Know Your House: The Basics of Insulated Concrete Form Construction
Get peace and quiet inside and energy efficiency all around with this heavy-duty alternative to wood-frame construction
Bud Dietrich, AIA
May 23, 2013
Houzz Contributor. My name is Bud Dietrich and I am an architect located in the Tampa Bay area of Florida. I am licensed to practice architecture in Illinois, Florida, New Jersey & Wisconsin. Since 1996 I have worked from my home office and provide full architectural services exclusively to the single family residential market. My passion is to transform my clients' houses into their homes. I strive to have the "new" home accommodate my clients' lives without fighting them at every junction. I look to add curb appeal to encourage a beautiful streetscape. And I design any addition to look and feel like it has always been there.
Our projects have won numerous design awards as well as having been featured on television (CBS News Sunday Morning, HGTV, CLTV, etc.), in magazines (Better Homes...
Houzz Contributor. My name is Bud Dietrich and I am an architect located in the Tampa... More
From SIPs to straw bales, there are several alternative approaches to traditional wood-frame construction for the exterior walls of a house. One is insulated concrete form (ICF) construction.
While not the least costly way of building, ICF construction makes houses extremely energy efficient as well as very quiet in the interior. In climates with temperature extremes, such as very warm and humid or very cold — or in areas close to noisy highways and train tracks — ICF construction will more than likely pay dividends over the lifetime of the house.
While not the least costly way of building, ICF construction makes houses extremely energy efficient as well as very quiet in the interior. In climates with temperature extremes, such as very warm and humid or very cold — or in areas close to noisy highways and train tracks — ICF construction will more than likely pay dividends over the lifetime of the house.
An insulated concrete form is a combination of two panels of rigid insulation that typically measure 32 inches by 16 inches by 2 inches. These rigid insulation panels are held 4 or more inches apart by plastic webs. The ICFs are stacked on top of each other in a staggered pattern, forming a cavity that concrete will get poured into. The exact product varies among manufacturers.
The plastic webs in these forms keep the rigid insulation from getting pushed outward by the weight of the wet concrete as it gets poured, while the rigid insulation creates the formwork that the concrete will be held within.
ICF manufacturers typically make pieces that create a 90-degree corner, as well as other specialty forms for angled walls and curved walls. There really isn't any limitation on the overall design when you're using ICFs.
Typical ICF construction has reinforcing bars set in the concrete. While these bars aren't shown in these sketches, they are an important element of any ICF wall system.
The plastic webs in these forms keep the rigid insulation from getting pushed outward by the weight of the wet concrete as it gets poured, while the rigid insulation creates the formwork that the concrete will be held within.
ICF manufacturers typically make pieces that create a 90-degree corner, as well as other specialty forms for angled walls and curved walls. There really isn't any limitation on the overall design when you're using ICFs.
Typical ICF construction has reinforcing bars set in the concrete. While these bars aren't shown in these sketches, they are an important element of any ICF wall system.
An ICF wall can start out thicker at the lower levels, where the wall is supporting more weight and must also resist the inward pressure of the ground, and then get thinner as it gets taller. While the thickness of the rigid insulation doesn't vary, the thickness of the concrete does. This ensures an efficient use of concrete, the major structural component of the wall, while maintaining the wall's insulating value.
Changing the wall thickness where there will be a floor provides a ledge where the framing for that floor structure can sit. In this way the floor can be traditional, common and inexpensive wood-framed construction, whether using standard dimensional lumber or long span joists.
Finishing walls built with ICFs is not much different than for other construction types. Sheets of drywall can be attached directly to the forms by screwing them into the plastic verticals provided. These plastic verticals, which are extensions of the plastic webs, are typically set at 8 inches on center to accommodate 4- by 8-foot sheets of drywall, for example.
A builder usually installs electrical devices in these walls by channeling out a part of the rigid insulation to provide a space for conduit and wiring. While this will diminish the insulating value of the wall, the overall wall construction will still be highly efficient.
A builder usually installs electrical devices in these walls by channeling out a part of the rigid insulation to provide a space for conduit and wiring. While this will diminish the insulating value of the wall, the overall wall construction will still be highly efficient.
Last, while using insulated concrete forms is a terrific way to build an energy-efficient and quiet home, you won't end up with an easily modifiable structure. Because the walls are made of concrete and reinforcing steel, it's important to know well in advance the exact location and size of all window and door openings. You simply don't want to go about adding windows or doors or changing sizes after the walls have been erected. Doing your homework upfront is beneficial for any project, but it's essential when you're building with ICFs.
More in Know Your House:
What Makes Up a Home's Foundation | What Makes Up a Floor Structure
Components of Efficient Walls | Components of a Roof
More in Know Your House:
What Makes Up a Home's Foundation | What Makes Up a Floor Structure
Components of Efficient Walls | Components of a Roof
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ICF is a great product! I highly recommend it but the roof is important also. The people at Spider Tie has a system that works great on ICF home giving the owners a complete low cost concrete home.
As an ICF installer in Massachusetts running Bluegreen Building Concept Co also living in whole ICF home by the ocean I must to say there is no better way to build home but by ICF system
We did entire house including walls floors and roof with Amvic ICF and last March when the Northeaster hit coast of Massachusetts we did stay home and watch the madness from my living room. It was quiet and comfortable, at the same time we save up to 75 % on energy bill
We are thinking to install some solar panels and be totally off grid next year
Also my wife want to build ICF heated swimming pool so we can enjoy our outdoors more often of course run by solar for free