How do you compare the cost of two halls with the same floor area?

Specify the use as well. A warehouse for dry packaging, a workshop and a cold store differ in equipment, operating temperature and fire requirements. List external works, drainage and service connections separately. Some of these costs bear little relation to the floor area but still need funding.

Consider two halls of 432 m² each. One measures 18 × 24 m with a perimeter of 84 m; the other measures 12 × 36 m with a perimeter of 96 m. At a wall height of 5 m, their rectangular wall areas are 420 and 480 m² respectively: a difference of 60 m² for the same nominal floor area.

The calculation excludes gables, openings and cutting waste. Nor does it price the frame: spans and the internal layout need separate assessment. It isolates one effect worth checking before choosing between two layouts: increasing the perimeter also increases the wall area.

For illustration, allow about €32.90/m² excluding VAT for wall panels. Before cutting, the additional 60 m² costs about €1,974.28. Labour at roughly €11.12/m² adds €667.36, bringing the difference to about €2,641.65 excluding VAT. The amounts were converted before rounding; they are not a quotation for a particular hall.

A longer perimeter may require more plinth trim and finishing work. Both rectangles still have four corners. Applying one percentage increase to every item misses that distinction; show quantity, unit and rate for each.

Design loads depend on location, geometry and use. The design covers the primary frame, panel supports and connections. Wider frame spacing may reduce the number of frames while changing the requirements for other members. Removing a frame from a sketch does not establish a saving.

Increasing the height adds cladding and changes structural and installation conditions. Fire resistance or acoustic requirements may call for a different core and different details. Recalculate the assembly as a whole rather than comparing panel thicknesses alone.

Compare clear door openings and usable height below the frame. Similar external dimensions can conceal a difference in storage capacity.

Request separate figures for foundations, frame, walls, roof, doors and windows, and floor. The envelope price should state panel quantities, flashings and seals. Establish who unloads the delivery and who pays for equipment hire, fall protection and crew travel.

Record exclusions against each item. Roofing may exclude drainage or service penetrations. Agree how changes in dimensions and additional work will be charged. Compare figures excluding VAT; for a gross comparison, apply the same explicit tax assumption to the same scope.

Resolve gaps in ground conditions, door dimensions, service routes and envelope requirements. List each allowance with its reason. A contingency for earthworks covers a different risk from a provisional allowance for panel cutting; combining them hides the possible source of extra cost.

Update the budget as design decisions are made. Once the frame and cladding schedule are approved, replace estimates with confirmed quantities. Tie payments to deliveries and acceptance milestones so the estimate shows both the final cost and when funds are needed.