The role of Quantity Surveyors and Cost Managers is to establish the overall project budget, and then to ensure that projects are planned, designed, procured, and delivered within this budget.
Rough Order of Magnitude estimates (ROM) and Concept Stage Estimates are usually developed during the Pre-Development and Due Diligence stage, and are used to inform feasibility studies, financial models, and business proformas in order to make a "Go/No-Go Decision".
If you are in the process of developing a ROM or Concept stage estimate, try to obtain the following information from your Client and/or Design team:
1. Program areas (by building / floor / function / etc.)
2. Massing and blocking diagrams
3. Floor plans / test-fit drawings / building elevations
4. Site plans
5. Design renderings
6. Basis of design (BOD) / Design Narratives
7. Overall master project schedule
8. As-built drawings
9. Procurement and pricing strategy
There will be situations where you will be able to obtain some or most of the above, and there will be other instances, where you would hardly obtain a "back of the napkin" sketch, so be prepared!
It is also critical to account for the following to ensure a robust and comprehensive estimate:
1. Building design economics
2. Site conditions
3. General Conditions / General Requirements / Preliminaries
4. Market conditions
Finally, please include the following appendices in your estimate to ensure a clear audit trail, and most importantly, have a "page-turn" session with your Client and the Design team to ensure that everyone is on the same page:
1. Key scope assumptions
4. Marked-up drawings
Any other suggestions? Please share in the comments section below!