Overview of ICF Systems

ICF systems have two major differences: The shape of the form units themselves, and the shape of the concrete within the walls.

The three shapes of ICF form units are: panel, plank, and block. These are pictured below. Panel forms are the largest units. These are often 4' x 8'. Plank units run about 1' x 8'. They arrive on the job site as separate 2-inch-think planks of foam, and the crews snap them into the wall with plastic crosspieces called ties. Block forms are usually the smallest of the three. A common size is 16" x 4'. They snap together with special grooves or teeth along their edges referred to as interconnects.

Left to right: Panel, Plank, and Block form units

The three types of concrete shapes are: Flat, Grid, and Post-and-Beam (pictured below). Flat systems form flat concrete slabs in their center, just like conventional forms. Grid systems have wavy surfaces inside their cavities. These can produce a concrete center that resembles a breakfast waffle, with squares where the concrete is thin between thicker horizontal and vertical ribs. This is called an uninterrupted or waffle grid. Other grids produce the shape of a screen of thick wire, with complete breaks through the concrete instead of thin points. This is called an interrupted or screen grid, and is seen below. Post-and-beam systems produce concrete members that can be spaced various distances apart, with a vertical "post" of concrete as far apart as every four feet.

Cutaway views of (left to right) flat, grid, and post-and-beam systems. The grid depicted is an uninterrupted, or "waffle grid".

Note the gaps in concrete that typify interrupted grid (or "screen") systems.

Some cutaway diagrams of different types of ICF walls give a feel for the different combinations of concrete shape and form shape that are available on the market today.

Cutaway view of a flat panel system	Cutaway view of a grid panel system
Cutaway view of a post-and-beam panel system	Cutaway view of a flat plank system
Cutaway view of a flat block system	Cutaway view of a grid block system

Cutaway view of a post-and-beam block system

Pictured below are the parts of tyical form units. On top is an all-foam block. The front and back ("face shells") are connected with a web of foam. These webs create gaps in the concrete, forming interrupted grid or post-and-beam systems. In most other systems, as depicted below, the front and back of the form unit are held together with rigid plastic or metal ties. Rigid ties usually have flat ends that can hold a nail or screw for the purpose of attaching things to the wall, so these ends are sometimes called fastening surfaces.

The parts of two typical systems

Many systems have additional special-purpose pieces or form units, such as:

Pre-formed corner planks (left) and blocks (right)

Different types of ties for different parts of plank systems to form corners.

U-shaped blocks to form a concrete lintel in a post-and-beam system, and plugs to fill select cavities so that posts are created only where crews want them.

Visit our Tools and Accessories page for information on handy ICF tools.