Insulating concrete forms have a long history of success in low-rise buildings, but now Building Teams are specifying ICFs for mid- and high-rise structures—more than 100 feet. ICF walls can be used for tall unsupported walls (for, say, movie theaters and big-box stores) and for multistory, load-bearing walls (for hotels, multifamily residential buildings, and student residence halls).
Our trusted ICF experts offer the following tips for designing and constructing tall ICF walls:
1. Pre-plan your job by drawing a simple cross section with the ICF you are using.
The cross section will show you how openings line up with the coursing of the ICF joints and where embeds will be placed, says Glen Klassen, regional manager with ICF manufacturer Arxx, Cobourg, Ont. "During the build process, your crew can follow this cross section to know when to stop placing forms and start placing embeds."
2. Account for the ICF formwork course height.
Designers can greatly reduce the amount of formwork cuts the contractor will be required to make by considering the course height of the ICF product when designing the walls, says Kelvin Doerr, VP of engineering and technical services for Reward Wall Systems, Omaha, Neb. Doerr says architects should factor in wall heights, window heights, and floor elevations when possible.
3. Base concrete slump and aggregate size on ICF manufacturer recommendations.
Both concrete slump and aggregate size are impacted by the formwork tie configuration within the formwork cavity, as well as by the amount of open space available around the ties to allow concrete to effectively flow within the forms, says Donn C. Thompson, AIA, LEED AP, CGP, director of Low Rise Buildings with the Portland Cement Association, Skokie, Ill. "Ties with smaller openings will require smaller aggregate to insure the concrete flows effectively through the forms," he says.
Arxx's Klassen offers this rule of thumb: If the concrete is restricted slightly at the top form around the rebar before flowing into the wall, it's just right. If the concrete gets restricted to the point of not flowing down into the wall, it's too low of a slump. If the concrete flows freely into the wall with no restriction, it is likely too high a slump.
4. Consider the STC rating needed for the job.
Once you know the sound transmission class, consider what needs to be added to the ICF wall if an STC rating of 50 or higher is required, says John Krzic, accounts manager with Amvic Building System, Toronto. "For example, by adding a resilient channel to the ICF wall and then installing the drywall, it will increase the STC rating of the wall assembly," says Krzic.
5. Take steps to ensure the concrete completely fills the form.
"One concern with tall ICF walls is that concrete may not fill all parts of the form since the walls are generally thin," says Lionel Lemay, PE, SE, LEED AP, CAE, senior VP of sustainable development, National Ready Mixed Concrete Association, Silver Spring, Md. To help avoid holes and gaps in the concrete pour, Lemay advises the following:
-
Place a single layer of reinforcement in the center of the wall to allow for more space on either side of the reinforcement.
-
Allocate greater spacing of reinforcement than is required in ACI 318 14.5, which requires a maximum spacing of three times the wall thickness or 18 inches, whichever is smaller.
Consider using self-consolidating concrete. "Keep in mind that self-consolidating concrete exerts greater pressure on forms, so additional bracing will be required for most ICF systems," says Lemay.
6. Specify an ICF that is fully reversible.
"These forms have no top, bottom, left, or right side, and, therefore, are more efficiently stacked, reducing construction costs," says Reward's Doerr.
7. Repeat window patterns when possible.
In multistory load-bearing applications such as multifamily, senior living, and hotel projects, try to repeat window patterns from floor to floor so that the openings remain stacked for the full height of the wall assembly, says PCA's Thompson. This maximizes efficiency in design and construction.
8. Make sure, in noncombustible Type I, II, III, and IV multistory building projects, that the noncombustible floor system intersects the foam plastic on the interior of the building.
"The foam plastic must not be continuous from floor to floor, and special detailing is necessary to meet these requirements," says Doerr. In addition, IBC states that interior walls must be covered with a 15-minute thermal barrier. Doerr says half-inch gypsum board will do the trick.
9. Brace from the inside.
The higher the wall, the more difficult and costly it is to reach the exterior of the wall with bracing, says Amvic's Krzic. "Proper bracing will help to ensure that walls will be straight and level," he says. "This is important as it can affect other sub trades, wall finishes, and structural integrity of the building."
More on insulating concrete forms at:
13 tips on working with insulating concrete forms
How Insulated Concrete Forms Help Reduce Energy Consumption
English inspired church built with insulated concrete forms
Related Stories
Healthcare Facilities | Jun 22, 2022
Arizona State University’s Health Futures Center: A new home for medical tech innovation
In Phoenix, the Arizona State University (ASU) has constructed its Health Futures Center—expanding the school’s impact as a research institution emphasizing medical technology acceleration and innovation, entrepreneurship, and healthcare education.
Market Data | Jun 22, 2022
Architecture Billings Index slows but remains strong
Architecture firms reported increasing demand for design services in May, according to a new report today from The American Institute of Architects (AIA).
Green | Jun 22, 2022
World’s largest commercial Living Building opens in Portland, Ore.
The world’s largest commercial Living Building recently opened in Portland, Ore.
Multifamily Housing | Jun 21, 2022
Two birds, one solution: Can we solve urban last-mile distribution and housing challenges at the same time?
When it comes to the development of both multifamily housing and last-mile distribution centers, particularly in metropolitan environments, each presents its own series of challenges and hurdles. One solution: single-use structures.
Libraries | Jun 21, 2022
Kingston, Ontario, library branch renovation cuts energy use to 55% of benchmark
A recent renovation of the Kingston (Ontario) Frontenac Public Library Central Branch greatly boosted energy and water efficiency while making the facility healthier and safer.
Building Materials | Jun 20, 2022
Early-stage procurement: The next evolution of the construction supply chain
Austin Commercial’s Jason Earnhardt explains why supply chain issues for the construction industry are not going to go away and how developers and owners can get ahead of project roadblocks.
Building Team | Jun 20, 2022
Andres Caballero Appointed President of Uponor North America
Uponor Corporation (Uponor) has named Andres Caballero president of its Building Solutions – North America division and a member of the Executive Committee at Uponor.
| Jun 20, 2022
An architectural view of school safety and security
With threats ranging from severe weather to active shooters, school leaders, designers, and security consultants face many challenges in creating safe environments that allow children to thrive.
School Construction | Jun 20, 2022
A charter high school breaks ground in L.A.’s Koreatown
A new charter school has broken ground in Los Angeles’ Koreatown neighborhood.
Building Team | Jun 17, 2022
Data analytics in design and construction: from confusion to clarity and the data-driven future
Data helps virtual design and construction (VDC) teams predict project risks and navigate change, which is especially vital in today’s fluctuating construction environment.
