Construction Spotlight: Insulating Concrete Forms

Posted by on Feb 12, 2016 in Housing | No Comments

For the past six years, I’ve been honored with the opportunity to chair the American Concrete Institute‘s (ACI) 560 Committee. The goal of the committee is to write ACI’s first report specifically focused on design and construction with insulating concrete forms (ICF). Prior to chairing this committee, I served as a voting member starting in 2005 and then served as secretary and vice chair prior to becoming chair. My original involvement stemmed from Schaefer’s work with an ICF form manufacturer as well as the increased use of ICF’s in residential and commercial construction led to our efforts to be more involved with ICF. Although there are a number of resources available for using ICF, the information is very dispersed and fragmented across a number of different sources with no definitive ACI guidance available. Many in the industry saw this need, and the committee was formed in 2004. The market turmoil during the great recession and subsequent industry consolidation provided an impediment to getting the committee’s work completed, but ACI has finally released the report.

While versions of ICF have been used since World War II, only two significant industry associations have released documents associated with the material. In 2007 the Portland Cement Association (PCA) released a consensus standard related to the use of ICF in residential construction (PCA-100-2007), and then in 2008, the American Society for Testing and Materials (ASTM) released a consensus product standard for ICF. These standards have been revised and help designers use and specify ICF. In the spring of 2016, it is anticipated that American Concrete Institute’s 560 Committee will release the first comprehensive ACI document specifically addressing design and construction with ICF. Since its formation in 2004, the committee has held many information sessions at different conventions and continued the hard work of developing a document that can be used as reference by builders, designers, etc. The publication of this document will further legitimize the use of ICF in the industry.

The publication of this document will further legitimize the use of ICF in the industry.

What is ICF?

ICF is a type of permanent concrete formwork that creates the external wall envelope of a building. Typically, it is standard reinforced concrete sandwiched between two faces of low absorptive, foam plastic insulating material.

Different types of ICF create concrete cores of varying size and shapes, and have different benefits, but all ICF blocks result in a reinforced concrete core sandwiched between insulating material. The bread of the ICF sandwich, the foam face shells, are typically 2 to 2.5 in thick. Typically, plastic cross ties maintain the space between the face shells, holding the shape of the block.

ICF Benefits

The benefits are quickly summarized below.

• Ease and Speed of Construction. The foam shells are lightweight and quickly assembled. A concrete construction crew can quickly place the concrete into the forms using traditional methods.
• Winter Construction. ICF can be safely constructed at temperatures lower than walls cast in reusable forms (unless those walls are draped with insulating blankets or “heated” in some manner).
• Strong Thermal Performance. The final wall system is already insulated and provides good overall thermal performance.
• Disaster Resistant. Concrete is inherently resistant to tornados, hurricanes, fire, rot and rusting.
• Acoustic Attenuation. In occupancy surveys, the number one response about the quality of living was the lack of noise in the new home. The sound-blocking nature of ICF is ideal for urban sites where nearby road/highway noise is a major complaint. It’s proven by the sound transmission coefficient (STC) ratings – where ICF’s pegged STC values near 50.
• Cost. ICF can be nearly the same cost of other building materials, depending on the contractor’s familiarity with the product.
• Usage. As with all materials, they are better suited for some projects than others; the key is for your design team to understand when to use them.

ICF Awards

Annually, ICF Builder holds a project-based competition for the best use of ICF. This year, three projects where Schaefer provided structural design were chosen as winners in their respective categories.

Holiday Inn (MultiFamily Division) | 1st Place Winner

This hotel in Northern Cincinnati has the traditional hotel amenities including 130 guestrooms, an indoor pool, and a fitness center, as well as a chapel and ballroom that can accommodate 650 people for weddings and other formal events, and even an upscale restaurant and bar area. Foxblocks ICF forms were chosen for this project for the thermal values, speed of construction and to lessen sound transmission between rooms. Kyle Kusmer and Bill Moster carried the structural design effort for this project.

Christian Life Center (Light Commercial Division) | 2nd Place Winner

As part of a renovation and 40,000 sq ft expansion of the Christian Life Center near Dayton, Ohio, the existing sanctuary structure was demolished and replaced with a new auditorium-style sanctuary for 2,100 people along with an expanded atrium space, reception room, classrooms and offices. The new auditorium structure consists of metal deck on roof joists and joist girders supported by steel columns and load bearing ICF walls. The lateral force resisting system for the structure consists primarily of ICF shear walls along with steel moment frames.

The developer chose ICF forms for wall construction on this project. Having used ICF on a number of projects, the developer determined ICF to be an efficient method of construction. The ICF forms also allowed the team to easily lay out and form the radiused exterior walls around the perimeter of the addition. Kyle Kusmer, Joe Seymour and Susan Roosen led Schaefer’s effort on this project.

Indian Hill Estate Home (Unlimited Residential Division) | 2nd Place Winner

This large single-family residence used ICF because the family wanted a durable, substantial and quiet residence. The team used an insulated floor forming system for the exterior decks and integrated those with steel beams for supports. Since the construction, the family has been very pleased with the Old World-feel the thick walls provide. The family has chosen to keep the specifics of its home private. Jim Graham, Matt Horne and Robert Rogers collaborated for the structural design on this project.

On behalf of the entire design and construction team, it is always an honor to be recognized for the good work we do every day. Schaefer strives to be a good steward, and to be part of our industry’s future by finding more efficient products and processes for design.

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