Cases / Estimating & costing
Estimating & costing

Manage provisional sums and allowances

Handle the parts of a bill the design cannot yet fix - provisional sums, prime cost sums and allowances - kept separate from measured work so each one has an owner and can be drawn down cleanly.

4 steps10 minCost consultancy / QS practiceGeneral contractorDeveloper / client

How it works, step by step

4 steps across the platform - what you do at each one, and why it matters.

1

Find what cannot be fixed yet

Allowances

Go through the scope and list every element the design cannot yet price firmly: undesigned finishes, a specialist package still out to market, statutory connections, a prime cost item.

Allowances screen in OpenConstructionERP: find what cannot be fixed yet

Why: Naming the soft spots up front is what stops them being priced twice or missed entirely. It also tells the client exactly which parts of the number are still to be firmed up.

InIncomplete designScope gapsOutList of sums
2

Set the type and the basis

Allowances

Mark each one as a defined or undefined provisional sum, a prime cost sum or an allowance, then record the basis behind the figure and who owns firming it up.

Why: A defined sum carries programme and preliminaries; an undefined one does not. Getting the type right now decides whether you can claim time and cost when it is finally instructed.

InList of sumsOutBasis and owner set
3

Carry them into the bill

BOQ

Bring the sums into the bill in their own section, clearly separate from measured work, so the tender total shows firm price and provisional money apart.

Why: Kept separate, the sums can be expended and adjusted through the job without disturbing the measured rates. Buried in the rates they become impossible to track or hand back.

InClassified sumsOutSeparate bill section
4

Check for double counting

Validation

Validate that nothing sits in both a rate and a provisional sum, that every sum has an owner, and that the totals reconcile before the bill goes out.

Why: Double counting a package is an easy way to price yourself out of a job; missing it is an easy way to lose money. A quick validation pass closes both traps at once.

InBill with sumsOutNo double counts
Modules

Modules in this playbook

3 / 184 platform modules

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