Category Archives: Monument conservation

“Nidaros: The Portland Cement Cathedral” (Baker Memorial Lecture)

This week I attended the international conference “Rediscovering Traditional Mortars” in Trondheim. The conference was hosted by the Nidaros Cathedral Workshop and it was part of the annual conferences organised by the British Building Limes Forum and its Nordic counterpart.

I was lucky to be invited to keep two lectures, one on the experimental lime burning in Hyllestad earlier this year, and the Baker Memorial Lecture during the gala dinner. A very great honour to keep this traditional lecture for more than 230 delegates! I concentrated the lecture on the use of Portland Cement during the restoration of Nidaros Cathedral from 1869 on. Read on to get a glimpse of all the problems it has caused! Continue reading

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Forvitring av kleberstein på middelalderkirker – to videoer

Sist vinter holdt jeg to foredrag om forvitring av kleberstein sett i lys av bygnings- og restaureringshistorie. Det dreide seg om portaler fra norsk middelalder og foredragene ble holdt på «Portalseminaret» i regi av «Domkirken 2025»; miljøet som nå restaurerer Stavanger domkirke og som jeg også er en liten del av. Alle foredragene fra seminaret (og mange andre interessante saker om restaureringen) er nå lagt ut på YouTube.

Kanskje kan mine to foredrag være til hjelp for folk som sliter med å forstå hvorfor kleberstein forvitrer. Veldig mye dreier seg om hva bygningene har vært utsatt for av forandringer og restaureringer gjennom tidene. Men noe av forvitringen kan også knyttes til steinkvalitet, tidligere luftforurensning og ikke minst vann! Rett og slett lekkasjer! Innholdet i foredragene er i stor grad basert på min gamle doktoravhandling “The Stones of Nidaros” fra 1997 og mange artikler om forvitringshistorie, bl.a. “Weathering of soapstone in a historical perspective”. Continue reading

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Experimental archaeology: Building a “classic”, intermittent limekiln and burning marble at Millstone Park, Hyllestad, Western Norway

It took us about six months: Building a cylindrical limekiln of the classic Roman/Medieval type with local materials only – stone rubble and clay. In June this year, we built the firing chamber and filled the kiln with 2.5 tons of local marble, covered the kiln with clay on a layer of spruce branches and started burning. Five days and five nights with much of the local community involved! Here’s an extended photo story of the project – the first of its kind in Norway. The quicklime (burnt marble) will be tested at Selja medieval monastery and other restoration projects in Norway. Thanks to all paid and volunteers and support from The ruin restoration programme of the Norwegian Directorate for Cultural Heritage, as well as Hyllestad Municipality! The project was carried out by The Norwegian Millstone Centre/The Museums in Sogn og Fjordane County. Continue reading

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Happy New Year! With a cavalcade of images from 2015

I wish to thank my clients, partners, colleagues and followers of my website for a fine year! The very best to you all for 2016! With a cavalcade of images, I would like to recapitulate a few 2015 events. First of all, I was finally able to finish my book on the history of stone quarries, which was published jointly by The Restoration Workshop of Nidaros Cathedral and the Geological Survey of Norway. But my work took me to many parts of Norway, from a Mesolithic quartz quarry near Arendal, deep down south, to the fascinating rock art at Alta, far in the north. Though I was not able to visit Egypt last year, I’m still publishing papers on the geoarchaeology of desert quarries down there, together with good colleagues. Read on! Continue reading

Posted in Ancient Egypt, Archaeology, Monument conservation, Norway, Old quarries, Rock art, Ruins | Tagged | Leave a comment

Saltforvitring på kulturminner. Om enkel analyse av salt: Lag din egen kjøkkenlab!

Over er det et bilde av noe du har sett tusen ganger før. Halitt! Vanlig koksalt. Natriumklorid. Ganske enkelt bordsalt. Havsalt! Havet inneholder jo noe sånt som 3,5% oppløst salt. Når pyttene i fjæra får stå i fred noen dager og sola skinner fra skyfri himmel, da lurer saltet seg ut. Sjøvannet fordamper og etterlater seg de fineste krystaller av ren halitt. Sånn laget man koksalt i gamle dager, handlet med det, kriget om det. For uten koksalt kan vi ikke leve. Kanskje fyrte man opp under brede kjeler med sjøvann for å få fordampningen til å gå raskere, kanskje kjøpte man salt fra store saltgruver på Kontinentet. Men prinsippet er det samme: Når saltholdig vann fordamper, da får vi krystallinsk salt. Men hva om du ikke visste at de fine krystallene i fjæra er koksalt? Og hva om du fant noe som lignet på disse krystallene på et ødelagt murmaleri eller en steinskulptur fra middelalderen? Hva gjør krystallene forresten der? Var det de som ødela? Hva gjør du da? Continue reading

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Nidarosdomen og forvitring – sett fra 17 år tilbake i tid

Ganske tilfeldig kom jeg over en utgammel tekst om Nidarosdomen og forvitring her forleden. Det viste seg snart at det var en omtale av min egen doktoravhandling om temaet fra 1998; stødig ført i pennen av Hans Georg Jürgens og publisert i Universitetsavisa i Trondheim. Så leste jeg gjennom. Og fant ut at det meste har aktualitet den dag i dag. For om man googler “Nidarosdomen og forvitring”, så dukker det fortsatt opp helt tullete skremselsbilder om gigantisk luftforurensning som tærer på nasjonal-helligdommen. Nei, forvitringen på Nidarosdomen er nok mer kompleks enn som så.

Så jeg tillater meg å sitereden 17 år gamle omtalen til Hans Georg Jürgens i sin helhet. Den har tittelen:
“Nidarosdomen skranter… Continue reading

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St. Basil’s Cathedral in Moscow – on a cold winter day 25 years ago

I’m getting thousands of my old slides scanned at the moment. Since I’m not doing it myself, I reckoned that the “post-production” and archiving would cost me a few hours’, perhaps a day’s work. I was utterly wrong.

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Impressions from summer fieldwork in Norway

Over the last few weeks I’ve been back in Norway for projects on conservation of medieval castle ruins, as well as on provenance of medieval and more modern building stone. Here are some impressions!*

Posted in Archaeology, Monument conservation, New projects, Norway, Old quarries, Rock art, Ruins | Tagged , , , , , , , | Leave a comment

New York Times: “Egypt or Central Park: Where Does an Ancient Obelisk Belong?”

The issue of bringing Central Park’s Cleopatra’s Needle back to Egypt is still in the media. See this recent video from New York Times on the weathering of the New Kingdom obelisk: …and check out these blog posts of mine … Continue reading

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Cooperation with Norwegian conservation company

An agreement of cooperation has been signed with the Norwegian conservation company “Bakken & Magnussen AS” in Trondheim, Norway. The idea is to expand the competence of the conservation company with services related to conservation science and geoarchaeology. Bakken & … Continue reading

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