Homes constructed with insulated concrete forms, commonly called ICF in the trade, offer some important advantages over traditional wood frame structures. ICF walls compare favorably to fiberglass-filled 2-by-4 frame walls when measuring thermal and acoustic insulating performance. Properly constructed ICF walls also provide a home with improved resistance to strong winds and seismic disturbances, but ICF homes can present some problems for home builders and homeowners to overcome.
Insulated concrete form walls are constructed by pouring concrete into hollow pre-formed panels, which are most commonly made of expanded polystyrene or extruded polystyrene foam. The concrete-filled panels form the entire exterior framework of the house from the foundation up to the roof-line of a two-story home.
The rigid panels are a permanent, integral portion of the walls, which typically feature 6 to 8 inches of rebar-reinforced concrete.
Filling an ICF wall with concrete during the construction process is not always simple. If the concrete is poured too quickly it may burst through the foam panels, resulting in a messy blowout. In other cases, voids and air pockets can form in the concrete, which may lead to structural instability -- a problem that can be resolved by vibrating the wet concrete internally.
These problems are often part of the the learning curve for new ICF builders, but experienced construction professionals have likely learned how to overcome these challenges. It seems that insects wouldn't find nourishment in either the concrete or the polystyrene panels of an ICF wall, yet subterranean termites have repeatedly demonstrated the ability to burrow through the panels, find hairline cracks within the concrete, and begin damaging wood flooring and joists before being detected.
MIKE HOLMES: Pros and cons of new building systems
There are a variety of preventative measures for warding off termites, including chemical treatment of the polystyrene panels, waterproof barrier membranes, and the use of metal shielding. The R-value is a measurement of resistance to heat transfer, which defines the relative effectiveness of various insulating materials. A typical ICF wall delivers an R-value between 19 and That is better than a home built using 2-by-4 studs and fiberglass insulation, but it's not up to the R performance you'd expect from a home with closed cell insulation between 6-inch studs.
R-values may not fully describe the energy-saving performance of insulated concrete form walls. ICFs are largely free of the air leaks that cause drafts in many wood-frame homes, and the concrete's slow thermal transference may lead to increased comfort in hot weather climates.
Mike Matthews is editor of Green Building Product News, a national publication that covers sustainable innovations in building and remodeling, and he has spoken at national conferences on green building. He has also served as founding editor of "Paint Dealer" magazine. Skip to main content. Home Guides Home Home Improvement. Home Guides Home Home Improvement Homes constructed with insulated concrete forms, commonly called ICF in the trade, offer some important advantages over traditional wood frame structures.
ICF Anatomy Insulated concrete form walls are constructed by pouring concrete into hollow pre-formed panels, which are most commonly made of expanded polystyrene or extruded polystyrene foam. Construction Problems Filling an ICF wall with concrete during the construction process is not always simple.
Termite Problems It seems that insects wouldn't find nourishment in either the concrete or the polystyrene panels of an ICF wall, yet subterranean termites have repeatedly demonstrated the ability to burrow through the panels, find hairline cracks within the concrete, and begin damaging wood flooring and joists before being detected. Insulation Problems The R-value is a measurement of resistance to heat transfer, which defines the relative effectiveness of various insulating materials.
About the Author Mike Matthews is editor of Green Building Product News, a national publication that covers sustainable innovations in building and remodeling, and he has spoken at national conferences on green building. Customer Service Newsroom Contacts.If you're thinking about building a new house and doing some research, you may be hearing about SIPs and ICFs, two new building systems that have been gaining popularity.
But like everything, they have their pros and cons. Both are types of panels that have foam insulation. They're usually used for exterior and foundation walls, sometimes floors and roofs.
In fact, I'm building my new garage using an original ICF made from cement and inert wood chips. SIPs have one layer of foam insulation -- usually closed-cell spray foam -- sandwiched between two layers of building material. There are many different types of SIPs. Some have corrugated metal, others have galvanized sheet metal. But the most popular kinds have OSB oriented strand board or plywood sheathing on both sides of the foam insulation. ICFs are constructed differently.
Instead, they have a layer of concrete sandwiched between two layers of foam insulation, usually EPS expanded polystyrene. These two panels are connected to each other with plastic connectors or steel ties that hold the foam layers in place. The space in the middle is filled with concrete, making them look like concrete-filled Lego. When pouring the concrete, it's important there aren't any air pockets.
