1 final cost varied 55% from the initial cost estimate and the predicted factors that Floor 1, upgrading some of lecture rooms with state of art may have influenced are: communication equipment, acoustic treatment of the rooms and Supply chain issues, delays in delivery of imported materials due to the disruptions caused by Covid improving lighting and climate control Rapid increment of costs of materials due to resorting to have local suppliers on some materials Floor 2, refurbishing of the office spaces, create Covid-compliant, open instead of the cheaper imported options plan workspaces, modern office fitout with furniture, recreation space Labour shortages due to volume of work, increase in labour costs and increase natural light filter. Delays on site due to COVID shutdowns and work stop orders Floor 3: converting unused spaces into medical laboratories with highly . Delays caused by working in a 'live' environment, coordination to deliver works safely depends on specialised equipment the schedules of the users in the building 2 9 story residential and shops mix development: Queen Street, St Project 2 final cost varied 45% from the initial cost estimate and the predicted factors that Marys, NSW may have influenced are: 3,600 m' residential apartments with high quality fitouts; restricted site access and working hour limitations from the city council two basements (1,900m2 total) with car parking spaces plant, labour and material shortages and price escalations . 850 m' up-market shopping mall extended over ground floor including higher bids from contractors due to less competition (caused by shortage of keen tenderers as a food court, shops, leisure areas, kiosks and children play areas result of Covid) landscaped gardens at ground level with water features and fancy disputes between designers and main contractor caused 2 months' closure of the project site lighting supply chain issues, delays in delivery of imported materials due to the disruptions caused by Covid. . . delays on site due to COVID shutdowns and work stop orders 3 Conference and VIP Room Refurbishment - Pitt Street, Sydney Project 3 final cost varied 40% from the initial cost estimate and the predicted factors that CBD may have influenced are: Demolish and Fitout part of the basement area for 2 VIP Room and 1 Design was 60% completed with no detailed drawings for fittings, walls, fire and structural Change Room No specification to some essential items such as Operable Walls and Air-Conditioning system Refurbish Ground Floor Conference Hall with 1 Operable Division Wall Fire Brigade requirements changed from the completion of design to construction completion Demolish walls to large meeting room with 2 Operable Wall Restricted access as the location of the conference room . . Upgrade fire protection system to meet the Fire Brigade requirements . Restricted access and work hours due to other conference rooms needed to be under the operation while refurbishment is under way Labour and Material price increase due to COVID and War, because the drawings were completed at the beginning of COVID