State to monitor humidity levels at the Statehouse
By Art Edelstein
Correspondent | August 25,2013
Jeb Wallace-Brodeur / Staff Photo
Curatorial intern Thaddeus Gibson of Montpelier checks a humidity monitor in the Cedar Creek Room of the Statehouse. It is one of five placed in the building.
MONTPELIER — The Statehouse has suffered fire in the past, but today a potential problem lurks from high humidity.
According to State Curator David Schutz, this summer’s heavy rains are worrisome. The heavy precipitation exposed a potential problem in parts of the building that could lead to damage to the collection of paintings and other important historical artifacts that make up what many see as a priceless state collection.
“We invested in humidity monitors in discrete places to record data,” he said, pegging the cost at “a couple hundred dollars.”
Schutz said he is always concerned about humidity and temperature levels in the Statehouse, which houses many portraits of former state leaders, furniture dating back over a century, and other valuable items. But this summer has been different.
“A baseline I use is if you are comfortable, then your collections are comfortable,” Schutz said. “This year the Statehouse has suffered from excessive humidity and there were definite days when I felt the humidity.”
Five meters placed in the building read temperature and humidity, making it easy to track levels daily. Data collection began this month.
“We’ve never had a good baseline to understand the fluctuations in humidity,” Schutz said.
Humidity has been a problem, agreed Robert Rea, director of facilities for the Department of Buildings and General Services, which oversees the Statehouse and other state buildings.
According to Rea, the Statehouse is 90 percent air-conditioned.
“The problem is why are we seeing higher levels of humidity than in past years?” he said.
Humidity in the building has not been previously measured. In the initial eight days of monitoring this month, humidity levels were in the 50 to 60 percent range. Rea said an optimal level would be 40 to 50 percent. The uncomfortable range lies at 65 percent and higher.
Potential damage from high humidity at the Statehouse involves fluctuations in humidity levels between summer when it rises and winter when it drops, Shutz said.
Humidity affects wood and even paint on canvas. From a preservation perspective the fluctuations often cause damage.
“It’s best to keep things stabilized,” he said.
This summer’s high humidity has Schutz concerned.
“There is an acceptable range of humidity I have assumed we are within,” he said, “but I am beginning to worry this year with the excessive wetness that built up inside long after the outside temperatures have modulated.”
While the painting collection appears undamaged at this point, Schutz said those most susceptible to damage have paint that is not bonding to the canvas as it once did.
“Any old painting has some brittle areas and is vulnerable to damage,” Schutz said. “We are not yet able to state that damage has occurred, but a bit of an alarm bell has been sounded and so we are collecting information.”
He added, “We might have to make the case this is something to worry about.”
The state has insured everything of value in the Statehouse, but Shutz said it’s next to impossible to value the artwork and historic items. The collection, he said, “is fully insured for what the market fully understands.”
Measuring humidity levels at the Statehouse and other state buildings may be necessary to assure the comfort of those inside and important objects that could be damaged if humidity levels rise as predicted by meteorologists.
Mark Breen, senior meteorologist at the Fairbanks Museum in St. Johnsbury said nighttimes are warmer in both summer and winter in the past 10 years due to a rise in humidity with average precipitation “climbing in this same decade.”
The problem may not be related to global warming, he said, but it may be specific to the Northeast.
Rising humidity levels were also detected in the late 1800s in Vermont, Breen said. As for today’s levels, he was not sure if they would continue rising, but said humidity in the region “may be reaching a higher plateau.”
He could also sympathize with Schutz about preserving the integrity of the Statehouse collection.
“I work at the Fairbanks Museum with a large collection,” Breen said. “It’s important in terms of the collections to improve the air-exchange and humidity-control systems.”
While there is not yet enough data to conclude that humidity levels in the Statehouse are indeed on the rise permanently, Schutz said he and his department have started to discuss potential solutions should there be a need to lower the humidity in summer.
Rea said his department is looking at options for heating the Statehouse, but the issue is where to locate a boiler, where to put the extensive duct work that would be necessary while maintaining the historic setting of the building.
Then there is the question of providing air conditioning to take moisture out of the air. A temporary solution now in use is to bring in fresh air from the outside; units on the roof exchange air for this purpose.
As a short-term solution to the high humidity at the Statehouse, consumer-grade dehumidifiers have been placed in areas where humidity has spiked.
At this point, Rea said, the state has not put long-term measures into its building plan. However, he and his department are “looking at it more seriously after this year.”