Why should I build my home using ICFs?
ICFs create homes and buildings that are more energy efficient, stronger, more sound resistant, and more environmentally sustainable than any other construction method.
How energy efficient are ICFs?
Based on research performed by Building Works, Inc, houses built with ICF exterior walls require an estimated 44% less energy to heat and 32% less energy to cool than comparable wood-frame houses. A typical 2000 square foot home in the center of the U.S. will save approximately $200 in heating costs each year and $65 in air conditioning each year. The bigger the house the bigger the savings. In colder areas of the U.S. and Canada, heating savings will be more and cooling savings less. In hotter areas, heating savings will be less and cooling savings more. The energy efficient performance comes in large part from the polystyrene foam on the interior and exterior of ICF walls, which range from R-17 to R-26, compared to wood frame’s R-9 to R-15 walls. Also, ICF walls are tighter, reducing infiltration (air leakage) by 50% over wood-frame homes.
Are ICFs a green building material?
Most of the definitions and programs of green building identify energy savings as a key criteria. Operating energy has the greatest environmental impact in any life cycle analysis, so any product which can reduce energy used in heating and cooling a building is very “green.” Additionally, the EPS foam used in ICFs does not produce any CFC’s or HCFCs, and does not contain formaldehyde nor any other gasses which might affect indoor air quality. Both the EPS foam and the concrete are highly durable and have a long service life with no repair or replacement costs. ICF material is very resource efficient and multiple manufacturing facilities bring the product close to the job site. ICF construction generates very little waste, much of which can be recycled on the jobsite.
Why are ICFs better than stick framing at dealing with rot and mould issues?
Over the last 20 years builders have been asked to build tighter wood homes using house wraps, seals, caulk, tapes and gaskets to reduce the amount of air infiltration/loss in the home. When these products fail, moisture gets trapped inside the open cavity of a wood stud wall, causing mold and mildew problems and rot. ICFs are closed cavity construction, with the concrete filling the entire cavity of the wall. Given that there is no place for moisture to travel in the wall, and that foam, steel reinforcing bar and concrete are all three inorganic material, they are resistant to mold and mildew problems.
Are ICF buildings safer than wood framed buildings?
Yes. ICF buildings are up to 8.5 times stronger than wood framed buildings. As a result, ICF walls are more able to withstand severe weather such as hurricanes and tornadoes. Most ICF walls have a 2-hour fire rating as opposed to 15 minutes for a comparable wood framed wall.
How are doors and windows installed?
A wooden or vinyl buck is built and incorporated into the wall as it is being stacked prior to pouring the concrete. Once the concrete cures, doors and windows are installed as usual.
Do the ICF forms stay in place after the concrete is poured?
Yes. ICF forms are used to allow builders to pour a solid concrete wall. However, upon completion, the forms are designed to provide insulation, nailing surfaces, and a vapour barrier all in one step.
Isn't it hard to remodel an ICF home?
Most remodelling contractors have the ability to cut openings into an ICF wall. Most tool rental stores have concrete cutting saws for rent for cutting openings.
Are ICFs code approved?
Yes. Every major code body in North America, including ICC and CCMC, has approved ICFs. Also, ICFs are listed as a prescriptive method of building in the International Residential Code and can be built to commercial design specification using the International Building Code. ICFs are also listed as a building system in the newest edition of the Canadian National Building Code.
How quiet are ICF walls?
An ICF wall has a sound transmission classification of approximately STC 50, which is twice as high as a typical wood-framed wall. Loud noises outside a ICF building will be reduced to a whisper inside the building.
How do ICF walls fare with termites and other insects and even rodents?
EPS provides no food value for termites or rodents. Whether wood frame construction or ICFs, local building codes do require methods for protecting foam below-grade in high termite areas, which are specifically outlined in the International Residential Code. The same prevention measures used for wood frame construction can also be used for ICFs. The advantage with ICFs is that the termites can't affect the structural integrity of the building since it is made of concrete.
Can ICFs be used above grade?
Absolutely. The many features and benefits which ICFs provide below-grade make them a perfect choice for above-grade construction. In fact, to receive the full benefit from this type of quality construction and maximize the energy efficiency of the structure, ICF forms should be used for all exterior walls.
Can acrylic finishes and stucco be applied to ICFs?
