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Saturday, August 12, 2017

Preventative Conservation Workshop 2017 Part I: Outdoor Marble Sculpture

During June 2017, aspiring conservators from around the country attended a 2 week intensive preventative conservation workshop at Staatsburgh.  This was the second year that the workshop was held at Staatsburgh with sponsorship from The Foundation for the American Institute for Conservation along with funding from the National Endowment for the Humanities.  The workshop taught in-depth methods of caring for many different types of collections. Participants gained insight into artifact conservation and the conditions that cause deterioration. After the workshop, several of the participants wrote blog entries about their experience and a specific aspect of the workshop.

NYS Bureau of Historic Sites Furniture Conservator, David Bayne, organized this workshop to occur at Staatsburgh collaborating on its organization with Independent Conservator Cathy MacKenzie.  Several conservators participated in the workshop's instruction including  Kirsten Schoonmaker from the Shelburne Museum, Valentine Talland formerly from the Isabella Stewart Gardner Museum, and Michelle Smith currently spending the summer at the National Library of France.

Part I in this series of blogs is by Ruthie Rolfsmeyer.  Ruthie is a conservation technician who has been contracted to work with concrete and wooden sculpture folk art environments in Maine, Georgia, and Wisconsin. She has also done conservation work on indoor murals in Idaho and Minnesota. Her degree is in Fine Art and Graphic Design with a minor in Art History, and she is continuing her education through courses in chemistry and Italian.

Workshop participant and blog author, Ruthie Rolfsmeyer



Neither snow, nor rain, nor heat, nor gloom of night stays these guardians from their appointed grounds.

Just as the interior of Staatsburgh State Historic Site was carefully designed, so too were the grounds. Today, much of the original landscape architecture is obscured by time. Remnants of the past such as a pair of copper beech trees dot the lawn between the home and the Hudson, but the trees lining the river have grown to obscure the view.  As part of this elegant landscape, marble sculptures could transform the surrounding land into an extension of the mansion. These works of art were likely chosen by Mrs. Mills to dazzle guests. Her visitors would take in the views of landscape and outdoor sculpture before entering and after leaving the mansion in addition to the time spent outdoors enjoying the country life. Like an aperitif and digestif surrounding a meal, the marble sculptures offer pleasantries to the palate that are subtle, yet essential to the experience of the mansion.

Diana statue

To the east, two large stone urns frame the house from the front lawn, signifying an intellectual interest in ancient art.* To the northeast, Diana, Roman goddess of the hunt, poses with her faithful hunting dog. To the northwest, a goddess in classical robes stands facing away from the river.* There is currently a parking lot between the two female figures, but historically there were more trees dotting the landscape near the statues.

Goddess on the lawn

Mrs. Mills chose these sculptures as some of the first and last things to be seen on her property. Of course these faithful guardians aren’t true women, but sculpted blocks of marble, possibly mined from nearby marble quarries such as that owned by Dutchess County’s local South Dover Marble Company.  Marble is a crystalline metamorphic rock, composed mainly of calcium carbonate. Other minerals can add a variety of colorations, but the most desirable marble for carving is pure white. It is what limestone turns into after millions of years of heat and pressure. Since antiquity, it has been valued for its translucency, which so nicely mimics that of human flesh. It is also fairly soft and easy to carve—about a 3 rating out of 10 on Mohs Hardness Scale. During Mrs. Mills’ time, marble sculpture was very fashionable and would dot the landscape of many country homes of the era.  

Since these sculptures were placed out in the elements, it may have been presumed that they would take on a certain rustic weathered look. It could be that was part of Mrs. Mills’ desired aesthetic, but it is also possible that they were covered and protected during the harsh winter months. Certainly today they take on a very natural look, all dirty and fuzzy with biological growth and surface corrosion. Unfortunately, the effects of time have also caused destruction and at some point, measures must be taken to conserve these sculptures before they crumble or topple over.