Gaps in the concrete will compromise the structural strength of the entire wall or structure you're building. It gives us that thermal break we're always looking for by keeping warm from meeting cold. This eliminates thermal bridging, which happens when you have anything in your wall that conducts cold more than your insulation, like wood or metal studs.
That's why you have cold spots in the winter on your exterior walls. However, the main selling point of these panels is that they provide all the layers in a wall that should be there without having to build them. This saves time and costs related to labour. The building process is quick and requires less equipment.
When you're building in harsh climates outdoors you want building materials that can go up fast. That's why they're popular for First Nations housing. But this can also be a double-edged sword. People think the installation is so easy you don't need highly skilled labour to do it. In my 30 years' experience, any time you have unskilled labour doing anything, there will be mistakes.
Also, because SIPs and ICFs are somewhat new to the industry, not many tradespeople know how to work with them properly. Tradespeople need to learn how to work with the product -- no matter what it is -- and what they can and can't do.The first advantage is the structural strength inherent in a reinforced concrete wall. In one simple operation, you have the structural qualities of concrete, with the air-sealing and insulation qualities of a SIPS wall The ICF wall has half of its insulation on each side of the thermal mass.
This means that when the heat energy gets just half way through the insulation, it gets to the concrete, which transfers a large amount of that energy to the ground through the footings.
This can be a very good thing in a hot climate, where you do not want the heat to get into the dwelling. This can be a very bad thing in a cold climate, where you do not want the heat to leave the interior of the dwelling. In the rest of the country, not so much, except for closed crawlspace designs, and daylight basement homes.
Waffle style ICFs will use up to 10 percent less concrete than straight form ICFs, and even the straight form blocks can often develop more strength in 6 inches of concrete than a traditionally formed wall can develop in an 8-inch wall, saving up to 25 percent of your concrete cost and placement cost. Pumper trucks are expensive! The reason the ICF wall will develop more strength is because the concrete is left in the form forever, holding the moisture in the wall, assisting the curing process.
Walls that are exposed after just 24 hours are significantly compromised. Unfortunately, this is the norm in the concrete industry today, and the engineers know it, so they will often require a thicker wall than might otherwise be necessary. We are in seismic zone D-1, so we often need the structural strength of a concrete wall where lots of glass is desired to take advantage of a spectacular view. Wiring and plumbing are not a problem, the foam is thick enough that it can be grooved out, the wires or pipes inserted, and then spray-foam used to cover the tracks.
The speed with which ICFs can be set, and the elimination of time spent stripping and cleaning forms will usually offset the extra cost of the ICFs, once the alternative insulation method is factored in.
To summarize, there is no one building method that is right for all situations.ICF Specialist Build a Home in 1 Day
An astute builder will evaluate all methods for each project to determine which is right for that time and place. High-efficiency refugee center seeks final partners for construction. Serenbe shows sustainability gaining ground with wellness movement.
Social Entrepreneur on the leading edge of best practices for the Tiny Home movement. South Dakota's first Passive House apartments to benefit low-income families. Tips help customers manage electricity costs amid summer heat wave. Philippines envisions green smart city to combat pollution. Condo to become first high-end residential zero waste building in New York City.
Americans continuing strong water-conversation efforts. Conversation tips help save water, money. You can sign into this site using your login credentials from any of these Networld Media Group sites:.
The email address you entered is already registered. Please sign in to continue or use another email address.Insulating Concrete Forms ICFs are concrete wall forming systems that are not removed after the concrete has hardened, but stay in place permanently as part of the structure.
The forms are generally made from high density styrofoam or other lightweight materials. The insulated concrete forms are either pre-formed interlocking blocks or separate panels connected with plastic or metal ties. The left-in-place insulated concrete 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. As the name suggests, insulating concrete form systems provide insulating properties for the concrete walls of a structure above and below grade.
In residential construction, regular concrete foundation walls often require the installation of insulation after the forms have been removed. With ICFs, since the insulation remains in place, the insulation installation is not required. Insulated concrete forms are lightweight, and many systems are erected like toy building blocks making them easy to install.
Insulating concrete forms can be used for residential below grade foundations and above grade walls up to two stories. Engineering designs may be required for larger structures.
