ICF Curved Walls: How, When, Where and Why

Posted on March 04, 2021

When you think of a wall built from insulated concrete forms (ICFs), you may picture a linear design. This is understandable. The majority of ICF walls are just that. The idea of a curved ICF design may seem a bit counter-intuitive, at least at first. However, ICF radius forms are readily available. Some contractors fashion curved walls from straight ICF forms as well.

Decorative Concrete Pool

Radius Walls Mean Greater Use of ICFs

ICF radius walls are increasingly common in both residential and commercial construction. Expanding use of curved ICFs will further expand the ICF market.

Curved ICF walls give architects and designers tremendous design freedom. It’s possible to devote oneself to aesthetics without making sacrifices elsewhere. ICF radius construction delivers the same safety, durability and energy savings that linear ICF walls do. ICF walls protect against high winds, wildfires and earth tremors. They are a key component in the quest for net-zero energy performance.

Radius blocks deliver the advantages of EPS foam to curved wall designs. The closed-cell foam has a high R-value per inch, generally about R4. It is a stable, durable foam with no off-gassing. It is very resistant to moisture, mold and rot. The material contains a flame retardant, and the smoke is non-toxic. EPS foam is recyclable.

Curved Walls: Construction Options

Major manufacturers offer ICF radius forms from tighter to more gradual. Fox Blocks offers pre-formed radius blocks that are 16 inches long. They accommodate a six-inch concrete core. These special-order blocks come in a variety of arc radii, including five, six, seven, eight, nine and 10 feet. BuildBlock ICFs also offers customized radius blocks. Learn more from their BuildRadius video. LogixICF includes directions for creating radius walls in their installation guide.

For more gradual curves, it is possible to fashion radius forms from straight ones. Here’s a nine-minute how-to video.

Case Studies

Public awareness of the advantages of ICFs is still expanding. Many residential and commercial have already enjoyed them for more than a decade. Here’s a mix of earlier and more recent projects that make prominent use of curved ICF walls.

Pools and spas

In the early days curved designs were most prominent in ICF pool construction. They remain popular due to speedier construction compared to pour-in-place. Lightweight components are easy to assemble. Avoid the use of heavy construction equipment. Opt for custom designs and varied finishing options.

The continuous insulation inherent in ICF construction is also perfect for pools. Energy savings of up to 60 percent accrue. Thanks to the insulating capacity and thermal mass, ICFs better maintain water temperatures. This can even extend the pool season. Imagine the weeks and months of added fun that will accumulate in coming years. Finally, longevity and reduced maintenance costs bring peace-of-mind, year after year.

Homes with curved walls

Extreme weather resistance is a prime calling card of ICF construction. Consider the striking images of ICF homes still standing in the aftermath of major hurricane strikes. Tuscan Place is a 5,000+ sq-ft home featuring ICFs and windows rated to 160 mph. Foam sprayed on the underside of the roof decking complements the energy-efficiency of the ICF construction. Dual Trane heat pumps complete the quest for low energy costs.

A multi-story ICF home outside of Tupac, AZ, won an ICF Builder Award in the Large Residential category. The 3452 sqft home is in southern Arizona’s Santa Rita Mountains at an elevation of 4500 feet. There’s more than 6700 sqft of ICF walls, including five radius walls. These curved walls featured radii of four, five, 9.5, 20 and 45 feet. The site was 25 miles off the main highway, and the last seven miles was dirt, so ship-flat ICFs were an advantage. The final leg of the journey was quarter-mile-long drive with a 200-ft elevation change.

An inventor’s ICF home in Leverett, MA, includes many curved walls fashioned from linear ICF blocks. The net-zero, multi-story residence incorporates passive solar and partially earth-faced north-side walls. Thanks to ICF construction, there’s “lots of mass for thermal heating and cooling.” The ICF Builder Award winner also benefits from solar and geothermal energy systems. The homeowner said of his decision to use ICFs, “I can say with 100% confidence that it was the right choice for our dream home. After 30 years in home construction, I will never go back to conventional built.”

Curved retaining walls

ICF construction is very straightforward. So much so that some contractors choose it when R values are not even a concern. Energy savings is not a consideration with retaining walls. ICF retaining walls do deliver labor-saving installation and structural integrity. ICF radius blocks offer quick and precise retaining wall installation.

Design Freedom in Commercial Projects

Design freedom is key in major commercial projects as well. Architects have long expressed their creativity in church design, for example. St. Mary’s Church in Carmel, IN, is a perfect example. Curved ICF walls simultaneously deliver aesthetics, durability, longevity and energy savings.

Learn More

The Pennsylvania Aggregate and Concrete Association (PACA) maintains the SpecifyConcrete.org website. For more information, or for help with an upcoming project, please contact us.