Posted on February 18, 2021
ICF residential construction is more and more attractive. ICF construction is the antidote to concerns about mold, mildew, wood rot and insects. Homeowners appreciate the peace-of-mind that concrete walls deliver. Concrete resists threats posed by high winds, wildfires and earth tremors. Maintenance costs are low to non-existent. Resilience and thermal mass reduce the environmental footprint of a structure.
Framing Choices in the Residential Market
For a long time, stick framing dominated single-family construction, and it still does. However, concrete is making inroads. True, wood framing still comprises about 90 percent of the U.S. market. Concrete now has a 10 percent market share. Steel-framed construction remains at less than one percent of the total.
Recently, the National Association of Home Builders (NAHB) published an article entitled “How Many Homes are Concrete-Framed?” The association says the number of concrete-framed homes is up 258 percent in the last decade. That means concrete's market share doubled in 10 years.
Various economic trends favor ICF construction.
Rising lumber prices
In a traditional design, lumber represents about one-fifth of the cost of a home. Recent price increases reduce lumber's cost advantage by thousands of dollars.
The NAHB says lumber prices increased 170 percent from April to September 2020. Some of the sudden increase is due to tariffs imposed on Canadian lumber mills. Lumber prices impact home-building decisions. A price surge in 2018 led to reductions in average home sizes.
One ICFMA study compared two wall designs. The first was a traditional insulated wood frame cavity wall using 2x6 studs. The second was an ICF wall with a six-inch core. The ICF wall reduced energy costs by 43 percent. Net-zero structures increasingly feature ICFs coupled with onsite renewable energy sources.
Other key factors
Residential ICF construction is also for those seeking safety, comfort, longevity and sustainability.
Pennsylvania faces a dual threat: long-term climate change and short-term weather extremes. Many experts predict more dramatic swings in the future. Concrete structures withstand this heightened threat.
ICF designs better withstand everything from high winds to fires to floods. Check out this video from the Insurance Institute for Business & Home Safety. It highlights the hazards of competing construction methods. Volatile weather in Pennsylvania manifests itself in many ways. Recall the ravages of Hurricane Sandy as well as tornadic activity.
A study of 49 homes revealed just how airtight ICF structures are. Average airtightness of the residences was 1.26 ACH50. ICF structures were capable of “much greater airtightness than typical wood framed houses.” ICF separating walls improve results because of reductions in room-to-room airflow. ICFs reduce wind-induced billowing more common in traditional wood-frame construction.
Today, net carbon calculations are more sophisticated. Researchers realize the importance of the entire life cycle. Carbon-intensive cement production is offset by long lifespans and minimal maintenance costs.
Researchers at MIT’s Concrete Sustainability Hub (CSHub) conducted a complete Life-Cycle Assessment (LCA). They looked at hypothetical homes in Chicago and Phoenix, representing two different climates. The LCA accounts for all phases of a building's life cycle. It begins with acquisition of materials. It concludes with demolition and recycling. MIT researchers base their calculations on a modest 60-year life cycle.
The CSHub team also developed the Building Attribute to Impact Algorithm (BAIA). It identifies the most significant environmental and economic impacts during a building’s life. The algorithm allows designers to optimize designs to reduce costs and environmental impact.
The Portland Cement Association (PCA) graphs the emissions of an ICF vs. wood-frame home. During its 100-year service life, an ICF structure saves about 110 tons of CO2 emissions compared to the wood-frame alternative. This means the ICF home will reduce carbon emissions more than the emissions generated producing the cement in the first place.
Three case studies illustrate the benefits of ICF residential construction. Homeowners enjoy energy savings, indoor comfort, sound attenuation and more.
Ohio’s first zero-energy-ready home
Charis Homes enjoys the distinction of building the first zero-energy-ready home in Ohio. The builder uses ICFs for everything from the foundation to the roof. The continuous, seamless envelope maximizes comfort and energy savings. Upon the completion of the home, blower tests confirmed airtightness. Its HERS rating is 31. Electricity and heating costs are less than $100 per month. The owners also comment on how quiet it is living in an ICF home. A geothermal system complements the energy-saving ICFs.
Award-winning home in upstate New York
In the winter, arctic air often invades the Finger Lakes region of upstate New York. A new 2,800 sq-ft ICF home handles these incursions with ease. It is the recipient of a 2020 ICF Builder Award in the “Small Residential” category. ICF walls help deliver electric bills of less than $100 per month. Two by 12 roof rafters filled with spray foam insulation provide R-60 protection. The home also features ICF decking and field-cut ICF gables.
ICF bastion at Breezy Point
Superstorm Sandy’s awful legacy included the destruction of 650,000 homes. Hard-hit was Breezy Point. This is a neighborhood sitting on a peninsula jutting into New York’s harbor. One Breezy Point homeowner enjoys the many advantages of an ICF pilot project. Peace-of-mind for one. Another is insurance savings. There's an estimated 87-percent reduction in the flood risk insurance premium. This will save an estimated $88,000 over 20 years.
The Greek philosopher Heraclitus observed that “change is the only constant in life.” Change remains the only constant in today’s concrete industry as well. For those in the industry, endless innovation delivers an exciting ride. Better, yet, it gives us a better world in which to live. Truly sustainable products endure weather extremes. Resilience is the new green.
SpecifyConcrete.org is a website of the Pennsylvania Aggregates and Concrete Association (PACA). Feel free to contact us for more information about ICF homes and other structures.