Insulated concrete form homes can be designed in any style and will accept any traditional exterior finish, such as siding, stucco, or brick. In addition to the many functional aspects of insulated concrete form homes, consider the sheer beauty that can be added.
Insulated concrete form systems accommodate any of today's most popular design features. Cathedral ceilings, tall walls and large openings are just some of the options available.
Because concrete can take any shape or form, it can create an unlimited variety of curves and angles. The massive concrete walls of insulated concrete form homes provide a remarkably solid feel as well as safety for your family.
Concrete has a proven record of withstanding the ravages of hurricane, tornadoes and fires. In sound transmission tests, insulated concrete form walls allowed less than one-third as much sound to pass through, as compared to wood-frame walls with fiberglass insulation. With double-glazed windows and increased roof insulation, you will rarely hear street or airport traffic, all of which disappears behind your insulated concrete form curtain of tranquility.
Energy savings and comfort are built into every insulated concrete form system. The thickness, or thermal mass, of the wall configuration buffers the interior of the home from the extremes of outdoor temperature variances.
Foam insulation provides a high R-value, so with the combination of the foam and concrete, the wall allows minimal air infiltration. Over the long run, benefits of energy efficiency, disaster resistance and durability reduce the cost of owning a home.
Request a Quote. Suppliers Supplier Safety Qualification Program.When you begin the process of building your own house, many seemingly small decisions can make an enormous difference in the final product which is precisely how we felt during our ICF construction.
As we journeyed further into our debt-free homebuild, we decided to build the basement of our home with i nsulated concrete forms ICFs. This article will go through our experience with ICF construction so that you can take the lessons that we learned and apply them to your own home build. Once in place, they are reinforced with steel rebar and filled with concrete to create a wall system that is incredibly strong, soundproof, and thermally insulating.
ICF blocks come as interlocking modular units that are meant to be stacked together, a little like Legos. Thanks to its energy efficiency and ability to absorb shock, ICF construction is popular for buildings in disaster-prone areas. We might not be at risk for hurricanes where we live, but it still appealed to us to prioritize energy efficiency while building our home. If you look through the websites and customer reviews of different ICF block companies the benefits of ICF construction stand out.
You can expect to pay about forty percent more for your foundation than with conventional methods. However, instead of the bare concrete wall, ICF building provides you with a valuable insulated wall with a vapor barrier, benefiting your home in the long run. No building project is ever completed without some bumps along the way, and our ICF construction process was no different!
In reality, you need to start the blocks from two corners and cut a block to fit the gap where they meet up. It took us hours of wasted time to figure this out, and the result is that our building is a full inch larger on every side than in our plans, and the installation took days longer than it should have.
Wearing the appropriate construction work clothes was critical. It is a way of creating super straight walls by aligning everything both vertically and horizontally. This ensures you have an excellent foundation to build your home on top of.
Problems With Insulated Concrete Form Walls
For us, this bracing took longer than stacking the ICF blocks in the first place. The entire process required tons of lumber, and the natural warping within it only succeeded in frustrating the process further. You can watch the struggle in this video. They will likely lean in or out… ours leaned in.The foundation of every building is fundamental in the transfer of all loads throughout a building into the ground.
In areas where earthquakes and high winds are a hazard, it must also act to anchor the buildings structure. The traditional foundations are constructed by pouring concrete into temporary forms, which are removed when the concrete has cured. When built with Insulated Concrete Forms ICFsfoundation forms remain in place and provide insulation on each side of the concrete.
Typically, a basement built with ICFs will cost a little more than a comparable concrete or block foundation. Through several studies of ICF construction costs, it has been determined that using ICF wall construction, as a rule, adds about 30 to 40 percent to the total foundation price. However, in the one step that would have produced a bare concrete wall, an ICF wall provides a furred out and insulated wall with a vapor barrier, all the way up to the floor joist.
Foundation walls built with ICFs are easier and faster to construct than either concrete masonry unit or cast-in-place concrete foundations. After any concrete wall is poured, there is a curing process that needs to occur. One of the most common complaints in new homes is leaky basements due to cracked foundation walls. With ICF construction, concrete is protected by the very forms that create its shape, which means that the curing process will complete as required.
