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The Portland Building, which houses more than 1,300 city employees in dozens of agencies, is one of the most iconic buildings in the City of Roses. But it also has proven to be one of the most trouble-prone.

Almost immediately after the building was completed in 1982, water began leaking into it. From 1990 to 2012, eight major efforts were launched to address structural performance issues.

鈥�(The City Council) finally decided that nickel and diming it wasn’t working,鈥� said Jen Clodius, a senior management analyst and public information officer for the Portland Office of Management and Finance. 鈥淚nstead of throwing chump change at it, last year they authorized the (full reconstruction) project.鈥�

The project has a budget of $195 million and is scheduled for completion by 2020. Fixing a myriad of structural problems will be a tall order.

Chief among the issues is the performance of the building’s envelope. The mostly reinforced concrete enclosure lacks water-shedding features included in many comparable buildings. Also, the concrete structure has no exterior cladding other than paint. The inability to shed water has caused extensive damage to both the building’s interior and exterior.

DLR Group was contracted to devise a plan to address the structure’s numerous issues.

鈥淐learly a very high priority is that the envelope perform and keep water out,鈥� said Carla Weinheimer, project manager for DLR Group. 鈥淭he initial approach was not going to allow that envelope to work.鈥�

While water leakage was the highest priority, it is not the only architectural challenge facing the project team. The fact that the building was constructed from so many different types of material also poses difficulty.

鈥淲e have stucco, tile and concrete,鈥� said Kristin Wells, project manager for the city of Portland. 鈥淭hey all move at different rates. The way they move together is a challenge. It creates a point of weakness.鈥�

Energy efficiency was a high priority when the building was built. Unfortunately, the technology of the 1970s and early 80s presented obstacles to meeting those goals.

鈥淭he black glass they used back in 1982 was a response to the energy crisis,鈥� Weinheimer said. 鈥淭he light is compromised by the glass. One thing we want to see is improved daylight.鈥�

While addressing all of those technical issues, the project team is also charged with preserving the look of one of the most iconic examples of postmodern architecture in the country.

鈥淎 big question was how do we respect and treat it in a way that enhances the technical performance and maintains the architectural concept of the building,鈥� Weinheimer said.

The solution came from evaluating methods used for other renovation projects. Owners of the Standard Oil Building in Chicago replaced all of the original marble cladding when it cracked under thermal and wind pressures. A new skin of modern curtain-wall framing and glazing was used to stop leaking at the Lever House in New York. Entirely new front glazing was used at Crown Hall at the Illinois Institute of Technology in Chicago to address damage from condensation and harsh weather.

Each of those solutions required significant changes to the buildings’ appearances. That was something the Portland design team wanted to avoid.

鈥溾�� The key thing to remember is we had to address the systems that comprised the envelope,鈥� Wells said. 鈥淭o be doing this significant a renovation on a building of this age hasn’t been done a lot.鈥�

After mulling their options, design team members settled on putting a rain screen over the existing fa莽ade. The screen will be able to shed water, relieve wind pressure and control temperature fluctuations to prevent leaks. It is also believed that the screen will stop more damage to the building’s interior.

Other advantages of the rain screen system is that there is no need to demolish existing materials and it can match the building’s exterior enclosure appearance, planar relationships and joint patterns.

鈥淭he building is significant because of what people see,鈥� Weinheimer said. 鈥淭hat is the big picture.鈥�

The rain screen will essentially create a second layer on the building’s skin. It will use multiple materials to replicate the building’s look.聽For instance, aluminum frames will replicate original frame sight lines and colors near the top of the building. Duplicate terra-cotta green tiles will mount onto concealed custom aluminum frames to duplicate existing green clay tile glazed hard surfaces at the lower three levels.

Aluminum panels with attached aluminum red tile shapes will be used to replicate the building’s iconic red ceramic tiles.聽Aluminum plate panels will also be used to match the original painted concrete聽surfaces.

鈥淲e are going to create a layer on the exterior of the building behind which there is a second layer that allows the water to drain,鈥� Weinheimer said. 鈥淭hat means that what you will see is a layer that replicates the building’s appearance and has that outer layer.鈥�

While the approach has been used in the past, it has seldom been used on buildings with historical significance comparable to the Portland Building’s. When options were considered, the choice was clear to the design team.

鈥淎s a team we had to ask ourselves what system performs and gives us the aesthetics as well,鈥� Wells said. 鈥淚t was a clear way to proceed. There aren’t a lot of other options.鈥�

The design team is looking forward to implementing its plan despite the challenges presented by refurbishing one of most architecturally significant buildings in Portland. The plan did get the seal of approval of Michael Graves Architecture & Design, the firm responsible for the building’s original design.

鈥淟ooking at it from our own standpoint, it’s an interesting design problem,鈥� Weinheimer said. 鈥淲e know this will be looked at nationally and internationally. We have been given a chance. With this new holistic approach, we will make the building useful and wonderful.鈥