The bases are stated conclusively
Unlike the earlier stages, the standard leaves little latitude here. What must be drawn on includes in particular: The second entry is the one most often missing.
| Basis | Scope |
|---|---|
| Verified invoices | final accounts of the contractors including all variations |
| Evidence of goods and services contributed free of charge | client's own work and materials supplied, for which no invoice exists |
| As-built drawings | the condition actually built |
| Final design documents | status after handover |
The second point is regularly overlooked. Where the client performs work themselves or supplies materials, these must be evidenced within the final cost statement even though no invoice exists. They are costs of the building, even though they were not paid.
The reason is comparability: a project with a substantial element of client-performed work would otherwise yield a benchmark not comparable with fully contracted schemes. Omitting such contributions produces a figure that is useless for the practice's own archive.
Depth of treatment and timing
The final cost statement must be prepared at the third level of the cost structure, and beyond it where appropriate. A coarser schedule does not meet the requirement, even where the total is right.
It is carried out once during the project, after handover and after the final accounts of every trade have been received. That late timing is not convenience but a precondition: only then are all variations included.
Under the HOAI it is anchored as a basic service within work phase 8. It is therefore owed without any need for separate agreement.
Distinguishing deviations by cause
The final cost statement will regularly deviate from the preceding stages, particularly from the pre-tender estimate. The value of the analysis lies in separating deviations by cause rather than showing a single overall difference.
| Cause | Meaning for the analysis |
|---|---|
| Quantity changes | The determination was right, the quantity was not. Establish where the variance came from. |
| Variations from changes of scope | The client changed the scope. This deviation is not a forecasting failure. |
| Variations from unforeseen circumstances | Typical in existing buildings. Points to an inadequate condition survey. |
| Price adjustment clauses | Market movement during construction. Not attributable to the designer. |
| Divergent unit rates | The real test of the quality of the cost determination. |
Only the last row bears directly on the quality of one's own determination. The others are project events. That distinction is the entire purpose of breaking the variance down.
The distinction also matters for liability. An overall deviation of 20 per cent, three quarters of which stems from later client requests, is a different matter from the same deviation arising from unit rates set too low. Without a broken-down analysis that cannot be demonstrated after the fact.
From evidence to benchmark
Four steps turn the final cost statement into a usable benchmark. They are not part of the basic service, but they are the reason the effort pays.
| # | Step | Content |
|---|---|---|
| 1 | Establish and record the reference quantities | gross floor area, gross volume and where applicable the use-specific unit, each under DIN 277 |
| 2 | Record the price date | the quarter to which the account relates; without it the figure cannot be updated |
| 3 | Document the scope | which cost groups are included, net or gross |
| 4 | Record the project characteristics | building type, size class, specification standard, share of technical installations, location |
A figure lacking these four entries is as useless in your own archive as a third-party benchmark without its qualifiers. The system of qualifiers is covered in reading construction cost benchmarks.
The fourth point governs later usability. A benchmark transfers only to a project whose characteristics are known and comparable. The share of cost group 400 is the single most important entry here, because it constrains transferability more than any other.
What the final cost statement is not
Three confusions arise regularly and lead to unusable results. The second is the most consequential, because it is widespread among clients.
| Confusion | What actually applies |
|---|---|
| That it is the final account | the final account is one contractor's document for its own work; the final cost statement assembles all project costs by cost group |
| That it is the basis of fee determination | that role belongs to the cost calculation of work phase 3; a higher final cost statement does not raise the fee, a lower one does not reduce it |
| That it is cost control | control runs continuously between the stages; the final cost statement is the last reference point, not the comparison itself |
The second confusion carries the most consequence, because it is widespread among clients. The expectation that fees follow actual costs does not match the current system and should be clarified early in the project.
Why your own benchmarks beat published ones
A benchmark from your own archive has three advantages over a published one that no dataset can offer. None of them can be replaced by a dataset, however large.
| Advantage | What it means |
|---|---|
| The scope is known | no reconstruction of which cost groups are included or whether the figures are net or gross |
| Comparability of the task can be judged | whoever designed the project knows the particularities that shaped the figure |
| Your own practice standard is reflected | design depth, tendering quality and procurement strategy act on cost and differ between practices |
The effort for the analysis, however, falls at a point when the project is finished and attention has moved elsewhere. That is the practical reason this analysis is so often omitted, and simultaneously the reason practices with a maintained archive are more reliable at early stages than those without.
The cycle closes
The final cost statement closes the cost planning of one project and opens the cost determination of the next. The cost framework and cost estimate of a future scheme rest on benchmarks, and the best source for those is your own completed experience.
The final stage is therefore also the precondition for the quality of the first. The early stages are covered in cost framework and cost estimate.
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This article reflects the position at the date of checking and serves professional orientation. It does not constitute legal advice and does not replace assessment of the individual case.