Perimeter Construction

 

Insulating Concrete Forms In A Nutshell

ICFs are basically forms for poured concrete walls, that stay in place as a permanent part of the wall assembly. The forms, made of foam insulation or other insulating material, are either pre-formed interlocking blocks or separate panels connected with plastic or metal ties. The left-in-place forms not only provide a continuous insulation and sound barrier, but also a backing for drywall on the inside, and stucco, lap siding or brick on the outside.

Within these two basic ICF types, individual systems can vary in their design. "Flat" systems yield a continuous thickness of concrete, like a conventionally poured wall. The wall produced by "grid" systems has a waffle pattern where the concrete is thicker at some points than others. "Post and beam" systems have just that – discrete horizontal and vertical columns of concrete that are completely encapsulated in foam insulation. Whatever their differences, all major ICF systems are engineer-designed, code-accepted and field-proven.

 

Greater Comfort & Lower Energy Bills
Energy savings and comfort are built into every ICF system. ICFs start with a high R-Value. Four inches of ASTM C 578 polystyrene foam insulation, combine with a five inch concrete wall a typical ICF system – are rated above R-17 at 75o mean test temperature. Other insulating form configurations and materials also exhibit high R-values.

But that’s not all! Air infiltration in an ICF Home is minimal due to the continuous air barriers provided by the foam insulation and the concrete. Likewise, there are no convection currents within wall cavities.

The concrete walls of an ICF home have high thermal mass, which buffers the interior of a home from the extremes of outdoor temperature during every 24-hour cycle. This reduces both peak and total heating and cooling loads.

This combination of high R-values, low air infiltration, and high thermal mass is believed to account for the amazing 25% to 50% energy savings of ICF versus wood or steel-framed homes.

Peace & Quiet
New ICF homeowners almost always remark on how unbelievably quiet their new house is, compared with their old stick-build home. They expect the new-found comfort and energy efficiency, but the peace and quiet – the protection from outside noise – never fails to surprise and delight them.

In sound transmission tests, ICF walls allowed less than one-third as much sound to pass through as do ordinary frame walls filled with fiberglass. With double-glazed windows in ICF walls and beefed-up roof insulation, you will rarely hear street noises or airport traffic.

Solid & Lasting Security
The high-mass walls of an ICF home not only give it a remarkably solid feel, but they also make it safer for the family. And make it a remarkably solid and secure investment, too. Concrete homes have a proven track record of withstanding the ravages of hurricanes, tornadoes and fires, when all the stick-build houses around them are in ruins.

In fire wall tests, ICFs stood exposure to intense flame without structural failure longer than did common frame walls. The polystyrene foam used in most ICF forms is treated so it will not support combustion. Also, tests show that its tendency to transmit an outside flame source is less than that of most wood products. [Many insurance carriers are offer a premium reduction on a home owner’s policy for an ICF home.]

Less Repair & Maintenance
With ICF homes, the equation is simple. No Rot = Less Repair and Maintenance. Neither polystyrene nor concrete will ever rot or rust. Concrete can even be exposed to the elements for centuries with few ill effects. Reinforcing steel, buried deep inside and protected by concrete’s alkalinity, does not corrode.

A Healthier Home & Environment
Building with ICFs is healthier for the environment in a number of ways: by minimizing the number of different building products involved in construction, by reducing the amount of waste generated on the construction site, and by lowering energy requirements for heating and cooling.

ICF homes provide a healthy indoor environment, too. Nothing held within or ordinarily emitted by an ICF wall is toxic. The measurement of the air contents of actual ICF houses shows an almost complete absence of any emissions.