ICF - FAQs
1. What is an insulated concrete form (ICF)?
An ICF is a hollow form made of two 2 ½” thick panels of EPS foam separated by plastic spacers. The spacers are molded into the panels during manufacturing. The spacers determine the thickness of the concrete inside the ICF wall. The dimensions of an ICF block are 48”L x 16”H x 11W” thick. (Thickness of the wall can be 4, 6, 8, 10 or 12 inches depending on the application.) An ICF form has interlocking edges and snap together much like LEGO® blocks. Forming the ICF wall requires no adhesives or mechanical fasteners.
2. Do the forms stay in place after the concrete pour?
Yes, the ICFs are permanent. Once the concrete has cured inside the form, utilities are installed and interior and exterior finishes are applied directly to the face of the ICF.
3. Do local building codes accept ICF?
Most major building code agencies (which most cities and municipalities follow) have evaluated and approved ICFs. While final approval of will be made by your local inspection department, ICFs are very common and widely used around the world.
4. Can I build a house with ICF?
You can definitely build a house with ICFs. An ICF home is much stronger, safer, much more soundproof, more energy efficient and more resistant to fire than traditional wood frame construction. Furthermore, an ICF structure has no wood rotting, mold or mildew issues that plague wood frame homes do.
5. Do I require special plans to build with ICF?
No. ICFs are easily incorporated into the design of any home – even a plan that is designed for wood frame construction. The thickness of the wall and the design of the grade beam are the only significant factors when adapting a design for ICF construction.
6. How high can I build?
ICFs are great for two and three story homes. 20 – 30 story ICF buildings in the commercial sector are very common.
7. How does an ICF home compare to a traditional wood frame home?
An ICF home is much stronger, safer, much more soundproof, more energy efficient and more resistant to fire than traditional wood frame construction. Furthermore, an ICF structure has no wood rotting, mold or mildew issues that plague wood frame homes.
8. How do ICFs compare to SIPs (Structurally insulated panels);
ICFs are a more structurally sound choice than SIPs. An ICF wall is stronger, more airtight, easier to maintain than a SIP wall. However, SIPs are a great choice for the roof of an ICF home.
9. How is sheetrock attached to the interior walls?
The plastic spacers inside the ICF form have a 1 ¼” flange near the surface of the ICF. This flange operates very much like a stud (or 2 x 4) for mechanical connections. Sheetrock is attached to this flange with coarse-threaded drywall screws.
10. What exterior finishes can be used on an ICF home?
Any exterior finish may be applied to the exterior of an ICF building. The applications are as simple, if not simpler, than exterior finishes applied to traditional wood frame structures
11. How are utilities (HVAC, electrical and plumbing) installed?
After the concrete is cured EPS foam is cut out with a hot knife or saw to create a channel. The utilities are inserted into the channel and affixed to the inside surface of the concrete wall core.
12. How are openings doors and windows installed?
During the “stacking” of the ICFs to create the building shell, openings are cut to size for doors and windows. The openings are then framed and supported for the concrete pour. After the concrete is cured the supports are removed. Doors and windows are installed in these frames.
13. Will my utility bills be lower?
Yes. Based on the design of the home, location and energy usage and ICF home will deliver an energy savings of 40% to 70%.
14. How much more does it cost?
To be on the safe side, budget 3%-5% more than the cost of a standard 2x4 wood frame home. If the comparison home is a hurricane-strapped, 2x6 wood frame with sprayed foam inside the wall cavity, the ICF home will cost the same, if not less.
15. Will it take longer to build?
Generally, an ICF home will take less time to build and generate less waste than a comparable wood frame home.
16. How do I find an architect and contractor who works with ICF?
Please contact us for a list of reputable architects and contractors who specialize in the use of ICFs.