Earning LEED Certification on Retrofit Projects

In the United States, about half of America’s commercial buildings were constructed prior to 1980, before climate change, global warming and sustainability became everyday phrases. In the US alone, those older buildings consume 41% of the nation’s total energy use, through lighting, heating, air conditioning, elevators and the thousands of items plugged into their sockets. 

With new construction stalling, it makes sense then that the trend in building construction is shifting from new construction to retrofits. In fact, McGraw Hill estimates that 61% of all construction projects today are retrofits. Therefore, contractors are presented with huge opportunities as building owners seek to curb energy usage through retrofits of their existing buildings.

Retrofit Ready

The US federal government, with thousands of facilities and vehicles in locations across the country and abroad, is one of the largest energy consumers in the world. However, energy consumed by federal government facilities has generally been declining over the past four decades, mostly due to efforts of the United States Green Building Council (USGBC) and their Leadership in Environmental Energy & Design (LEED) program.

The federal government has consistently been implementing LEED certification standards as a result of the U.S. General Services Administration's (GSA) endorsement of LEED as its preferred green building rating system. This makes government buildings a prime candidate for retrofits to reduce their energy consumption.

Forrester Construction was asked by the Government of the United Arab Emirates (UAE) to renovate, re-use, and expand a vacant century-old Ambassador’s residence on Massachusetts Avenue in Washington, D.C. The scope of work included stabilizing structural issues, repairing the historic fabric of the building exterior and renovating the building’s interior to modernize the space for offices, meetings rooms and student facilities.

“As the United Arab Emirates diplomatic mission in the United States has grown in recent years, the embassy required additional space to increase the facility’s overall capacity,” says Kara Borton of Forrester Construction, the general contractor on the project. “The historic ambassador’s residence structure also required preservation and modernization work after being largely untouched for many years.”

Going Green

With a new building, engineers and project owners can design the project from the ground up to obtain specific credentials, but retrofits but obviously retrofits add additional challenges.

The project team employed a number of strategies on this retrofit project to achieve LEED certification. Forrester installed new energy efficient mechanical, electrical and plumbing systems, developed a plan that recycled and diverted over 80% of construction waste and sourced regional, recyclable materials where possible.

The building’s new structural system reused over 50% of the existing structures wood joists and over 70% of its masonry bricks to rebuild the chimneys. Since this project was a historical renovation, Borton says it was also important to find ways to improve the efficiency of features to be preserved.

For example, the building’s original windows had to be redesigned to meet the LEED testing requirements. To do so, the project team researched the window’s features and found ways to enhance performance by increasing the glass’ energy efficiency while conforming to the historic design requirements. After many rounds of testing and design variations, the final version was able to achieve both aims.

“Existing conditions can only be truly verified once construction is underway, so it is more challenging to meet LEED criteria on a retrofit project,” Borton says. “There may be items that are difficult to accommodate or special materials that do not meet original LEED goals.”

“For example on this project, the original historic structure had wood columns supporting the portico that needed to be replaced. At the outset, the team thought finding replacements would not be a challenge, but it turned out the ornate column capitals were no longer manufactured and had to be replaced with custom fiberglass pieces. Since this would no longer count towards the Materials and Resources Credit 7, FSC Wood as planned, the project team was able to substitute FSC beams used elsewhere to make up for the loss. This illustrates that the true challenge of retrofitting while achieving LEED certification is to look for opportunities to exceed goals to allow for unexpected changes encountered in the field.”

The retrofit project began in September of 2013 and finished in February.

The USGBC granted the UAE Embassy LEED Gold status for its strategies for improving their building’s environmental and human health performance according to a range of criteria. These include energy efficiency, water usage, waste management, materials selected, transportation and indoor environmental quality.

“By embracing sustainable solutions, the United Arab Emirates Embassy was able to create a comfortable, healthy environment for their growing staff while lowering energy consumption,” Borton says. “The United Arab Emirates Chancery has the distinction of being one of the first embassies to be LEED certified. This encourages others in the well-known Embassy Row to think “green” and embrace environmentally friendly strategies while improve their workplace environments.”