---
id: KB-CN-034
url: https://app.codecontract.io/help/construction/the-designer-questioned-years-later
idioma: en
categoria: sector-construccion
subcategoria: ingenieriacivil
audiencia: usuario
nivel: avanzado
actualizado: 2026-08-13
tambienEn: [es]
relacionados: [KB-CN-022, KB-IU-022]
citadoPor: [KB-CN-035]
---

# The designer questioned years later

_That was calculated eight years ago on certain data and certain criteria. Today somebody asks about it, and only what you filed exists._

**Responde a:** how long to keep project calculations · asked about a project from years ago · which version of the design was built · design documentation and site changes

You signed a design, it was built, and years passed. Today a question arrives: an extension, a change of use, an incident, a review. **Whoever asks does not want to know whether you worked well: they want to know on what data and on what criteria that was decided**, and the answer is not in the design you delivered but in what sits behind it.

## What gets asked and where the answer lives

| The question | Where the answer lives | If it was not archived |
| --- | --- | --- |
| What was designed? | In the delivered design | It usually exists |
| On what input data? | In the annexes and studies | **It is lost first** |
| What criteria were applied? | In the calculation, not the drawing | It cannot be deduced |
| **What was actually built?** | **In the site changes** | **It rarely returns to the designer** |

> [!IMPORTANT]
> **What is lost first is not the design: it is the input data.** The delivered design survives because copies sit in several places. What disappears is the ground investigation they gave you, the flow figures you were handed, the assumption confirmed by email — everything that reached you from outside and on which the calculation rests. And it is exactly what is needed, years later, to explain why what was decided was decided.

## What to archive with ten years in mind

1. **The input data and who supplied it** — With dates. The calculation rests on it, and it was not yours.
2. **The criteria and rules applied** — With their version: they change, and what applied then applied.
3. **What was modified during construction** — It is what separates you from what was actually built.
4. **And which version is definitive** — With several circulating, the question will always be which.

> [!WARNING]
> The specific risk in this position is **being asked about something built differently from how you designed it**. It happens often, almost always for sound reasons taken on site, and it does not always come back to the designer. Years later the question reaches whoever signed, not whoever decided the change. Having on file what was modified, who decided it and when you were told —or that you were not— is the difference between explaining and carrying it.

> [!NOTE]
> For how long project documentation must be retained, what liability reaches the designer and over what periods **is determined by the applicable rules, and settled by your professional body or adviser**. Here we cover the organisational part: what to archive in order to explain a technical decision a decade later.

**How long must it be kept?**

Longer than the project lasts, and your adviser settles the exact period.

**Should I keep data that others gave me?**

Especially that. It is the basis of the calculation and it is not yours.

**What if it was built differently from the design?**

Archive what changed and what you were told. That is what places you.

## Ejemplos

**Questions arrive about a project from eight years ago.**

- Keeps the complete file with its date

→ It is answered from the archive, not from memory.

**The input data supplied by others can no longer be found.**

- Stores what was received from third parties with the project

→ The basis of the calculation still exists.

**Several versions circulate and nobody knows which was built.**

- Keeps versions with dates instead of replacing them

→ You can say what applied at each moment.

**Something was changed on site and never reached the designer.**

- Records what was communicated and when

→ Each party's position is documented.

**The file lives on the computer of whoever signed it.**

- Stores projects outside personal machines

→ One person leaving does not take the archive.

**Documentation must go to a third party without over-disclosing.**

- Controls which documents are shared and with whom

→ What was asked for is handed over, not what sat beside it.