Why one square-foot rate is rarely enough
Two buildings with the same floor area can have different structural loading, wall height, room count, insulation, openings, finishes, services and delivery conditions. A meaningful comparison should separate the building shell, foundation, finishes, services, transport, installation, taxes and exclusions.
Major cost factors
Structural system
Steel grade, frame spacing, loads, corrosion protection and engineering determine structural quantities.
Wall and roof build-up
Panel core, thickness, sheet gauge, boards, insulation, vapour control and junction details affect cost and performance.
Foundation and site work
Ground conditions, slope, drainage, retaining work and access can significantly change work outside the prefab superstructure.
Rooms and finishes
More partitions, doors, windows, wet areas, ceilings, floor finishes and built-in work increase material and labour quantities.
Services
Electrical, plumbing, ventilation, heating or cooling, fire systems and data requirements must be coordinated early.
Transport and installation
Distance, road width, unloading, crane access, worker accommodation and installation duration affect logistics.
Approval and programme
Drawing changes after procurement, urgent delivery and phased work can introduce additional commercial risk.
Recommended budgeting sequence
- Define intended use, location, dimensions, room schedule and required completion date.
- Prepare a concept plan and record floor-to-floor height, openings and service requirements.
- Select a preliminary structural, wall, roof and finish specification.
- Generate a material schedule and apply current reference prices.
- Add foundation, transport, installation, tax, contingency and work by others.
- Request a revised quotation after drawings and site conditions are verified.
How to compare supplier quotations
Check whether each proposal includes the same dimensions, thicknesses, steel grade, panel density, finishes, accessories, transport, unloading, installation, taxes and warranty. A lower total may reflect a smaller scope rather than a better price.