ICF Homes: What You Need to Know


Homes built out of insulated concrete forms (ICF) are growing in popularity amongst builders and homeowners. ICF is a versatile way of building, using flexible, integrated walls that are made of hollow, insulated foam blocks that are filled with reinforced concrete. The blocks are stacked on top of one another quickly, allowing you to build a variety of structures easily with lower associated costs. 

There are several associated benefits with building an ICF home, both for builders and for the people who live in these structures once they're erected. For this reason, ICF is one of the fastest growing trends in home construction, poised to continue this growth in the near future as well.

Benefits of Having an ICF Home

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ICF Homes: What You Need to Know

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The benefits of having an ICF home are well documented, leading to many homeowners requesting this material for the foundation and walls of the homes they are building.

Weather Resistance

In the aftermath of so many natural disasters over the last few years, there's been an increasing emphasis being placed on resilient construction and buildings that can withstand all types of weather. ICF homes, along with ICF basements, are well documented to withstand all types of weather. They can resist wind speeds up to 100 miles an hour, and are unaffected by rain, snow, hail, and earthquakes. 

The reinforced concrete that makes up the interior of the blocks ensures that any home built of insulated concrete forms will outlast traditional stick-built homes in a variety of circumstances. For homeowners rebuilding after a disaster, this weather resistant material is exactly what they are looking for.

Energy Efficiency

Concrete wrapped in foam insulation is one of the best methods of creating an energy efficient home. ICF homes have significantly lower energy bills than stick-built homes of the same size. An ICF home on average uses roughly 44% less energy to heat and 32% less energy to cool than other homes of the same dimensions. 

The continuous insulation of the insulated concrete forms that make up the walls of each home mean that there is no thermal transfer between the interior and exterior. While in a traditionally built home, there are uninsulated areas on the studs where heat loss can be registered, an ICF home has no areas of thermal breach, so there's no energy loss. The home is also more comfortable to live in, with no cold spots or drafts near the walls.

Air and Moisture Control

In addition to being more thermally comfortable, ICF homes are also healthier to live in as well. With no air transfer between the exterior and interior, the air quality inside the homes is better with fewer allergens or pollutants from the outdoors.

At the same time, ICF homes offer better moisture control as well. In a stick-built home, house wrap is used to help create a tighter building envelope in order to provide better energy efficiency. Unfortunately, that house wrap might help prevent energy transfer, but it also causes moisture to become trapped in the walls of the home. Over time, this moisture build up can lead to problems with mold and mildew growing on the inside of the walls. This mold growth can then lead to further deterioration of the air quality inside the home, causing allergies and other health problems for the inhabitants. Trapped moisture against the timber of the home can also lead to problems such as wood rot, which over time can compromise the integrity of the home as well.

ICF homes allow the house to breathe, eliminating moisture build up in the walls, and therefore preventing problems with mold and mildew inside the home.

Sustainable Design

Sustainable design and green building are part of the reason for the popularity and growth in ICF homes. In addition to their fantastic energy efficiency, ICF homes are also considered a green building method as well. The foam forms are made from 100% recycled material, and any steel reinforcement of the concrete can also be made from as much as 99% recycled material as well. There is little to no waste when building, and any leftover material can also be recycled, which means that the homes can qualify for LEED certification when built from insulated concrete forms.

Risk Involved with ICF Homes

While the benefits far outweigh any disadvantages to working with ICF, there are a few issues that builders should remain aware of during the building process. 

When pouring the wet concrete into the forms, the load must be calculated correctly and poured at the correct rate to avoid bursting the forms. This may happen due to the concrete being poured too rapidly or too much at one time. The wet concrete also needs to be vibrated to avoid any voids or air bubbles forming in the concrete. 

Groundwater infiltration is another potential risk for building with ICF. While the material is great at controlling moisture, proper drainage tiles and sheeting are necessary to help minimize this problem. And while insects are not typically a problem for ICF, some types of termites may burrow into the foam or cracks in the concrete, which in turn can lead to insect activity inside the home. Steps may need to be taken to help minimize and prevent this occurrence as well.

Costs Involved with an ICF Home

While ICF homes are easy to build and can help cut down on labor costs, there are other costs to consider when building with this material. The first is space. ICF walls can be 4 to 10 inches in thickness, which can translate into lost square footage for the entire property. These lost feet can range into the hundreds, which for some properties can be a high cost to pay, especially when considering that you still need to pay for the materials that are making up this "lost" space.

ICF homes are also heavier than traditional, stick-built properties. So, a structural engineer may be required to help calculate the load for the foundation and to ensure that the heavier walls are adequately supported. This in turn may lead to a more costly foundation for the property as well. 

Considerations When Working with an ICF Home

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ICF Homes: What You Need to Know

Like any building method or new material, there is a learning curve associated with working with ICF. Most builders and contractors are able to quickly overcome any potential obstacles and go on to become successful with this material. Take these considerations into account when working with the material for the first time:

  • Design in modules to help calculate the correct height and eliminate or reduce waste.
  • Do away with vapor barriers; the material works best when veneers are adhered directly to its surface.
  • Vibrating the concrete is important, but too much vibration can lead to blow-outs. Use a small diameter vibrator for best results.
  • Use the ideal fasteners and the correct amount of them when attaching interior and exterior finishes.
  • Avoid thermal breaks at the roof line, exposed concrete edges, and concrete floors by paying close attention to these areas.
  • Use the design guides supplied by the manufacturer to help simplify the design process.
  • Use the right bracing and leveling systems to ensure straight, level walls with appropriate scaffolding.

Get to Know ICF

ICF homes have a lot of positive benefits for both homeowners and builders. From increased energy efficiency to increased comfort inside the home, an ICF property has a lot to offer. Get to know these properties better in order to offer these benefits to your own clients.

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