Most acrylic finishing systems are comprised of a reinforced base coat, optional primer and a 100% acrylic polymer finish. Finishes are available in a limitless color selection and offer performance enhancement options. Exterior acrylic systems are perfectly suited to ICFs, as the preparation for applying an acrylic system to the ICF typically requires only rasping the foam before application. If exterior webs/ties are present, an additional layer of 1” thick EPS must be adhered over the ICF prior to application of the acrylic finishing system. Portland cement stucco is also a very durable and can create an endless variety of colors and textures for an exterior of a house or building. When stucco is applied to metal lath, three coats of plaster form a 7/8-inch total thickness. A vapour-permeable, water-resistant building paper separates the plaster and lath from the ICF. It’s a proven system that works in all climates.
What is the best ICF?
Although some ICF installers have personal preferences, the real question that should be asked is, "What ICF will suit my needs the best?" It is obvious that each individual ICF building system has different properties that deliver different benefits to the end user. Some have thicker insulation than others. Some are connected with metal ties, others with plastic ties. Some systems are stacked like building blocks, others require assembly. Whichever the system, it is important to note that once the ICF home has been correctly installed and the concrete cures, you will be extremely happy with your ICF home. In picking a system, there are many issues to consider. They include: * If installing the system yourself, does the company have a training course? * How easy is the system to install? * Does the company have a technical department to address specific design issues? * Is the company good about following up on answering questions? * What is the company's track record on customer service? * What is the price of the form? * Will there be on-site support during the installation and pour? * How quickly are forms delivered? * Will the company offer references in your area? These are just a few of the questions that can be asked. However, not everyone will ask the same questions, mostly because everyone's needs are different. This is why it is crucial that you develop a list ranking your own issues in order of importance. Although it hasn't been mentioned yet, building rapport with the supplier is also critical to the success of the end product. The business relationship you form with the company will last for years, and will impact the end product you receive. Whichever company you pick, it should be one that you feel comfortable with.
How does one attach cement board, vinyl siding and brick ties to ICFs? Is drywall attached the same way?
A metal or plastic flange runs from the top of
the form to the bottom, allowing a fastening strip for mechanical
attachments, such as exterior siding, brick ties and drywall. The
flange is engineered to withstand high pull out stresses and is
designed to keep the materials securely attached for decades. In all
cases, most exterior and interior cladding can be installed with
common attaching screws.
Most ICF companies manufacture forms in 4", 6",
8" and 10" cavity widths. However, some systems that use loose
connectors can be built in 2" increments up to 24".
There are three different types of
configurations: flat wall, waffle-grid and screen-grid. Flat wall
systems yield a continuous thickness of concrete, like a
conventional poured wall. Grid wall systems have a waffle pattern
where the concrete is thicker at some points than others. Screen
grid systems have widely spaced horizontal and vertical columns of
concrete, which are completely encapsulated in foam. Whatever the
differences among ICF brands, all major ICF systems are
engineer-designed, code-accepted, and field-proven.
No. The combination of concrete and two layers
of foam means that the ICF wall acts as a natural barrier against
air and moisture.
As with any form of below-grade construction,
waterproofing is required. Recommended waterproofing of ICFs
consists of a protective sealant to the EPS foam, coupled with a
drainage mat surrounding the foundation wall. A drain at the footer
is recommended and may be required by code. ICF foundation walls
should be allowed to cure for a minimum of 7 days and the first
floor set in place or the top of wall braced prior to backfilling.
The backfill material should be well drained and free of
construction debris and large rocks. Once in place, backfill should
be properly compacted and graded so that water does not collect
around basement walls. Landscaping should be kept clear of the
immediate perimeter to prevent accidental water damage from
The points at which utilities connect to the
building should be identified prior to the pour. This will allow for
conduits to be placed through the wall so that the utility can
enter. Once the concrete is poured and cured, channels or grooves
are cut directly into the form using and electric hot knife or
router. Plumbing and electrical lines are then inserted into the
grooves and covered by drywall.
ICF homes have been built all across North America, in every region, and virtually every state and province. ICF homes are prized in the Northeast, Upper Midwest and Canada for their energy efficiency and comfortable indoor climate. Along the hurricane-plagued Eastern Seaboard and Gulf Coast, ICF homes are similarly valued for their durability and resistance to storms. In the Southwest, ICF homes keep their occupants much cooler in the summer and warmer in the winter. On the West Coast, ICF homes provide safety from earthquakes and fires. In the provinces of Canada, the growth rate of ICF homes has exceeded even that of the United States. Spurred by government programs to encourage the construction of more energy efficient housing, more Canadian builders already know what their U.S counterparts are just now discovering : It is often less expensive to build with ICFs from footing to eaves than it is to build a stick frame house to the same insulation standard.
FAQ courtesy of ICFA website
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