Trinity Cathedral, Pittsburgh

October 11, 2007

That’s certainly the case at Trinity Cathedral, where removing almost 140 years of industrial grime is leaving parishioners with a surprise: their church isn’t black.
Revealing the pinks and yellows of the church’s Pennsylvania sandstone is only one part of a $2 million project that also includes a re-landscaping of the downtown property, complete with restoration of the memorial markers in the adjoining historic cemetery.
The Rev. Canon Catherine Brall, provost of Trinity Cathedral, says the idea of cleaning the structure isn’t a new one. Her predecessor as dean of the cathedral began investigating cleaning options in the early 2000s.
“He even tried to get some estimates for the cleaning, but there weren’t funds available at that time, and then he ended up leaving this church,” she explains.
However, as part of his research, the locally-based Atlantic Engineering Services (AES) –located only blocks from the cathedral – came into the project.
Gilbert Kaufman, AES’s president, says he’s not even sure how his company became involved, but he suspects it might have been suggested to the previous dean by the staff of a nearby church where AES supervised the cleaning.
Kaufman adds that, over the years, specialty restoration of stone structures has become an AES niche – and quite a successful one.
“It started with a similar project where a stone steeple was in very bad shape,” he explains. “We had been called in as the structural engineer. When it came time to determine how to clean the building, the architect backed away.
“Because it was a structural thing, we got involved in it, and over the last 20 years we’ve done a series of projects, many of them churches.”
When the decision was made to finally go ahead with this project, Brall says it was natural to go back to AES.
What spurred the Episcopal Diocese of Pittsburgh and the congregation to fund the work is the anniversaries of two significant events that will be observed next year.
“Pittsburgh is having its 250th anniversary,” Brall explains. “In addition, at Thanksgiving 2008, our Episcopal diocese will observe the 250th anniversary of the first Protestant worship service held in Pittsburgh, which happened to be an Anglican service. We wanted to celebrate in a big way.”
She adds that the downtown location of the church has made it a Pittsburgh landmark and a building utilized by people of all Christian faiths.
“We really wanted to honor our church, and it’s a beautiful, beautiful building,” she says.
The restoration of the adjoining historic burial ground and landscape work to the property, including grading and the installation of new bluestone walkways, was precipitated by a separate bequest.
Brall explains that twice previously, the congregation has availed itself of the services of the University of Pennsylvania’s Architectural Conservation Laboratory to help maintain the remaining portion of what is the oldest burial ground in Pittsburgh.
“The work started in 1990, and part of it was done then,” the canon says. “Later, more funds were available and another phase of the work was done. This bequest should allow us to finish the work completely, restoring and preserving the burial grounds and stones as much as possible.”
The additional landscape work, including grading, was designed to create a more-inviting setting, improve drainage away from the building, and also remove a layer of soot 4”-12” deep that settled on the site.

BEST WITH BAKING SODA
AES took what Kaufman describes as a multi-faceted approach to evaluating cleaning methods for the cathedral before settling on a baking-soda method the company has recommended for some other projects it has done.
“The city looks on it very benevolently because it’s environmentally a very natural kind of process,” says Kaufman. “There aren’t any chemicals involved, there’s no overspray, and it’s not particularly harmful to people or landscape.”
Still, he adds that the company has had enough experience with tough cleaning jobs that it seemed prudent to look at other processes, including the use of chemicals. The church’s building committee also had some suggestions, and ultimately a handful of firms were brought in to do test sections.
“We gave them a test area and said, ‘Here’s 100+ years of Pittsburgh soot and grime; go at it,’” Kaufman says. “That allowed us to see what would work best. The baking soda was also the fastest method, so the testing allowed us to pinpoint it as the right method to use here.”
While this process was being completed, church officials also opted to bring in a local construction company to act as its representative for the project. Canon Brall explains that LLI/CMI Construction of Wexford, Pa., was hired for that job because one of its principals is a parishioner.
“The church was trying to manage the job itself, but it just became too big for them to manage,” says Eric Pomaybo, who’s handling the project for LLI/CMI. “They hired us for construction-management services, and while we’re a general contractor, we’ve done several large church projects.”
Once AES specified baking soda as the cleaning method for the job, the firm reviewed the bids of the cleaning contractors, aided by LLI/CMI. The successful contractor: Carnegie, Pa.-based Young Restoration Co. Inc.
“Young has a history of using this application and a good track record,” says Pomaybo. “Performance has shown what their abilities are.”
Steve Young, Young Restoration’s owner, says he was invited to bid by AES because of the firm’s experience using the baking-soda method. The company, which has been in business for 24 years, was an early adapter of the process, developed by the manufacturers of ARM & HAMMER® Baking Soda in the late 1980s.
Young agrees with Kaufman that the method is environmentally friendly, and he adds that it’s become a popular choice in historic situations. The method is quite similar to sandblasting, although Young uses the term “micro-blasting.”
“We take baking soda and other powders, put them in a pot with a top on it and then pressurize it,” he explains. “We use a variety of nozzles and tips, but the soda medium is shot out of the pot at very low pressure but very high volume. It takes the carbon off, but shatters before it starts to hurt the stone.”
To keep the dust down, a water curtain is shot from a separate hose above the soda.
“It’s not creating any problems for the people underneath,” says Young. “And, the landscape people are working there, and the people taking care of the headstones and the people going to church.”

