April 18, 2011
Nation's Building News

The Official Online Newspaper of NAHB

Building Systems
Young Chicago Family Builds Sustainable Dream Home Using Insulating Concrete Forms
An energy-efficient, sustainable home using insulating concrete forms was built for a young family in Chicago.

A new home built using insulating concrete forms (ICFs) ended up being the perfect choice for a young family looking for plenty of space in a neighborhood close to downtown Chicago so they could spend less time commuting and more time with their two children.

They turned to Chicago builders Leitim and Mani and architects Wrap Architecture to make their dream home possible. 

Because they planned to live there at least 15 years, the couple wanted their home to be energy-efficient and sustainable.

To achieve the couple's goals, the builder made construction elements such as the exterior envelope the top priority and budget consideration. Interior features — kitchen cabinets, floor finishes and countertops — were designed to be upgraded later as the couple’s budget permitted.

ICFs were chosen for the home because their thick, continuous thermal insulation and solid concrete reduce air infiltration more than conventional construction. High-performance windows were also added to complete the envelope and maintain good energy efficiency. Additionally, the structural strength of concrete would keep their family safer.

Project architects designed the 4,100-square-foot, four-story home — which took 10 months to complete. The exterior walls of each floor were stacked and placed within one-and-a-half weeks by the general contractor, Cian O’Mahoney, who, until this project, had never used ICFs when building a home. The ICF manufacturer provided onsite training to help speed up the construction process.

Other green and sustainable features in the home included:

  • Insulated basement floors with radiant heat, finished by staining and sealing. These decorative concrete floors can provide years of durability and eliminate carpet replacement and landfill.

  • A geothermal heating system using nine wells, each running vertically to a depth of 90 feet.

  • A solar-heated domestic water system to supplement the geothermal system.

  • A green roof made of plants in removable trays. The green roof qualified for a $5,000 grant from the city.

  • An exterior finished with fiber cement wall panels. This prefinished rain screen assembly reduces exterior painting and maintenance requirements.

  • Low-VOC paints

The stairway, open to all floors, is located along one side of the house, leads from the basement to the roof and is capped with a small penthouse structure with an operable window. The multi-story space functions like a chimney — creating a stack effect to draw air up and through the entire home.

The owners anticipate that they won’t need to use their air conditioning too much during the summer because they built the home using a combination of the well-insulated ICF walls and the natural ventilation provided by the stairway.

Although the design made energy sense, the owners wanted something tangible to prove it. So, to quantify performance, they hired a home energy rater who reviewed the plans, conducted field inspections during construction and tested and rated the home.

The house achieved a HERS energy rating of 41, which means it will perform 59% better than new homes built to minimum requirements in the prevailing energy code. That represents exceptional efficiency, particularly in a colder climate like Chicago's.

With the home complete and the family moved in, the couple has decided that the improvements they made were worth the extra money they spent.

For more information on the value and benefits of various concrete home building technologies, visit the web pages of the NAHB Concrete Home Building Coalition


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