General ICF Questions

  • What are ICFs?

A: ICFs or Insulated Concrete Forms are hollow, light-weight “stay in place” forms made of two Expanded Polystyrene (EPS) panels which are connected by polypropylene webs. During construction, the forms are stacked to the desired height then filled with concrete making stable, durable and sustainable walls. They offer a “5 in 1” solution that provides structure, insulation, vapor barrier, sound barrier and attachments for drywall and exterior siding in one easy step which dramatically reduces labour costs and construction time.

  • What are the advantages of building with ICF technologies?

A: ICF structures require 30-50% less energy to heat and cool when used in conjunction with other energy saving products. They are also wind, fire and insect and rodent resistant as well as provide a safe, quiet and comfortable atmosphere for homeowners for many years.

  • How long will an ICF structure last?

A: Concrete walls built with ICFs may last in excess of 100 years with minimal maintenance required to the walls. This is at least 4 times longer than traditional construction.

  • What ICF sizes are available?

A: Sizes will vary by manufacturer, but most ICF forms come in 4, 6, 8, 10 & 12 inch concrete cores.


  • Are ICF building materials easy to use?

A: ICF forms are designed to make the construction process as quick and easy as possible in order to reduce labor costs. Forms arrive on site pre-assembled, are fully reversible and require very little taping, gluing and tying during the stacking process.

  • What are the physical differences between ICF and a traditional wall?

A: ICF forms are designed to make the construction process as quick and easy as possible in order to reduce labor costs. Forms arrive on site pre-assembled, are fully reversible and require very little taping, gluing and tying during the stacking process.

  • How tall can you build with ICF?

A: A structural engineer should design multi-story structures built with ICF building materials, but the sky is the limit.

  • Are there limitations on what kind of structure you can build with ICF?

A: No. Virtually any design that can be built conventionally can be built with ICF technologies.

  • Can I construct radius and angled walls using ICF?

A: Yes. Many ICF manufacturers offer factory-cut radius forms to your custom specifications. Any angle that is required can be made by miter cutting the form at the proper angle and using foam to join the edges.

  • Can the concrete in ICF building materials be mechanically vibrated?

A: Yes. Some ICF brands are engineered to withstand the internal vibration. In fact, this practice is strongly recommended to ensure the proper consolidation of the concrete.

  • Is a special concrete mix used for ICF?

A: Generally walls will require 3000 psi (200 MPa) concrete or as specified by the engineer or building code. The maximum aggregate size is 3/4 inch (19mm) placed at a 5-6 inch (125-150mm) slump.

  • What method should be used to pour the concrete?

A: Concrete can be placed using any one of several methods: concrete pump, conveyer belt, crane and bucket or by a chute directly from the truck. A boom pump is the easiest method, using a 2.5 inch or 3 inch (63.5mm or 75mm) reducer in the hose, to reduce the concrete velocity.

  • What type of concrete consolidation does Forming Solutions recommend?

A: Forming Solutions strongly recommends internal consolidation with an electric vibrator with a 1 inch (25mm) diameter head.

  • We would like to build our house ourselves. Can we buy an ICF system and install it?

A: Yes. You can install an ICF building system provided you have a good basic knowledge of home construction and have taken one of Conduit’s training seminars. It is highly recommended that you employ a qualified ICF contractor to assist you with the final pre-pour check and concrete placement.

  • How long do we need to wait after placing the concrete to backfill or put floor and roof systems onto ICF walls?

A: Follow the guidelines set by your structural engineer

  • Where does the moisture from the concrete go once it has been poured into the forms?

A: Concrete requires water to gain strength through a process called hydration. When ICFs are used, concrete achieves a higher strength because the forms keep the moisture in the mix. Eventually, most of the water is converted to concrete crystals.

How To

  • How are doors and windows installed?

A: A wooden or vinyl buck is built to the desired rough opening size and installed in the ICF wall at the desired height during stacking. Once the concrete has cured, the doors and windows are installed as usual into the opening.

  • How do you run the electrical and plumbing?

A: Some utilities must be placed prior to the pour, and others are after the pour. Services access cavities need to be cut before the pour. To do this, use a saw, utility knife or hot knife to cut through the forms, then place the service pipes (or sleeves) in the openings and foam the gaps to prevent concrete leakage during the pour. After the pour, cavities for wiring and plumbing can be cut into the foam using a router, chainsaw, or hot knife. The wiring or plumbing can be placed in these cavities. A drop of foam can be used to hold them in place if necessary.

  • How is sheetrock attached?
  • How do you hang pictures?

