Mary@MaryBrush.com     restorechic@mac.com     www.marybrush.com

  November 5, 2005      

The Laboratoire  de Recherche des Monuments Historique (LRMH) Champs sur Marne is a scientific laboratory specializing in all elements of existing buildings. Every day was an intense lesson in the chemical and molecular properties of everything from stained glass to wood, concrete to steel to stone. 

The LRMH houses a ‘lithoteque’,  a stone and marble library.  Samples of every stone found or quarried in France is on file and catalogued for physical properties.

Experiments in stone include a 10 year study on five types of stone, each treated with sealant or protective chemicals currently available to the construction industry.  These were then placed at five sites throughout France and monitored for ten years.  The samples are now to be analyzed for the effects of urban : rural: industrial pollution and climate changes on both the stone and the potential for protection. 

Another experiment in stone and metal involves a  study on the long term effects of both the metals and the mortar used in the anchorage of stone. 

Stone samples are sent to the LRMH by the Architects en Chef for identification of the stone and possible location of the quarry, and then for an analysis of its physical properties and options for cleaning.  It is at the LRMH where advancements in micro-gommage and laser cleaning of stone were first developed and prepared for the construction industry.

Stained glass windows are also sent to the LRMH for analysis of the pathologies at work on the glass, lead, and restoration options.

Stained glass windows  were often removed from the churches in times of war for their protection.  Their storage methods and locations have effects on their current conditions.  Fires in the churches or as in the case of Amiens Cathedral - in the storage location, also effect the condition of the glass, the leading, and whether the glass can be restored.

Aging experiments are performed on copper and steel, wood is analyzed for its physical properties, age analysis, and also for the animals that exist  in the wood and the options for removing them without harming the wood or its finishes.

Experiments in concrete analyze the original components of a building’s concrete mix, the causes of its deterioration - chemical reactions within the concrete or with the metal reinforcing, and then propose theories for its repair, consolidation or replacement.

The second week I attended a stone conference with several of the stone experts of the LRMH.  I was one of the few architects at the conference where most attendees were geologists, historians of specific buildings tracing the stones of construction to the original quarries,, and historians of quarries, and a compagnon stone carver.  The conference took place in a former quarry, now champagne cave - hooray.  End of session social sessions each day were lovely as champagne was the aperitif of choice.

The conference did include site visits to village churches in the region.  It is amazing to see a church and its stones through the eyes of a compagnon, or a geologist, or a scientist.  Each sees the traces of the tools used to form the stone, the fossils within the stone, or the physical properties of one compared to another.

The LRMH is a  state supported lab, so it is both affordable to use for the historic monuments of France, but with that it is also very popular.  Science takes time.

The projects in the laboratoire include paint analysis of the frescos of the Palais des Papes in Avignon, and an analysis of the  consolidation and cleaning processes.   Wood from roof structures, medieval facades, or even  gold leaf adorned furniture is at the LRMH for consolidation and irradication of insects.

The resource of the LRMH is impressive and the vast amounts of knowledge collected within its facilities is extra ordinary.  It was a pleasure to receive such an intense education from them.