Preliminaries are the costs of setting up, running and closing the site. A flat percentage may miss the staff, welfare or access needed for the planned time and scope.
A cheaper site allowance is useful only if the job can run within it. Can it?
Build Preliminaries In Construction Tenders From The Site Plan
Read the tender duties and price site staff, welfare, plant and security. Check power, water, waste and the tasks needed at the end.
Allow for access, phases and live-site limits. The same trade value can need very different site support on two jobs.
Split Costs By Their Driver
Some costs arise once. Others grow each week or follow a task. Show setup and close-out time as well as the main work period.
A reduced allowance needs a real change in the plan. If a manager is needed for twelve weeks, pricing eight does not create a saving.
Eight weeks may look cheaper than twelve. Does the programme support eight?
- Set up
Price the one-off mobilisation costs.
- Run the site
Link weekly costs to the needed duration.
- Close out
Include clearance, testing and demobilisation.
Use the actual setup, running period and closeout plan to build the allowance.
Check Gaps And Overlaps
Read trade quotes to confirm who provides lifting, access and site help. Count each cost once and keep office overheads on a clear basis.
Test what a longer job would cost. More site time does not alone prove a right to delay costs; the terms, cause and records must support it.
General guidance. Check your signed contract and the job facts. Get legal advice where needed.