Provenance
Every number can show its working
Pick any figure in an issued bill and walk backwards: the rate it used and which library release that rate came from, the measurements that produced the quantity, the drawing and revision those measurements were taken on, and who changed what along the way. There is no figure in the system without that chain.
Why it matters
The question always comes eventually
Nobody asks where a number came from while the job is going well. They ask during a final account, in an adjudication, or when a client's own surveyor disagrees — typically about work measured eighteen months earlier by someone who has since left the firm.
Spreadsheets forget
A cell holds a value. It does not hold the drawing it was measured from, the revision that drawing was at, or the rate basis in force that month.
Files drift apart
The bill, the marked-up PDF and the rate schedule live in three places and are updated at three different times. Reconstructing the state they were in together is guesswork.
Memory is not evidence
"I remember we allowed for that" is not a position you can hold under scrutiny, however true it is.
The cost is asymmetric
Being unable to evidence a figure does not just lose that figure. It undermines confidence in the whole account.
The chain
From a report figure to a line on a drawing
These are explicit references in the database, not a description of how the numbers relate. Following them is a query, not an investigation.
- The report figure
- Reports are generated from the same engine that renders the screen, so a printed total and an on-screen total cannot disagree. Issued documents read a snapshot taken at the moment of issue.
- The bill line
- Each line records its rate, its quantity and the build-up beneath it — the labour, plant and material components that compose the rate rather than a single typed figure.
- The rate basis
- The rate resolves through your firm's library at the release the project pinned, so it reproduces the same figure regardless of how the library has moved since.
- The measurements
- Lines link to the specific measurements that produced their quantity. One line commonly draws on several; each is individually addressable.
- The geometry
- Every measurement stores its shape in the drawing's own coordinate space, with the page it was taken on and the scale in force at the time.
- The drawing revision
- Measurements belong to a session against a specific uploaded document at a specific revision. Superseding that drawing flags every measurement taken on it.
On screen
Open the evidence, do not reconstruct it
The chain is not only queryable in principle. A bill line opens an evidence view showing the drawing it was measured on, the geometry drawn over it, the scale applied, and the quantity that geometry produces checked against the quantity stored.
Line evidence sheets
Produce a document for a bill line or a schedule line showing its measurements and the drawing extracts behind them — for a client, an auditor, or your own file.
Takeoff audit report
Every measurement in a session with its geometry, scale basis and derived quantity, as an issued document.
Rate build-up report
The full composition of a rate — each labour, plant and material component with its own source — rather than the single figure that appears in the bill.
Measured against stored
The evidence view recomputes the quantity from the stored geometry and shows it beside the quantity of record, so a discrepancy is visible rather than latent.
The record
Nothing is deleted, and nothing is edited away
An audit trail only works if it cannot be quietly tidied. The database is arranged so that the application — every route, every job, every integration — is structurally unable to remove history.
Append-only audit log
The application's database role holds insert and select permissions on the audit log and nothing else. It cannot update or delete a row, because the permission to do so was never granted.
Soft deletion throughout
Deleting a project, an estimate or a measurement marks it inactive and removes it from view. The row and its history remain, and a deleted project keeps its variations and reports in the firm's record.
No cascading disappearance
Removing a parent never silently removes its children. Anything that genuinely needs to cascade does so explicitly, with its own entry in the log.
Issued means issued
Issuing an estimate snapshots it and locks it. Later work happens on a new version; the issued figures stay exactly as the client received them.
Drawing revisions
A superseded drawing does not silently invalidate a bill
Upload a new revision and the measurements taken on the previous one are flagged as stale. The estimate cannot be issued until someone has looked at each flag and accepted it. Quantifiable does not re-measure the new drawing for you — it makes certain that nobody issues against an old one without knowing.
Client side
The client's half of the record
Provenance runs past the point of issue. What a client was sent, when they opened it and what they decided is recorded on the same terms as everything else.
Decisions are append-only
Acceptances, rejections and change requests are recorded as events. A later decision adds to the history rather than replacing what came before it.
Views are logged
Shared documents record who opened which page and when, against short-lived access tokens rather than a link that circulates indefinitely.
Comments sit on the line
Client queries attach to the specific bill line they concern, so a disagreement is anchored to a figure instead of buried in an email thread.
Shares are snapshots
Sharing an estimate captures the version shared. Continuing to work on the estimate cannot alter what the client is looking at.
Being precise
What this does and does not guarantee
The audit log is append-only because the application's database permissions make it so, and a test suite proves it. That is a strong guarantee against every route, background job and integration in the product. It is not a cryptographic one: it does not defend against a database administrator with direct credentials, and data erased under a valid Article 17 request is genuinely erased, through an audited pipeline built for exactly that purpose. We would rather describe the guarantee accurately than sell you a stronger word for it.
Build an account you can defend
Measure on the drawing, price from a versioned library, and issue documents that can still explain themselves two years later.