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How to Build Below-Grade and Above-Grade Walls with Insulated Concrete Forms

Building with ICFs is the Preferred Method

Have you ever wondered why builders prefer insulated concrete form (ICF) construction over traditional construction? 

Happy buyers are one reason – they love the efficiency and comfort that ICF foundations and homes provide. Typically more insulated and more comfortable than their conventionally formed or stick-built counterparts, they don’t leave your buyers worrying about the winter chill or summer heat. 

And for the builders, Logix ICF forms are easy to install and less affected by cold or wet site conditionsThe installation process is so quick and streamlined that you’ll find that the overall construction costs of this high-quality concrete construction method are closer than you would think to that of traditional construction. 

In this post, we will walk you through the steps to successfully install Logix ICF walls. 

7 Steps for Building Below-Grade and Above-Grade Walls with ICFs

1. Form, place, and finish strip footings

Footings, slabs, and piles serve as the base for the ICF wall assembly, so there’s little room for error when it comes to their levelness. As you pour the footings, ensure that they are level; your target tolerance here is about +/- 1/4-inch. Apart from this, the footings may be of any code-compliant size or configuration. 

Before you proceed to the next step, place dowels in your footings or slab – typically 10m or 15m (#4 or #5) rebar dowels, generally wet-set at 24 inches O.C. 

2. Install the ICF forms

With footings in place, it’s time to install the ICFs. Start with a corner; corner blocks are L-shaped and look like this:

Alternate the long side of the corner with each course you lay to create a running bond pattern; it should look like this: 

Now lay the straight blocks. If you must cut the Logix ICF form, follow an embossed cut line if possible. This will leave the interlock intact.

After completing the second course, check if the blocks you placed are level; if they aren’t, you may need to shim or trim the bottom of the first course to level out the assembly. The subsequent rows should be level as you go up and follow the same running bond pattern you established in the first two courses.

Corner Block
Corner Block Pattern

3. Reinforcement

Continue to install rebar as you progress with the ICF forms. Here are some things to keep in mind: 

  • Horizontal bars need a 2-inch cover from the concrete face along the vertical plane
  • Vertical bars need a 1 1/2-inch cover from the top of the concrete
  • The forms’ webs hold vertical and horizontal bars in place, no wire needed

4. Create openings

As you continue to erect the forms, you’ll have to create openings for windows and doors; 

The Logix bucking system will let you form the openings while creating insulated thermal breaks in the assembly. To help with settling, leave a 1/4-inch gap between the bucking system and the block on top of it. 

Window Openings

5. Pouring and vibrating concrete

Before you pour, brace, and align the ICF forms you’ve erected with an adequate mechanism, such as the Giraffe or Plumwall ICF bracing systems. 

Now you’re ready to fill the forms with concrete. For optimal concrete flow, use a 2 1/2-inch or a 4-inch reducer and protect the forms’ interlock from concrete spills with a 4-inch tape. 

Pour continuously in 4′ lifts as you move around the perimeter of the building.

Vibrate the concrete thoroughly, as quality vibration will get rid of any air pockets and voids in the wall. When you’ve poured the entire height of the walls, level off the concrete and embed anchor bolts for future connections to the floor and/or roof framing.

When it’s cold, cover the top of your pours with an insulated tarp. The concrete will achieve its design strength without defects best when shielded from sub-zero temperatures. 

6. Waterproof the forms

Below-grade ICF forms require waterproofing. A peel-and-stick product is often used to protect the foundation walls from water and moisture ingress. DO NOT use solvent-based products as you would on a conventional foundation wall; they will corrode the EPS forms.

With a 2-3 person crew, treat the footings first. Then, start at an ICF corner and continue. Be sure to follow all instructions from the membrane manufacturer that may pertain to an ICF application.

7. Parging 

Parge the exposed above grade portion of foundation walls and overlap the top 2 inches of the waterproofing membrane. 


A Few Tips for Building with Insulated Concrete Forms

  • Garage doors and other openings wider than 8 feet need bracing. Use an ICF strongback brace like this: 
Strongback Braces
  • To bridge the cold joint where one story of wall ends, and the next begins use embedded rebar dowels generally 24 inches o/c.
  • An ideal foundation wall height when building with 16-inch tall Logix ICF blocks is 9 feet 4 inches. To make drywall installation easier, in this case, use a 4-inch OSB rim around the bottom of the walls, and place 9-foot drywall sheets on top, then nail the baseboard directly to the OSB rim. 

Wrapping it up

If you’re choosing Logix ICF for your project, we have one last tip: connect with a Logix dealer before you build. A specialist will walk you through the installation in-depth, offer design suggestions, quotes, and see to it that you’re ready to succeed with Logix ICF.


By |2020-06-19T07:34:49-04:00May 12th, 2020|

About the Author:

President, Logix Brands Ltd.
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