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ArCo – Ageing Study of Treated Composite Archaeological Waterlogged Artefacts

Archaeological wood artefacts have undergone several deterioration processes in the past decades. ArCo is a conservation project, which combines previous findings on archaeological wood treatments with an insight into its ageing process, in the presence of unstable salts.


Photo from ARC-Nucléart
Archaeological wood sample containing unstable salts. Photo: ARC.

When it comes to preservation of archaeological wood artefacts, conservation scientists are faced with several challenges. Although many wooden artefacts were discovered underground, on the seabed or lake bottoms, where deterioration is limited due to deficient oxygen levels, these waterlogged artefacts were subjected to various chemical changes. The presence of unstable salts in wood, formed during burial or after the application of conservation treatments, is an issue that raises great concern. These salts include iron sulphides, which were formed due to sulphate-reducing bacteria from anoxic waters and metal corrosion in wood, and alum which was used for conservation treatments in the 1850–1950’s. After removal from the burial environment or treatment with alum, these mineral salts can be subjected to oxidation reactions or hydrolysis and cause wood acidification, precipitation of salts and consequent mechanical damage. It is therefore important to neutralize the acidic environment, inactivate metal ions and prevent oxidation of salts, in order to maintain the integrity of such valuable cultural heritage artefacts.


  1. Understand deterioration processes at a chemical level: interactions between wood, consolidation agents and unstable salts

  2. Understand long-term behaviour of treated archaeological wood

  3. Obtain relevant insight on conservation methods: establish a useful guidance tool for future treatments


The project is carried out at five European laboratories and includes archaeological waterlogged wood from ancient ship finds from Norway, Denmark and France. The main tasks are divided into three parts:

  • Sampling: sample wood containing various mineral salts and subjected to different conservation treatments

  • Weathering: age the samples in a climate chamber with fluctuating relative air humidity

  • Characterization: analyse morphological, chemical and physical characteristics of wood samples, before and after artificial ageing



Joint Programming Initiative (JPI) on Cultural Heritage – Joint Heritage European Programme (JHEP) Pilot Call


  • KHM - Museum of Cultural History
  • Natmus - National Museum of Denmark
  • ARC - ARC-Nucléart, France
  • DCCI - University of Pisa, Italy
  • ARCHA - ARCHA laboratory, Italy
Published Oct. 6, 2015 3:40 PM - Last modified Nov. 18, 2020 10:13 AM


Project coordinator

Hartmut Kutzke
Museum of Cultural History

Visiting address

Viking Ship Museum
Huk aveny 35
0287 Oslo