Washington Monument Restoration
by Joel Davis
Photos Courtesy Lorton Stone, LLC
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Careful stabilization and restoration of the Washington Monument’s top (pyramidion) was needed after a 5.8 magnitude earthquake damaged the structure in 2011. The experts from Lorton Stone, LLC relied on Last Patch Gel epoxy and cartridge system Crack Repair injectable epoxies formulated by Bonstone Materials Corporation to repair or replace the damaged stone. |
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Lorton Stone, LLC used Last Patch as a surface seal for cracks on the pyramidion stone panels. “We chose to use it because Last Patch can be color matched and is UV stable,” Flynn said. “We also used Past Patch to patch chips and anchor holes. Bonstone did a great job color matching the epoxy. They gave us a range of colors to choose from.” |
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Above: Repairing a sizeable chip in the monument’s pyramidion. Safety screen on the scaffolding can be seen in the background. |
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Above: Bonstone provided color matches to suit the color variations found on each side of the monument, due to 127 years of weathering. |
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Above: Extensive spalling and cracking damage on a corner section, at the edge of the pyramidion. “Last Patch Gel material is a UV stable patching system for honed finishes and sandblasted and chiseled stone. You can get that honed look with it.” |
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Above: Bonstone Crack Repair 28 is a medium viscosity epoxy delivered by injection with a cartridge system into thin cracks in stone. |
Struck by natural disaster in 2011, the Washington Monument in Washington, D.C., stands proudly refurbished and open today. The craftsmanship of Lorton Stone, LLC and the formulating expertise of Bonstone Materials Corporation were both vital to the effort.
The 555-foot obelisk honoring America’s first president reopened to the public in May 2014. It had been closed since Aug. 23, 2011. That was when a 5.8 magnitude earthquake struck. It caused significant damage to the structure.
The heaviest damage was to the pointy top of the Washington Monument. Called the pyramidion, it is between elevations 475 feet and 530 feet, according to the National Park Service. Damage included cracks of up to one inch wide in some of the marble blocks. Other damage included spalling of the stones and missing mortar.
Crews from Springfield, Va.-based Lorton Stone, LLC performed all of the stone restoration work on the monument. This included Dutchman patches, repointed mortar joints, and injecting grout into displaced joints. The company also injected epoxy into cracked stone panels and installed structural steel. It eased stone edges, repaired cracks, reattached stone spalls, and installed joint sealant.
According to ENR Mid-Atlantic, about 90 percent of the work was performed on scaffolding at exposed elevations of up to 555 feet. “It was extremely challenging,” Project Manager Shane Flynn of Lorton Stone, LLC said. “From the moment work began, all eyes were on us. We were also hanging off the Washington Monument on swing stages, so there were a lot of safety concerns.”
Every morning, the company’s foreman would inspect all the rigging and lifelines. He would go through an extensive safety checklist. Every day there were safety talks with the crew. Every week there was a review of site-specific safety hazards. “Victor Castro, our foreman, deserves special mention,” Flynn said. “He was on-site every day and managed all of the workers. He made sure everyone worked safe and work was complete to owner’s satisfaction.”
Castro’s diligence paid off. There were no recordable safety problems for Lorton Stone, LLC employees during the project. Castro is a 2009 inductee of the Washington Building Congress Hall of Fame. He has more than 30 years of experience in the field.
“We value safety,” Flynn said. “Our clients know this. Our employees know this. We employ a third party company to conduct monthly safety inspections on our job sites to ensure we have the best and safest possible environment for our employees so they can concentrate on producing the best product for our client.”
Bonstone Materials Corporation provided stone adhesive products to Lorton Stone, LLC for the repairs. “It’s a prestigious project,” said Paul Klees of Wisconsin-based Bonstone “You want to get the best material up there to hold it and make it last. There is a lot of care-taking with working with the contractor and the specifiers on it.”
“It was a once in a lifetime experience,” Flynn said. “I got to touch the top of the monument. Not many people get to do that. The view from there was incredible. It’s priceless. It is hard work, though, but definitely memorable. The historical significance of these landmarks and the importance in people’s hearts and minds is not lost on us.”
Bonstone has been manufacturing adhesives for the stone industry for five decades. It also manufactures patching products. “We’ve worked with this contractor for years on government projects in the D.C. area,” Klees said. “They’ve used our products for the last 25 years. They are used to the durability of Bonstone products.”
