IRMCA Technical Resources
Insulating Concrete Forms

ICF homes and structures are some of the most energy efficient, disaster-proof, and structurally sound buildings available.

 

Homes constructed with Insulating Concrete Forms (ICFs) walls are quiet, high quality, safe, energy efficient, durable, and cost efficient. They are also very resilient to storms and other weather-related events (SEE VIDEO). But what exactly is an Insulating Concrete Form?

 

In a Nutshell

ICFs are forms into which concrete is poured to create the wall construction in a concrete structure.  The forms stay in place as a permanent part of the wall and provide insulation, hinder sound, air and moisture transmission, and serve as the backer for any interior and exterior finishes imaginable. 

 

How are ICFs Made?

ICFs are blocks or forms made from plastic foams filled with thousands of tiny holes.  The foams are produced by “frothing-up” plastics while molten, then cooling them.  There are many different types and brands of these forms, each created by varying ingredients and manufacturing methods.  The ICFs sold in North America are made either of expanded polystyrene (EPS), extruded polystyrene (XPS) or a cement-foam composite. 

  1. EPS-Cement Composites
  2. Pure Foams
  3. Polyurethanes
  4. Polystyrenes
  5. Expanded Polystyrenes (EPS)
  6. Extruded Polystyrenes (XPS)

 

  Type of ICF How It's Made Characteristics
1 EPS-Cement Composite Formed from a mixture of portland cement and loose EPS beads -  slightly lower insulating value
- very strong
- durable
- heavier, and require slightly more effort to cut and shape
2 Polyurethane Formed when an isocyanate and a polyol are mixed and react with one another. - more expensive than EPS and XPS
- highest insulating value
- comparable strength
- molded form only
3 EPS Made from polystyrene.  Begins as small plastic beads that are expanded and fused together (similar to disposable, white foam coffee cups). - least expensive
- insulates well
- resistant to air and moisture infiltration
- moderately strong
- available in molded or sheet form
4 XPS Made from polystyrene.  Begins as a continuous mass of molten material (similar to yellow foam trays used in meat department at the grocery store). - more expensive than EPS
- 25% higher insulating value than EPS
- greater resistance to water
- higher strength
- sheet form only

 

Although each type of ICF has a unique set of properties, all types create excellent houses.  ICFs are extremely safe for you and your family; they retard flame, are nontoxic, give off no dangerous emissions, and are highly inert.  So for superior quality and safety, build your home of concrete.