BROAD SCOPE
That’s not to say everything has been smooth sailing since work began in early June. Besides cleaning, the scope of the project includes stone repair, custom stone patching and re-pointing of joints.
Because the cathedral was finished in 1871, there’s been a fair amount of stone repair involved, especially around four pinnacles that support limestone clocks.
“We’re redoing the pinnacles at the base where the clocks are,” says Young. “We’re taking stone off, rebuilding where necessary, and putting new pins in. When they built this, all the decorative stone was set with carbon-steel pins. In 140 years, those pins have rusted and created problems; we take them out, put in new stainless-steel pins, redo the stone, and then reinstall it.”
Those spires have also created a problem with the cleaning, which Young says may be the toughest part of the work. At some 60’ higher in elevation than the test sections, the carbon deposits on the spires proved to be almost as hard as steel.
“We had to have it chemically analyzed, and then we’ve used a couple different processes to break it down to where we could get it off,” he says. “You aren’t going to do a test sample 150’ in the air, but we’re speculating that because it was so much higher than the rest of the church it wasn’t protected by the buildings around it.”
AES was called in to help assess the situation with the spires, and Kaufman says the decision was made to go with a detergent overlay on those sections.
“By putting the detergent on ahead of time it helps break up part of the crust,” he says. “We’ve had a lot of success with that.”
For a 140-year-old-plus structure, Young says there hasn’t been a lot of stone that’s needed to be replaced, although his company is doing some of that.
“We had a little trouble matching the sandstone initially, but it’s a fairly common stone here in western Pennsylvania,” he says. “We have a supplier about 60 miles north of here who’s found us a really good match, and we’re custom-cutting or carving it as we need.”
To finish off his part of the job – which Young estimates will total 40,000²-50,000 ft² when completed – the company is treating some areas with a stone product from PROSOCO Inc. to help stop further deterioration.
Along with the spires, Young says the other challenge to the job is simply sharing the small city space with the landscape and architectural conservation teams.
“It’s a very small space and we’re working together quite nicely,” he says.
The church’s Brall says there’s no parking at the site, no street space, and it’s been very difficult at times to get permits from the city. Still, she agrees the three groups have kept things positive.
“From the first, everyone that’s worked on it has been tremendously dedicated and bent over backward to support each other,” she says. “They’ve been very good.”
Brall admits that the building restoration work, which is scheduled to be wrapped up this month, put a strain on parish members.
“Obviously, Young is using water from the parish, the entrances are restricted at some times, and at some times they’re blocked, so it’s been an issue,” she says.
There’s also some concern about the church’s image.
“Most people believed it was made of black stone, and some have very strong feelings about the black building,” says Brall. “The black stones, for many folks, honored Pittsburgh’s smoky history, although there’s a lot of pride in how beautiful the building is now that it’s clean.”
Her hope is to develop an exhibit in one of the hallways leading to the burial ground showing chips of the black stone, as well as explaining the cleaning process and why it was done.
Ultimately, Brall calls the job, “a crazy challenge,” and the companies involved in the job agree it’s been quite a job on which to be involved.
“It’s been a very satisfying job for the people working on it,” concludes Young. “They take a lot of pride in the fact that our company is doing the job, they’re doing a very good job and they’re really proud of it.”