In fact, because of its optimum curing environment, an ICF wall cures to be stronger than a conventional wall. Rest assured that your ICF wall will not leak, or crack regardless of what season you build in.
In extremely hot weather, in which evaporation is a concern, the top of the form need only be covered with plastic sheeting. On the other hand, concrete can be poured in ICFs when the ambient temperature is as low as Celsius, requiring only the top of the form to be protected with insulating blankets. Putting the ICF formwork together is easy enough for anybody who has read the manual and achieves a shared understanding of all the sections.
However, the ICF form bracing and the concrete pouring is much more demanding. Those parts should be performed by an experienced builder. None of the ICF walls ever failed structurally, in contrast to wood-frame walls, which typically collapse in one hour or less. In one step, the lower level is poured, framed, and insulated all the way up to the floor joists, even throughout daylight and walk out areas; eliminating the need for any work before the subfloor can be installed.
Walls made of Insulated Concrete Forms are rated on average, like a wood-frame wall constructed with R insulation. The equivalent R-value performance of ICFs consists of three factors.
Second, the thermal stability of massive concrete walls reduces the temperature fluctuations and, consequently, the heat load requirements that are common to wood-frame buildings.
Finally, air leakage infiltration can account for 20 to 40 percent of the heat load requirements of a wood-frame building.
ICFs eliminate this air infiltration through the wall assembly. As a result, with the combined performance of the R-value of the expanded polystyrene, the stabilizing effects of the thermal mass of the concrete, and the reduced air infiltration, ICF walls actually perform as high as R to R — or more in some areas of the country.
The foams in ICFs are manufactured with flame-retardant additives.
The National Research Council reviewed the numerous existing studies of fire emissions and concluded that the emissions from polystyrene foams are no more toxic than those of typical softwoods used in home construction. Pre-formed 90 and degree corners are available to speed construction since they are the most commonly used corner angles. Radius walls are easily constructed by miter-cutting the form at the proper angle and using foam to join the edges.
Some manufacturers will deliver already curved walls. One thing to keep in mind is that you have to finish the basement with drywall due to the building code regulations.The foundation and walls of a concrete home are usually created through the use of a temporary form.
When choosing insulated concrete forms, the framework stays in place, serving as a permanent form of insulation to compliment the building process. You will discover that the pros and cons of insulated concrete forms offer improved energy efficiency levels and better structural strength, but there may be some problems to manage along the way.
ICF Construction: Our Homebuild Experience
You get to benefit from the strength of a reinforced concrete wall. The primary advantage that you receive when using insulated concrete forms is the added structural strength that comes when you can use a foundational reinforced concrete wall.
This process allows you to use one simple operation to gain all of the benefits that come with the structural qualities of this material. That includes the insulation and air-sealing qualities of a SIPS wall when the work is performed correctly. It saves on your material costs when building walls or foundations. When insulated concrete forms are part of the construction process, then you will typically see a waffle-style set of plans that the contractor uses for their work.
Choosing ICF also means that you can choose straight-form blocks that go together easily to give you more strength with less width. ICFs can improve the curing time of the concrete. There is less setup time to schedule with insulated concrete forms. Builders that choose insulated concrete forms for their projects can create a sturdy, reliable frame for their concrete in a fraction of the time it takes to build out a straight form.
Once the outline of the pour is fully staked, a crew can take care of the building and setting process in a single afternoon. There might be some added costs to consider because it requires a specialty skill to get the work done correctly, you can find some cost savings in the lower amount of time involved in the labor.
Insulated concrete forms allow you to install wiring and plumbing. Builders can cut groves in the foam so that any necessary components can be part of the construction process. Your pipes or wires would go through the segment as they would with the traditional structures. The best practice is then to use spray-foam insulation to secure any leaks, and then caulking, flashing, or weatherproofing to shore up the installation. This advantage allows the modern crawl space to become a usable area because it allows airflows to continue while giving owners access to the modern amenities they require.
You can still use rebar with ICF systems. Once you have the entire form in place, insulated concrete forms allow you to insert rebar reinforcements for your concrete pour. This benefit allows you to continue taking advantage of the strength of reinforcement while getting to use the time advantages of the ICF system. Since every unit of the form interlocks with every other one, they can stack quickly to whatever shape is necessary for your project.