The idea behind WerkDelta
When a building has a defect, the argument is rarely about whether the defect exists. It is about what it is worth. A diminished-value figure decides real money, and it is contested precisely because, on paper, the number often looks like it appeared from nowhere. WerkDelta is built to remove that suspicion.
The number was never the hard part
Any expert can name a diminished value. The hard part is showing how they arrived at it, in a way that holds up when the other side reads every line. A defensible assessment has to be four things at once: complete, so nothing material is missing; consistent, so the parts do not contradict each other; verifiable, so a reader can retrace each step; and repeatable, so the same inputs always give the same result.
Done by hand, across spreadsheets and prose, that is difficult to keep intact. One changed assumption ripples through the rest, sources drift away from the claims they support, and a later version quietly overwrites what an earlier one said. WerkDelta exists to make the derivation itself the product, not just the final figure.
Four layers, kept apart
The method rests on separating what usually gets mixed. WerkDelta keeps four layers strictly distinct: the findings, the contract and legal profile, the valuation assumptions, and the result. Facts stay in the findings. Legal framing stays in the profile. Judgement stays in the assumptions, where it is visible and can be challenged. Because the layers do not bleed into each other, every part of the conclusion can be traced back to the layer it came from.
Utility is not value
The core of the model is a single discipline: usefulness and worth are treated as two different questions. A target tree describes how well the work still meets its purpose, a utility figure the model calls u. That tree never produces a franc amount. The relation between lost utility and lost value, the model calls it q, is set separately, each time with an evidence level from A to E, a written reason and its sources. Setting q equal to u is possible, but only as a deliberate, labelled choice, never as a default. The diminished value follows as M = P × (1 − q), with a relevant price P that itself has to be derived. Where several defects could overlap, scenarios are compared rather than silently added, and a double-counting warning stays visible in the interface and in the report.
The expert decides, the software documents
This is the line WerkDelta will not cross: it does not produce an objective diminished value at the push of a button, and it does not claim to. That judgement belongs to the expert. What the software guarantees is different and, we think, more useful. The calculation core is deterministic and works to fixed precision, money is never handled as a floating-point number, and the same case always yields the same figure. The expert decides; the software documents that decision and does the arithmetic without drift.
A report you can check
A finished report is an immutable snapshot. Each page carries a shortened SHA-256 checksum of that snapshot in its footer, so a printed copy can be matched against the record it came from. WerkDelta keeps versions instead of editing in place, and a release is tied to the person who signed it. The full case can be exported as a project file: the report, the underlying data, the attachments, an audit trail and a readme with checksums for every file. That export is readable without WerkDelta and does not depend on a licence, so the work outlives the tool that made it.
Built for Swiss practice
WerkDelta is made for construction experts working in Switzerland, in Swiss German, with the formatting and terms the field expects. Accounts use multi-factor sign-in, the audit log is append-only, and each organisation's data is kept separate at the query level. It is a workbench for a specific, careful kind of work. It is not legal advice, and it does not replace a legal review of the underlying claims.
The mark
The logo is a single letter carrying a single idea. A solid W holds an equilateral delta where its centre stroke would be. Delta is the mathematician's sign for a difference, and a difference in value is exactly what the work is about. Ink navy for the structure, a clear teal for the delta: quiet, precise and closer to an engineering drawing than a badge. It says what the product is, before a word is read.