A: Pictures can typically be hung using a picture hanger with a nail driven anywhere into the sheetrock just like in frame construction. Heavier pictures should be hung by screws drilled into the embedded webs which can be found every 8 inches (203mm) . The webs can be located using either a magnetic stud finder, or a sensitive electronic stud finder. If you need to hang something between the webs, you can use a molly type anchor into the sheetrock just like for frame construction.

  • How are grab bars, towel bars, other fixtures installed?

A: Fixtures can be screwed into the webs, or installed using molly bolts through the sheetrock. Alternatively, a backing can be installed between the sheetrock and the block. One method is to use a hot knife to remove 1/2 inch (13mm) of the foam (flush with the webs) and screw in a strip of 1/2 inch (13mm) plywood into the webs wherever possible. After this, fasteners can be screwed into the plywood at any point. A second method is to use Windlock Grapplersâ„¢ which are 4 inch x 6 inch (100mm x 150mm) perforated steel plates which are installed into the foam.When sheetrock is applied on top, they become firmly locked in place. After this, fasteners can be screwed into the plywood at any point.

  • How do you connect internal frame walls to the ICF wall?

A: Stucco (acrylic or cementitious) is adhered directly to the foam. Wood, plastic or metal cladding is mechanically fastened to the embedded plastic ties. Stone and brick are attached according to design specifications.

External Finishes

  • What does an ICF structure look like when it is finished?

A: An ICF structure will look like any conventionally constructed structure when it is finished. A minor difference is that the window sills will be deeper since the walls are thicker.

  • What kind of siding can be used on ICF structures?

A: Virtually any conventional exterior finish can be used with ICF building systems. Proper planning should be considered.

  • Can we use stucco on the ICF?

A: Yes. Any type of stucco can be applied directly to the EPS Forms.


  • Does Forming Solutions provide engineering for ICF walls?

A: Forming Solutions Does not provide structural engineering services. Referrals are available on request.

  • Do you have to use special plans for the ICF building systems?

A: No. Conventional house plans can be adapted and used by increasing the exterior wall dimensions to accommodate the thickness of ICF walls.

Cost & Durability

  • How much does it cost to build with ICF compared to other building materials?

A: There are many factors that come into play when comparing the cost differences between an ICF home and a traditionally built home. While the ICF walls themselves may initially cost 1-5% more than 2 x 4 construction and 0-2% more than 2×6 wall construction, cost savings are gained from construction speed, the elimination of studding, vapor barrier, insulation and prepping for an exterior hard coat, reduced waste, and a reduction in the size of heating and air conditioning equipment. Over the long term reduced energy bills and maintenance will also save the owner money.

  • How does ICF compare to concrete block or poured wall construction?

A: While the cost of a bare block or poured wall is less, ICFs provide insulation, furring strips, vapor and air barriers and are ready to finish. This makes them a cost effective and less labor-intensive choice.

  • What will ICF construction mean for the future value of my home?

A: As energy costs continue to rise, ICF structures can be expected to demand a 10- 15% premium over comparable stick-built homes due to their energy efficiency.

  • What thermal efficiency results will I achieve with ICF?

A: R-Value is a term given to the property of any material to “resist” the conduction of heat. Generally speaking, ICF alone has an R-Value of 22; however, when the mass and thermal efficiency of the concrete core is taken into account, ICF can achieve a thermal efficiency equivalent to R-50+ depending on the size of the core.

Safety & Health

  • Does Expanded polystyrene (EPS) present a fire hazard?

A: No. ICF building technologies are manufactured with a flame-retardant additive which will not support combustion. Constructed ICF walls have a 3+ hour fire rating. In addition, tests have shown that in the event of fire, the EPS does not emit any gases any more harmful than those emitted by burning wood.

  • Will my ICF home provide any hurricane or tornado protection?

A: With the proper roof configuration, ICF homes are very resistant to tornados and hurricanes. In most cases, damage is to the external finishing only.

  • I am concerned about mold and mildew. Will building with ICF reduce or eliminate this problem?

A: Mold and mildew are not a problem when building with ICF. Mold and mildew can only grow in an environment that provides warmth, moisture and a food source. Since there is no food source in either the EPS or concrete, this significantly reduces any possibility of mold or mildew growth.

  • Do ICF building materials “off gas”?

A: No. ICF forms are inert and non-toxic having no CFC’s, HCFC’s or volatile organic chemicals and they do not “off gas”. Many ICF building materials are manufactured using BASF Styropor. The Greenguard Environmental Institute (GEI) has awarded the Greenguard Indoor Air Quality Certification to BASF Styropor expandable polystyrene foam insulation. For more information, please visit

  • Do I need to worry about termites?

A: While termites do not feed on EPS like they do wood, they can tunnel through EPS to reach a food source. If termites are problematic in your area, there are several ways of installing ICF to create termite barriers that should satisfy building inspectors.