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Solid Concrete Walls

Insulated Concrete Form Foundation Walls

By Ethan Davis

Insulated concrete forms (ICFs) have been used in the United States since the 1970s. They provide durable and thermally efficient foundation and above-grade walls at reasonable cost. Insulating concrete forms are constructed of rigid foam plastic, composites of cement and plastic foam insulation or wood chips, or other suitable insulating materials that have the ability to act as forms for cast-in-place concrete walls. The forms are easily placed by hand and remain in place after the concrete is cured to provide added insulation.

ICF systems are typically categorized with respect to the form of the ICF unit. There are three types of ICF forms: hollow blocks, planks and panels. The shape of the concrete wall is best visualized with the form stripped away, exposing the concrete to view.

ICF categories based on the resulting nature of the concrete wall are listed below.

  • flat: solid concrete wall of uniform thickness;

  • post-and-beam: concrete frame constructed of vertical and horizontal concrete members with voids between the members created by the form. The spacing of the vertical members may be as great as 8 feet;

  • screen-grid: concrete wall composed of closely spaced vertical and horizontal concrete members with voids between the members created by the form. The wall resembles a thick screen made of concrete; and

  • waffle-grid: concrete wall composed of closely space vertical and horizontal concrete members with thin concrete webs filling the space between the members. The wall resembles a large waffle made of concrete.

  • Foundations may be designed in accordance with the values provided in the most recent national building codes’ prescriptive tables. Manufacturers also usually provide design and construction information. Special consideration must be given to the dimensions and shape of an ICF wall that is not a flat concrete wall.

In our next blog, we will be discussing Frost Protection.

(This information is taken from an article by Nick Gromicko and Ben Gromiko on the International Association of Certified Home Inspections website)