Estimating & costing
Check an estimate before you send it
Put a priced bill through the validation rules, clear every warning and error, then export…
3 steps8 minOpen
Cases / Estimating & costing
Estimating & costing
Walk the estimate from Class D to Class A
Say what each estimate was prepared from and which class of the ladder that puts it in, carry the design allowance the class expects separately from risk, roll the cost up by element as well as by trade, and escalate to the mid-point of construction rather than to the day the job finishes.
How it works, step by step
5 steps across the platform - what you do at each one, and why it matters.
1
Say what this estimate was prepared from
Basis of EstimateRecord the documents the estimate rests on and the class of the ladder they put it in, together with what is included and excluded, the market conditions assumed and the reason for the contingency carried. Name the design allowance the class expects, and do not state an accuracy range.
Why: The class is a statement about the documents rather than about the estimator, which is exactly why it is worth writing down. It tells the reader whether they are looking at a number to plan around or a number to commit to, and that is the difference between an estimate that gets superseded and one that gets blamed.
InDesign documents at this stageAssumptions and exclusionsOutBasis document stating the classDesign allowance declared
2
Carry design allowance and risk as separate lines
Allowances & ContingencyCarry the design allowance for the class as its own line, carry the allowance for identified risks as a second one, and write the reason for each beside it rather than in a covering note.
Why: The two answer different questions and only one of them shrinks as drawings arrive. Rolled into a single contingency, the design maturing forces you either to cut a number you should keep or to keep one you should cut, and neither version can be explained to the client without explaining the mistake.
InClass and its design allowanceIdentified project risksOutTwo allowance lines with reasonsA design allowance that can shrink
3
Roll the cost up by element as well as by trade
Bill of QuantitiesSummarise the same cost by building element, so substructure, structure, envelope, internal finishes, services and external works each carry a total and a cost per square metre alongside the trade breakdown.
Why: A client comparing this scheme against the last one compares elements, because trades shift with the procurement route and elements do not. It is also the fastest way to find the line that is wrong: an envelope rate out by a third is invisible in a trade total and obvious per square metre.
InPriced bill by tradeGross floor areaOutElemental summaryCost per square metre by element
4
Escalate to the mid-point of construction
Price IndexApply escalation from a dated index series between the date the prices were built and the mid-point of the construction period, and state both dates on the face of the estimate.
Why: Escalating to the tender date underprices everything that happens after it and escalating to completion overprices half the job. The mid-point is where the average dollar is actually spent, and a reviewer expects to see it, so using it is one fewer thing you have to defend.
InBase date of the pricesConstruction start and finishOutEscalation to the mid-pointBoth dates stated on the estimate
5
Compare the classes and say what moved the number
ReportsReport the newer estimate against the earlier one element by element, separating what moved because the design changed, what moved because the market moved, and what moved because an allowance was released.
Why: When a Class B replaces a Class C the client asks one question, which is why the number changed. An answer split into design, market and allowance is a conversation about the project. A single variance figure is an accusation looking for somebody to attach itself to.
InThe earlier estimateThe current estimateOutVariance split by causeA movement the client can accept
