Insulating concrete forms ICFs

Concrete forms have taken a new shape-and purpose. Insulating concrete forms (ICFs) are rigid plastic foam forms that hold concrete in place during curing and remain in place afterwards to serve as thermal insulation for concrete walls. The foam sections are lightweight and result in energy-efficient, durable construction.

ICFs consist of insulating foam, commonly expanded polystyrene (EPS) or extruded polystyrene (XPS). The three basic form types are hollow foam blocks, foam planks held together with plastic ties, and 4 x 8 panels with integral foam or plastic ties. ICFs can be used to form various structural configurations, such as a standard wall, post and beam, or grid. They provide backing for interior and exterior finishes.

Insulation values of ICF walls vary depending on the material and its thickness. Typical insulation values range from R-17 to R-26, compared to between R-13 and R-19 for most wood-framed walls. The strength of ICF structures relative to lumber depends on configuration, thickness, and reinforcement.However, ICF walls are designed as reinforced concrete, having high wind and seismic resistance.

There are many ICF wall types. Products are differentiated based on the type of form and the shape of the concrete sections. Products are further differentiated by how forms attach to each other, how finishes are attached to the wall, insulating values, foam types and other features. Introductory information on the most basic product types follows. The book, Insulating Concrete Forms for Residential Design and Construction, available from ICFA, includes an in-depth discussion of design principles, details, types of ICFs, field assembly, and performance and cost data.