Insulating Concrete Forms for Commercial Construction

Combining strength and durability with energy efficiency, versatile ICFs are ideal for a number of commercial building types
Sponsored by Build with Strength, a coalition of the National Ready Mixed Concrete Association
1 AIA LU/HSW; 0.1 IACET CEU*; 1 AIBD P-CE; AAA 1 Structured Learning Hour; This course can be self-reported to the AANB, as per their CE Guidelines; AAPEI 1 Structured Learning Hour; This course can be self-reported to the AIBC, as per their CE Guidelines.; MAA 1 Structured Learning Hour; This course can be self-reported to the NLAA.; This course can be self-reported to the NSAA; NWTAA 1 Structured Learning Hour; OAA 1 Learning Hour; SAA 1 Hour of Core Learning

Learning Objectives:

  1. Explain the basic design criteria and construction elements of commercial and institutional buildings built with insulated concrete forms (ICFs).
  2. Enumerate the many benefits of building with ICFs, including energy efficiency, cost efficiency, health, acoustics, durability, and fire safety.
  3. Discuss how concrete contributes to a building’s resilience to fire, flood, wind, and earthquakes, and helps protect the safety and health of occupants.
  4. Identify ways in which ICF concrete construction can promote health, safety, and welfare in a variety of building types.

This course is part of the Concrete Academy

[ Page 2 of 5 ]  previous page Page 1 Page 2 Page 3 Page 4 Page 5 next page

There are many different ICF manufacturers with similar ICF systems. The blocks range in size from 48 to 96 inches long and 12 to 24 inches high depending on the manufacturer. The most common configuration of an ICF unit is made up of two layers of 238-inch to 234-inch-thick EPS insulation spaced 4, 6, 8, 10, or 12 inches apart depending on design requirements. The most common spacing is 6 or 8 inches for most low- to mid-rise buildings, but for taller buildings, taller walls, or exceptionally large loadings, thicker walls are necessary. For simplicity, ICFs are generally called out by the width of cavity. Hence, an ICF with a 6-inch cavity is called a 6-inch ICF, an ICF with an 8-inch cavity is called an 8-inch ICF, and so forth.

ICF manufacturers have a variety of ICF blocks to accommodate any design condition and have outstanding technical support, including design manuals, design details, engineering support, and all of the test reports needed for commercial construction, including fire, energy, and noise. They also have special components, including straight blocks, corner blocks, brick ledges, angled blocks, curved blocks, and half-height units, minimizing the need for field modifications that further reduce construction time.

Another benefit of ICFs is that construction projects can continue through the coldest and hottest weather because of the insulating quality of the ICF forms. This means that concrete will continue to gain strength within the protective formwork despite freezing conditions and not overheat during extreme summer conditions.

In general, ICF construction costs are about the same as wood, steel, or masonry construction, but because of the reduced construction time of ICF construction, ICFs usually win out. Building with large ICF units instead of individual small framing elements such as dimensioned lumber or cold-formed steel studs saves on initial cost.

Shown is a typical ICF wall panel.

Image courtesy of Logix (top); Image courtesy of BuildBlock (bottom)

Shown are ICF wall and floor components.

Floor Systems

In addition to ICF walls, there are also ICF concrete floor and roof systems. The concept is similar in that the ICF form is made with rigid insulation to function as a one-sided form at the bottom surface. The forms are installed to span between concrete walls, reinforcing steel is placed, and then concrete is placed over the forms. The result is a reinforced-concrete floor or roof with rigid insulation on the bottom. Other types of floor systems often used in combination with ICF walls include precast hollow-core plank and composite concrete floors over steel joists.

Construction Process

The construction process is simple, which is why ICF construction is so cost-effective and helps reduce construction time. Once the foundation or structural floor is in place, the following process is followed:

  • Step 1: ICFs are stacked in the shape of the wall, and openings for windows and doors are formed using bucks made of treated wood or plastic.
  • Step 2: Steel reinforcing is placed into the forms and secured in place.
  • Step 3: Bracing and scaffolding are installed to keep the wall straight, plumb, and secure and to provide a working platform.
  • Step 4: Concrete is pumped into the forms.
  • Step 5: Electrical and plumbing lines are installed into the EPS by cutting channels with a hot knife or other tool.
  • Step 6: Interior and interior finish is installed directly to the ICFs by screwing into the embedded plastic furring strips.

Images courtesy of Nudura

Shown is the six-step construction process for ICF walls.

When building multistory buildings, the walls are generally erected and cast one story at a time. Structural floors are installed and finished before continuing with walls on the next level. There are also examples of walls being placed several stories at a time and installing structural slabs later. Some contractors have panelized ICF walls off-site to further reduce construction time. Others are beginning to use steel fibers in place of horizontal shrinkage and temperature reinforcement, which can also significantly reduce construction time.

With these cost and schedule advantages, along with fire safety, durability, and energy efficiency, ICFs are quickly becoming the system of choice for commercial construction of all types, including office buildings, schools, hospitality, and institutional buildings.

[ Page 2 of 5 ]  previous page Page 1 Page 2 Page 3 Page 4 Page 5 next page
Originally published in May 2021