Every practice has a version of the same story. A structural detail is questioned two years after handover. Someone produces a drawing. The practice is fairly sure it is not the drawing that was issued, or not the revision that was issued, but proving that means going back through email threads, a document management system that has since been migrated, and the memory of a colleague who has left.
The technical argument is often straightforward. The evidential argument is what costs money.
What the dispute is actually about
Professional liability claims against architects and engineers rarely hinge on whether a calculation was right. They hinge on what was issued, in what revision, and on what date. A drawing that was superseded three weeks before construction started is a very different document from the one that was on site, but on paper they can look nearly identical.
Three failure points recur:
- Revision ambiguity. Multiple revisions circulate simultaneously through consultants, contractors, and subcontractors, and the version on site is not always the version the practice believes it issued.
- Date uncertainty. A title block date records when the drawing was drawn, not when it was released, and the two can differ by weeks.
- Silent alteration. A PDF issued to a contractor can be edited before it is passed on, and nothing in the file records that it happened.
Document management systems help with the first, partly. They do not help at all with the third, and their date records are internal to the practice, which weakens them precisely when they matter most.
What sealing a drawing does
Sealing applies a cryptographic hash, a qualified electronic signature or seal, and a qualified timestamp to the drawing file at the moment of issue. The result is a document that carries its own evidence.
The revision is fixed. The hash covers the entire file. If any element changes, a line, a dimension, a note in the title block, verification fails. The revision that was sealed is provably the revision that was issued.
The date is independent. The timestamp comes from an accredited timestamp authority, not from the practice's own server. Under eIDAS Regulation (EU) No 910/2014 a qualified timestamp carries a legal presumption as to the accuracy of the date and time it records, which means it is not simply the practice asserting its own version of the chronology.
The author is identified. A qualified electronic signature binds the drawing to the individual professional. Where the drawing is issued in the practice's name rather than an individual's, a qualified electronic seal binds it to the firm instead.
The legal position
In Switzerland, qualified electronic signatures are governed by ZertES (SR 943.03). Where a qualified electronic signature is used, Article 14 paragraph 2bis of the Swiss Code of Obligations gives it the same legal effect as a handwritten signature. For practices working across borders, eIDAS provides the equivalent position throughout the EU.
There is a second layer that architects in particular tend to underuse. Architectural drawings are original works and attract copyright protection automatically under the Berne Convention, with no registration required. The protection exists from the moment of creation. What does not exist automatically is proof of when you created a specific design, which becomes the live question when a client reuses your drawings on a second site without a further fee, or when a competitor's scheme resembles yours more closely than coincidence allows.
A sealed and timestamped drawing set establishes the date of creation with third party evidence. That is the difference between holding a right and being able to enforce it.
Fitting it into how a practice actually works
The obstacle is usually workflow, not principle. Practices issue drawings in batches, under deadline, often late in the day, and any step that adds friction to that moment will be skipped.
Sealing sits at the point of issue rather than the point of drawing. The drawing is produced and checked as normal. When the issue sheet is prepared, the files are sealed as a set, which takes the same effort whether it is one drawing or eighty. What the contractor receives looks and opens exactly as before.
Two practical notes. Seal the file you actually issue, not the source file, because the issued PDF is the document that will be produced in a dispute. And seal every revision rather than only the construction issue, since the superseded revisions are frequently what the argument turns on.
What you can check today
Take the last drawing set you issued on a live project and ask what you could prove about it if it were disputed next year. Can you show which revision went out, on what date, and that it has not been altered since, using evidence that does not depend on your own systems and your own word?
If the honest answer is that you would be reconstructing it from email, that is the gap. Any sealed document can be checked using the public validator at swisstrustlayer.com/validate, without an account.