NYS Bureau of Historic Sites staff repositioning the repaired base of the draped goddess statue in 2015


Bureau of Historic Sites Architectural Conservator, Erin Moroney, and Staatsburgh staff re-mounting the draped lady after plinth repair in 2015

The elements have proven to be both physical and chemical agents of deterioration. The expansion and contraction of water molecules as they freeze and thaw within the pores of the stone can cause cracking or “spalling” (detachment of large flakes). Some major cracking can be seen on the base of the robed goddess figure, which is most susceptible to “rising damp” (moisture absorbed from the ground through capillary action). “Frost heave” (expansion and contraction of the ground) can also cause subsidence of the ground around or under a sculpture, leaving it susceptible to collapse.

Salt damage can occur from road salts used to de-ice the parking lot in winter. Depending on RH (Relative Humidity), the salt fluctuates between crystallization and dissolution, and when salt sits on the surface of a marble sculpture it can react with the calcium in the stone to weaken the surface. This often results in a slightly pock-marked appearance. Salt efflorescence occurs when salts dilute in water and move from inside the porous stone to the surface, causing the stone itself to weaken and resulting in a powdery white surface residue.

Rain, especially acid rain, can also play a role in surface corrosion. Marble and limestone etch very easily when exposed to acids such as those in acid rain, which makes the sculpture look dull and fuzzy. This fuzziness is actually little bumps, which collect dirt and spores and become home to fungi, lichen, algae, and moss.

Many historic homes choose to keep these biological signifiers of age. Sometimes cleaning biological growth, such as lichen or algae, from a sculpture can actually destabilize the surface and cause more loss. However, some plants need to be carefully removed. Moss holds destructive moisture to the surface, and ivy or tree roots can badly damage a sculpture through sheer force.
Metals pins show a possible repair on the Diana statue.
                                             
“Inherent vice” refers to issues caused by the way something was built or the materials it was built with. For instance, metal pins were inserted to the sculpture of Diana (possibly as a repair) and have rusted, expanding and cracking the surface. Poor drainage or an insubstantial base can also cause damage.  Inherent vice of outdoor sculpture also includes security issues. Theft and vandalism are always of concern. Ways to combat this include: lighting, fencing, and security cameras.

The sculptures outside the mansion at Staatsburgh face the elements and time in ways indoor art never does. The fundamental nature of preserving outdoor art seems so different than that of objects in light, temperature, and humidity controlled environments. Location and environment are part of the art itself, and acknowledging this loss of control is an important step toward thinking about ways to protect outdoor sculptures.

Preventative conservation is about avoiding future damage. Groundskeeping measures can include protecting the sculpture when mowing the lawn or salting the parking lot. The goddess figure is surrounded by caution tape, which is a good precautionary measure since the base is so badly damaged. Over winter, museum staff could use straw insulation and crate the sculptures to avoid moisture and extreme temperature fluctuations. Another method of insulating the sculptures is to wrap them with polyethylene, perforated at the bottom. Cleaning, if deemed necessary, is best left to a professional conservator.

Though the neoclassical beauties gracing Staatsburgh are out in the elements, they are just as important to the gestalt of the whole environment as any other piece. Stone is so old and primal, so intimately tied up with human evolution. A piece of marble once carved and polished holds within it reflections of who we are, were, and will be. Perhaps Mrs. Mills felt this way as well.


*The urns and the goddess are currently in storage because the base underneath each was no longer stable.  Once those have been repaired, the statues will return to their original locations.




Bibliography

Cami, Josepmaria T. & Santamera, Jacinto C. Sculpture in Stone, Barron’s, Hauppauge, NY, 2000

Mine and Quarry. The Marble Industry in New York State. Mine and Quarry Vol. 1, No. 4, Feb 1907, pp. 95-101. http://quarriesandbeyond.org/pdf/marble_industry_in_new_york_state-mine_and_quarry-feb_1907.pdf

Price, Monica T. The Sourcebook of Decorative Stone: An Illustrated Identification Guide, Firefly Books, Buffalo, NY, 2007

Proudfoot, Trevor. (2011). Outdoor Stone. In The National Trust Manual of Housekeeping: Care and Conservation of Collections in Historic Houses (The National Trust) pp.587-593

Wheatcroft, Andrew, ed. Science for Conservators: Vol. 1 An Introduction to Materials, Routledge, London, 1992

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