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

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

The facades of the Royal Palace

9500 m2 stone facade 11,000 m2 plaster 7,500 m2 windows and doors 28,000 m2 total facade area

Façade Materials Sandstone (Gotland & Roslag) Plaster Tin, Copper, Iron Wood, Glass

Examples of stone decay

2010 Project Directive formal declaration of commence

of action and official terms for the project entitled:

2011 Pilot Project investigation of practical aspects

and guidelines and specifications for the implementation of the full façade work

The project step by step

2005 Detachment of a piece of decorative sandstone from the façade

Long-term maintenance of facades Software engineering; investigation,

guidelines, pre-planning 2006 Maintenance program i.e. determination of the actions

required for the preservation of the entire palace

2009 Preliminary Study investigation into the condition of

the facades and suggested coarse of action by means of a dedicated project

Past projects for the restoration of the facades

1697 – Start of construction 1760 – Tessin’s Death 1830 – Completion of construction

Partial replacement of the sculpted stone

Extensive stone restoration, stone replacement and

use of oil solutions Work on the

façade plaster

Stone work and conservation of all of the façade

windows

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.

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

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

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

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

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)

Outlook of the entire project

Geometric documentation of the facades

-Terrestrial laser scanning -Image acquisition -Pointcloud drawings -Orthophotos -Line-drawings

Data Acquisition

Pointclouds and line-drawings

Pointclouds and line-drawings

Pointclouds and line-drawings

Photogrammetric processing

Orthophotos

Orthophoto scale 1:20 pixel size: 2.5mm

Orthophotos and point clouds

Completion of line drawings

Completion of line drawings

Comparison to old drawings

differences up to 35 cm

Old drawings

New drawings

Orthophoto drawings

Restoration plans

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

Thank you for your attention