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    HomeWhat We DoMajor ProjectsCannon Renewal
Cannon Renewal Project Overview
The Cannon House Office Building, the oldest Congressional office building outside of the Capitol Building, is in need of a complete renewal.
        
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Need for Renewal

The century-old building is plagued with serious safety, health, environmental and operational issues that are rapidly worsening. Without action, the essential systems housed behind the walls and in mechanical rooms will continue to crumble and fail, impacting members, staff and constituents.

The Cannon Building has not received a comprehensive systems upgrade since the 1930s, and many of the building's systems are original – dating back to 1908 or earlier. The systems are past the end of their useful lives and the increasing risk of their failure jeopardizes the building's long-term functionality and safety. Other necessary work includes upgrading infrastructure systems and repairing the exterior stone façade.

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    Cannon Building by the NumbersThe Renewal Process

The Cannon Renewal Project will provide an effective workplace for the next century to serve the needs of the U.S. House of Representatives and support Congressional operations.

The renewal process is scheduled to take approximately 10 years, with each of the five phases (0-4) aligned to fall between Congressional move cycles. Phases 1-4 of the project will require that affected wings of the building be vacated. Members and their staffs will remain in the upper campus, while some Committee and support staff will relocate to the Ford House Office Building or the O'Neill House Office Building.

Modernizing the Cannon House Office BuildingPhase 0 began after the 2014 election and had a low impact on building occupants. This phase included installing building utilities, primarily in the basement and the moat area of the courtyard. This enables future work to connect to the new systems, minimizing shutdowns and disturbances.

Phases 1-4 impact a quarter of the building, one side at a time, starting with the west wing in 2017 (New Jersey Avenue) followed by the north wing, east wing and concluding with the south wing. Construction work occurs around the clock, with activities ongoing throughout the day and night. The noisiest work takes place during the night and early morning.

Project Updates
	Project Frequently Asked QuestionsConstructing a New Fifth Floor

When the Cannon Building was first occupied in 1908, there were a total of 397 offices – one for each representative – and 14 committee rooms. By 1913, the House had outgrown the office space in the building. An additional 51 rooms were added to the original structure by raising the roof and constructing a fifth floor, which was originally designated as storage space.

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    Rendering of the completed Cannon House Office Building fifth floor.

Rendering of the completed Cannon House Office Building fifth floor.As part of the Cannon Renewal Project, a completely new fifth floor will be constructed during each successive phase. Member offices will flank both sides of the corridor, as they do on the lower floors. Work includes demolishing the walls and roof, then rebuilding an entirely new fifth floor.

Historic Preservation

In December 2020, members of the House of Representatives and their staffs moved into office suites that were renovated during Phase 2 of the Architect of the Capitol's (AOC) 10-year Cannon Renewal Project. This marked an important milestone of Phase 2, which focused on restoring the north wing of the Cannon Building that runs along Independence Ave., SE.

Although the interior of the north wing underwent an extensive renovation, the historic exterior of the 112-year-old Cannon Building received a partial facelift. All of the original windows were restored, all exterior stonework was cleaned, and joints were pointed and sealed to make everything water tight.

Some exterior stone was replaced including modillions, window cornices and stonework fronting the renovated ground-floor level that contains new member office suites. "The north elevation of Cannon was originally built with marble quarried in Dover, New York," said AOC's Historic Preservation Officer Mary Oehrlein. "Because that quarry has since closed, the best match we could find for the original stone was Vermont marble."

Historic Preservation: Cannon House Office Building (Video)
	Cannon Light Fixture Restoration (Article)
	Preserving Historic Windows and Doors (Article)
	Cool Cannon Construction Finds (Article)
	Revealing a Tiled Treasure (Article)
	The Cannon Building's Refreshed Rotunda (Article)Balancing Safety and Preservation

The dominant architectural feature of Cannon's north façade is a grand colonnade spanning the third and fourth floors above Independence Avenue. The colonnade is composed of 34 fluted columns styled in a modified version of the Doric order. The columns were cleaned as well as meticulously analyzed and repaired to ensure long-lasting stability and safety. "Although safety is always a top priority," said Cannon Renewal Project Executive Donna Klee, "the AOC also follows a preservation methodology that seeks to keep as much historic material as possible in place. We'll remove anything that isn’t safe, but we're also not trying to make the building look new."

In some cases, that meant removing loose bits of stone from the columns that could not be securely pinned in place. The small nicks and gaps left behind reflect a treatment where less is often more and any repair work done is seamless or not done at all. "The columns are still beautiful," said Klee, "and they reflect a balance between safety and preservation that we needed to strike for this particular project."
          
    
    
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