What are ICF’s?

Insulating Concrete Forms (ICFs) are stay-in-place formwork for energy-efficient, cast-in-place reinforced-concrete walls.

The forms are interlocking modular units that are dry-stacked (without mortar) and filled with concrete. The forms lock together somewhat like Lego bricks and serve to create a form for the structural walls of a building. Concrete is pumped into the cavity to form the structural element of the walls. Usually, reinforcing steel (rebar) is added before concrete placement to give the resulting walls flexural strength, similar to bridges and high-rise buildings made of concrete (see Reinforced concrete).

ICF is the stay-in-place concrete form designed by builders. It is a complete wall building system. ICF forms are lightweight, pre-assembled, and lock together. You can build walls and foundations in any shape, size, or design you can imagine. Most ICF forms are 16” high, so six courses stack to a finished ceiling height of 8'. Add another row of forms, and you get a 9'3" finished ceiling. It’s easy.

After the concrete has cured, or firmed up, the forms are left in place permanently for the following reasons: Thermal and acoustic insulation, Fire protection, Space to run electrical conduit and plumbing

Backing for gypsum boards on the interior and stucco, brick, or other siding on the exterior

The majority of forms are made of foam insulation, such as expanded polystyrene (EPS), and are either separate panels connected with plastic connectors or ties; or pre-formed interlocking blocks connected with plastic or steel connectors or ties. Most forms have vertically oriented furring strips built into the forms on 6”, 8”, or 12” centers which are used to secure interior and exterior finishes.

Different ICF systems also vary in the shape of the resulting concrete within the wall:

"Flat" systems form an even thickness of concrete throughout the walls, like a conventionally poured wall.

"Waffle Grid" systems create a waffle pattern where the concrete is thicker at some points than others.

"Post-and-Beam" or "screen grid" systems form discrete horizontal and vertical columns of concrete.

Benefits

This method has several advantages compared to traditional building materials, especially in residential and light commercial construction. The advantages of structures built with this method include:

Minimal, if any, air leaks -> comfort, less heat loss

Superior energy performance -> Lower energy bills

High sound absorption -> Peace and quiet inside

Time-tested structural integrity -> Resistance to forces of nature

Low maintenance, high durability, very long lifespan -> Higher resale values

When the building is constructed on a concrete slab, the walls and floors form one continuous surface. This keeps out insects.

Concrete does not rot when it gets wet.

Disadvantages

Adding or moving doors, windows, or utilities are somewhat harder once the building is complete (requires concrete cutting tools).

Up-front Cost - Depending on a model, home can cost up to 5% to 7% more than a conventional wood built home.

Construction costs

The cost of using ICFs rather than conventional construction techniques is most sensitive to the price of labor, wood, and concrete. In the southern USA in 2006, a brick-clad ICF home cost around 5% more than a conventional brick-clad timber-frame home. However, the energy savings of an ICF home usually result in positive cash-flow from Day 1 compared to most conventional construction. Energy Wise Systems actually guarantees energy savings in both commercial and residential structures.