In this article we explain what each one is, the difference between them, why they are considered together and what purpose they serve in practice—clearly and without drowning in jargon.
1) Why is a single project not enough?
In historic buildings the answer to "what is there now?" is not enough on its own. You also need:
- What was this building like in the past?
- What has changed over time?
- What is original and what was added later?
- What evidence should today's intervention be based on?
Any implementation done without answering these questions becomes guesswork. That is why the project set has three parts:
First survey → then restitution → finally restoration
This order cannot be changed.
2) Survey: The document of the building as it is today
What is a survey?
A survey is the measured, observed and documented transfer of the building's current physical state into drawings. There is no interpretation; what is drawn is what exists, not "what should be".
What does a survey include?
- Plans, sections and elevations
- Dimensional irregularities in the building
- Wall thicknesses, level differences
- Material types (stone, brick, timber, etc.)
- Cracks, decay, deformation
- Later additions
- Photographs and, where needed, 3D documentation
Why is the survey critical?
The basic data for restitution and restoration is the survey. Wrong or incomplete survey → wrong project → wrong implementation. Work done "by eye" on site will always cause problems in the survey.
The survey is the building's identity card.
3) Restitution: A scientific view of the building's past
What is restitution?
Restitution is the work of reconstructing the building's past state on the basis of documents and evidence. The critical point: Restitution is not "fantasy"; it is a scientific hypothesis.
What sources are used?
- Archive photographs
- Old maps and plans
- Foundation records, written documents
- Inscriptions
- Comparisons with buildings of the same period
- Traces on the building (door openings, window openings, material differences)
What do restitution drawings show?
- The building's past plan layout
- Blocked or lost openings
- Parts added or removed over time
- Historical changes to the façade and roof
In most restitution projects: Parts with certain evidence are shown clearly; parts involving assumption are distinguished with different line types or notes.
Why is restoration not done without restitution?
Because what to conserve, what to remove and what can be completed can only be decided with knowledge of the past.
4) Restoration: The intervention turned into a project
What is restoration?
Restoration is the project that shows how to intervene in the building in the light of survey and restitution data. At this stage "what will be done" becomes clear.
What does the restoration project include?
- Original elements to be conserved
- Building parts to be repaired
- Strengthening decisions
- Parts to be completed (with documentary evidence)
- Position and language of new additions
- Material and implementation details
- Limits of intervention
Restoration is not refurbishment
This is the most common confusion.
- Refurbishment: Remove the old, put in the new.
- Restoration: Understand the old, conserve it, intervene only as much as needed.
So restoration projects are not prepared with a "make it like new" logic; they do not erase the building's history and aim to preserve historical traces.
5) How do the three projects work together?
These three are like different chapters of a single story:
| Stage | Question it answers |
|---|---|
| Survey | What is the building like today? |
| Restitution | What was the building like in the past? |
| Restoration | How should we intervene in the building? |
If you skip one:
- Restitution without survey → assumption without basis
- Restoration without restitution → historical blindness
- Project without restoration → implementation uncertainty
6) In which buildings is this trio required?
Generally:
- Listed buildings
- Monumental works
- Historic mosques, churches, inns, baths, pavilions
- Buildings in conservation areas
- Institutional and public restorations
In some special cases the scope may be narrower; but for serious restoration work the three-part set is standard.
7) The most common problems on site
- Survey drawings not matching the building exactly
- Restitution not based on enough research
- In the restoration project, authenticity being forced for "easy implementation"
- Gap between project and implementation
- Weak site supervision
Most of these problems stem from the project set not being treated as a whole.
8) What does this set mean for the client?
For a client, the survey–restitution–restoration set:
- Is the legal and technical safeguard for the building
- Keeps the process under control
- Reduces the risk of unexpected implementation
- Provides clarity before institutions and boards
- Documents the justification for interventions on the building
This set is the written answer to "what did we do, and why?".
9) Conclusion: Correct restoration starts with the correct project
Survey, restitution and restoration are not alternatives to each other but complements. Any implementation done without these three stages properly in place serves only the present of the building, not its history.
Yet historic buildings are the responsibility not only of today but of the past and the future.