The document outlines an architectural conservation project for the facades of the Royal Palace of Stockholm. It summarizes the multi-step process including a preliminary study to assess damage, a pilot project to test restoration methods, and plans to fully document the facades using laser scanning and photogrammetry. The project team aims to preserve authentic materials while following ICOMOS guidelines through extensive research, testing, and continuous evaluation before finalizing a long-term maintenance plan for the historic palace facades.

1. INTRODUCTION TO THE ARCHITECTURAL
CONSERVATION PROJECT FOR THE
FACADES OF THE ROYAL PALACE OF
STOCKHOLM
Heymowski A.a, Günther L.b, Myrin M.c, Andersson E.a, Hägnefelt U.d, Valanis A.d
a HOS Arkitekter AB, (andreas.heymowski, elias.andersson)@hosark.se, Sweden
b National Property Board of Sweden
c Tyréns AB, Sweden
d Norconsult AB, Sweden

2. The Royal Palace of Stockholm
Style: Baroque
Built: 17th century
Architect: Nicodemus Tessin
42,000 m2 total area
1430 rooms (closets, basements etc)
972 windows
28 free standing statues
717 balustrade pieces
28,000 m2 total facade area

3. The facades of the Royal Palace
Façade Materials
9500 m2 stone facade Sandstone (Gotland & Roslag)
11,000 m2 plaster Plaster
7,500 m2 windows and doors Tin, Copper, Iron
28,000 m2 total facade area Wood, Glass

4. Examples of stone decay

5. The project step by step
2005 Detachment of a piece of decorative 2010 Project Directive
sandstone from the façade formal declaration of commence
of action and official terms for the
project entitled:
Long-term maintenance of facades
Software engineering; investigation,
2006 Maintenance program guidelines, pre-planning
i.e. determination of the actions
required for the preservation of the 2011 Pilot Project
entire palace investigation of practical aspects
2009 Preliminary Study and guidelines and specifications
investigation into the condition of for the implementation of the full
the facades and suggested coarse of façade work
action by means of a dedicated
project

6. Past projects for the restoration of
the facades
1697 – Start of construction
1760 – Tessin’s Death
1830 – Completion of construction
Extensive stone Stone work and
restoration, stone conservation of
replacement and Work on the all of the façade
Partial replacement of
use of oil solutions façade plaster windows
the sculpted stone

7. Connection to the ICOMOS guidelines
Challenges:
• plethora of parameters and aspects
• non-linearity in the decision-making process
• extensive testing, evaluation and continuous update of processes in
order to establish a concrete plan for remedial measures
The applied approach :
Maintenance program: Establishment of clear targets and definition of
values and objectives of the program,
Preliminary Study: Completion of the required investigation and
research, to determine standards, requirements
and processes
Pilot Project: Implementation, evaluation and potential update
of the proposed methods for remedy and control.

8. Values and Objectives of the program
Authenticity of material
Identification and preservation of the original stone façade to the
greatest extent possible
Shape integrity
it cannot be allowed to let the artistic and architecturally significant
elements wither to the point that the shape is lost
cases of conflict
the form's authenticity and fidelity to Tessin's ideas is more significant
Decisions
should be made on a case to case basis in order to preserve the
authentic material to the greatest possible extent

9. The Preliminary Study
“the most mature and concrete part of the project so far”
“qualitative assessment of the structure”
CONTENT
- Research carried our regarding:
 the construction of the palace
 past trauma and previous maintenance programs
 structural modifications
 changes of use
-Inventory activities
 detection, classification and evaluation of visible damages
(structural damages and irregularities) and decay of
materials

10. The Pilot Project
Duration: February 2010 – end of 2011
“quantitative assessment of the structure”
CONTENT
 the investigation of the structural behavior of the Palace
 actual assessment of structural damage
 Investigation of material decay
 decision regarding appropriate remedial measures
 geometric documentation of the palace

11. Goals of the Pilot Project
 Selection of appropriate substitute materials
 Criteria for the choice between the conservation or replacement of
pieces
 Non-invasive methods of intervention (modern or traditional)
 Standards and requirements of the geometric documentation process
(accuracies, equipment, deliverables)
 Methods for the assessment of the structural behavior of the structure
 Requirements for monitoring applications
 Frequency and nature of documentation processes
 3D recording, modeling and printing methods
 Quality measures and reports

12. Project Team
The National Property Board of Sweden (owner of the palace and
manager of the project)
Prof. Andreas Heymowski (the palace architect)
HOS Arkitekter AB (historical and architectural investigation, production
of drawings.)
Tyréns (stone restoration , design and a structural engineering)
Norconsult AB (acquisition of laser scanner data and production of
orthophotos)

13. Outlook of the entire project

14. Geometric documentation of the facades
-Terrestrial laser scanning
-Image acquisition
-Pointcloud drawings
-Orthophotos
-Line-drawings

15. Data Acquisition

16. Pointclouds and line-drawings

17. Pointclouds and line-drawings

18. Pointclouds and line-drawings

19. Photogrammetric processing

20. Orthophotos
Orthophoto scale 1:20 pixel size: 2.5mm

21. Orthophotos and point clouds

22. Completion of line drawings

23. Completion of line drawings

24. Comparison to old drawings
Old drawings
New drawings
differences up to 35 cm

25. Orthophoto drawings

26. Restoration plans

27. Conclusions & Future work
Currenlty
Overview of the processes of research, documentation and decision making
for a large architectural heritage conservation project in conjunction to the
ICOMOS “Recommendations for the analysis, conservation and structural
restoration of architectural heritage”
An example of the steps a team may follow from research to implementation
Future work
Completion of the pilot project
Development of a concrete plan for the entire project
Information management

28. Thank you for your attention