Numerous “Dutchman” repairs — more than 150 — were made and cracks filled at the top of the structure, where most of the damage occurred. “(A Dutchman patch) is where they have a piece that they don’t want to repair,” Klees said. “They want to square it up and cut it out and put a whole new piece of stone in there. They use our product to put it back in place.”
A Dutchman patch can range in size from four inches to a foot-and-a-half. “In most cases when they are doing Dutchmans and reattachment, they are going to use a (physical) anchor for the safety factor.”
The majority of the restoration was the actual labor for cutting out Dutchmans, Klees said. “Our products were used to glue the Dutchmans back in. They are all designed to create a bond that is able to support a stone body, and typically you expect the stone to fail before the epoxy.”
In addition, Bonstone provided its expertise in matching colors. “We provided five color matches for the capping material,” Klees said. “The material that is used for patching the cracks before it’s in injected. If you inject it without having capping material, it’s going to run right out of the hole.”
Using adhesive to fill cracks requires an extra step. “The pressure from pushing it in and the viscosity of the resin will force it out of the hole. You have to have something in there. You have to cap the crack so it won’t let it back out.”
After 127 years of weathering, occasional cleanings, and changing atmospheric conditions, the color of the monument’s stone is not consistent, he said. “The south side of the monument is going to be a different shade than the north side, versus the east and west, plus dirt and the previous cleanings will create variations in the marble so you have to compensate for that.”
“We provided color matches of different variations of the stone just from weathering,” he said. “That was also used for small chip repairs as well”
Lorton Stone, LLC has restored many of the most notable landmarks in the capital: the National Cathedral, District of Columbia War Memorial, the U.S Supreme Court, and the U.S. Capitol. “Lorton Stone has been doing stone restoration in the D.C. area for a long time,” Flynn said. “We provide full service from quarry to project. Our experienced workforce, expertise and facilities provide clients with complete services in budgeting, in-house drafting, purchasing, and installation. “
Lorton has an approximately 7,000 square foot fabrication facility. It is equipped to perform any type of cut-to-size stone work from simple paving project to a book-matched, reversed knife-edge conference room table, Flynn said.
“Our clients can come visit our showroom displaying the latest available types of stone. We have over 20 acres of storage facilities within 30 minutes of downtown Washington, D.C. Very few, if any, competitors can claim the same ability to provide, in-house, such a complete package. That’s just on the facilities side. More importantly, we are extremely proud to employ supervisory personnel with combined experience of well over 100 years in performing all types of stonework, in addition to the experience of stone setting mechanics and their helpers.”
Crews and employee totals can fluctuate depending on Lorton’s needs; however, its workforce generally consists of 100-110 full-time field employees.
Bonstone offers natural stone restoration products. The applications include structural bonding, anchoring, crack repair and patching systems. The company manufactures state of the art UV stable patching products. They are used for limestone, sandstone, granite, and marble. They are also used for other natural stones. Custom color matching is also available.
The Bonstone products used in the Washington Monument repair include:
Last Patch Gel
“An exterior grade, UV stable stone repair compound for granite, marble, travertine and other honed to polish limestone surfaces,” according to Bonstone marketing materials. “This resistance to sunlight sets Last Patch Gel apart from nearly all other products in the market.”
“The Last Patch material is a UV stable patching system for honed finishes and sandblasted and chiseled stone,” Klees said. “You can get that honed look with it. “It’s not going to discolor in ultraviolet. We pre-color it so it won’t stain the stone.”
Lorton Stone, LLC used Last Patch as a surface seal for cracks on the pyramidion stone panels. “We chose to use it because Last Patch can be color matched and is UV stable,” Flynn said. “We also used Past Patch to patch chips and anchor holes. The product worked well and the guys in the field had no complaints. Bonstone did a great job color matching the epoxy. They gave us a range of colors to choose from.”
Last Patch can be used for aesthetic patches and repairs on fine grained stones. It is also useful for building facade repairs, chips, spalls and sign hold repairs.
Crack Repair 28
Crack Repair 31
Other repair projects that Bonstone has been involved with include:
- The Getty Center in Los Angeles, CA
- The White House
- The U.S. Capitol Building
- Longfellow Bridge in Boston, MA
- The Minnesota State Capitol
- The Kansas State Capitol
- See the Bonstone project portfolio here
For more information on Lorton Stone, LLC visit their website www.lortonstone.com.
For more information about Bonstone Materials Corporation, visit: www.bonstone.com
For more information or to order the Bonstone products mentioned in this article visit www.braxton-bragg.com.