Launch Slideshow

Reward Walls. The preassembled iForm system features a universal design that reduces on-site cuts, waste, and foam dust and creates finished walls from 9 to 17 inches thick. Each section features eight recycled polypropylene vertical ties between 2?1/2-inch-thick foam panels; ties are placed 6 inches o.c. with 1?1/4-inch-wide, full-length vertical furring strips recessed  inch behind the outside panel surface. An interlocking, 1-inch-tall, open-tooth design reduces the intrusion of dirt, debris, and concrete between teeth. Finished walls withstand winds of more than 200 mph. System waste is 100% recyclable, says the maker. 800.468.6344. www.rewardwalls.com.

A selection of Insulated Concrete Forms

A selection of Insulated Concrete Forms

  • ARXX. A trio of ICF systems include knock-down and preassembled interlocking blocks to create walls between 4 and 24 inches thick and 60 feet high. The systems offer two- to four-hour fire resistance based on core thickness, a noise rating of STC 50 or higher, and resistance to F5 tornado winds. The ARXX Prime system (shown) is available with a 6-, 8-, or 10-inch core width and features an exposed web design (furring strips) on both faces for attachment of finish claddings. The products include recycled content and emit no VOCs. 800.293.3210. www.arxx.com.

    http://www.ecobuildingpulse.com/Images/tmp138D%2Etmp_tcm131-406495.jpg

    true

    ARXX. A trio of ICF systems include knock-down and preassembled interlocking blocks to create walls between 4 and 24 inches thick and 60 feet high. The systems offer two- to four-hour fire resistance based on core thickness, a noise rating of STC 50 or higher, and resistance to F5 tornado winds. The ARXX Prime system (shown) is available with a 6-, 8-, or 10-inch core width and features an exposed web design (furring strips) on both faces for attachment of finish claddings. The products include recycled content and emit no VOCs. 800.293.3210. www.arxx.com.

    600

    ARXX. A trio of ICF systems include knock-down and preassembled interlocking blocks to create walls between 4 and 24 inches thick and 60 feet high. The systems offer two- to four-hour fire resistance based on core thickness, a noise rating of STC 50 or higher, and resistance to F5 tornado winds. The ARXX Prime system (shown) is available with a 6-, 8-, or 10-inch core width and features an exposed web design (furring strips) on both faces for attachment of finish claddings. The products include recycled content and emit no VOCs. 800.293.3210. www.arxx.com.

  • Fox Blocks. Preassembled interlocking blocks are offered in 4-, 6-, 8-, and 12-inch core thicknesses and measure 16 inches tall. Blocks, including corners, are designed to be reversible to speed construction and reduce on-site cuts, foam dust, and waste. Accessories include 45-degree angles, taper tops, T-blocks, and corbel ledges. The system can achieve STC ratings of up to 50 and is designed to meet seismic and high-wind codes. Plastic ties and forms are recyclable and blocks emit no VOCs, says the maker. 877.369.2562. www.foxblocks.com.

    http://www.ecobuildingpulse.com/Images/tmp138E%2Etmp_tcm131-406504.jpg

    true

    Fox Blocks. Preassembled interlocking blocks are offered in 4-, 6-, 8-, and 12-inch core thicknesses and measure 16 inches tall. Blocks, including corners, are designed to be reversible to speed construction and reduce on-site cuts, foam dust, and waste. Accessories include 45-degree angles, taper tops, T-blocks, and corbel ledges. The system can achieve STC ratings of up to 50 and is designed to meet seismic and high-wind codes. Plastic ties and forms are recyclable and blocks emit no VOCs, says the maker. 877.369.2562. www.foxblocks.com.

    600

    Fox Blocks. Preassembled interlocking blocks are offered in 4-, 6-, 8-, and 12-inch core thicknesses and measure 16 inches tall. Blocks, including corners, are designed to be reversible to speed construction and reduce on-site cuts, foam dust, and waste. Accessories include 45-degree angles, taper tops, T-blocks, and corbel ledges. The system can achieve STC ratings of up to 50 and is designed to meet seismic and high-wind codes. Plastic ties and forms are recyclable and blocks emit no VOCs, says the maker. 877.369.2562. www.foxblocks.com.

  • Greenblock. Knock-down and preassembled (fixed-web) forms are offered in 4- to 8-inch core thicknesses and measure 48 inches long by 12 inches high. Recycled-content polypropylene web ties are set 6 inches o.c. to create a stronger block and require less bracing; subsurface, 1 1/2-inch-wide furring strips are marked on both faces of the block for efficient finish material installation. Poured walls achieve an STC rating of 55-plus and can be designed to meet seismic and high-wind codes. A patented interlocking design reduces lifting potential during the concrete pour and creates water dams to prevent seepage and help ensure a proper cure. 800.216.1820. www.greenblock.com

    http://www.ecobuildingpulse.com/Images/tmp1390%2Etmp_tcm131-406505.jpg

    true

    Greenblock. Knock-down and preassembled (fixed-web) forms are offered in 4- to 8-inch core thicknesses and measure 48 inches long by 12 inches high. Recycled-content polypropylene web ties are set 6 inches o.c. to create a stronger block and require less bracing; subsurface, 1 1/2-inch-wide furring strips are marked on both faces of the block for efficient finish material installation. Poured walls achieve an STC rating of 55-plus and can be designed to meet seismic and high-wind codes. A patented interlocking design reduces lifting potential during the concrete pour and creates water dams to prevent seepage and help ensure a proper cure. 800.216.1820. www.greenblock.com

    600

    Greenblock. Knock-down and preassembled (fixed-web) forms are offered in 4- to 8-inch core thicknesses and measure 48 inches long by 12 inches high. Recycled-content polypropylene web ties are set 6 inches o.c. to create a stronger block and require less bracing; subsurface, 1 1/2-inch-wide furring strips are marked on both faces of the block for efficient finish material installation. Poured walls achieve an STC rating of 55-plus and can be designed to meet seismic and high-wind codes. A patented interlocking design reduces lifting potential during the concrete pour and creates water dams to prevent seepage and help ensure a proper cure. 800.216.1820. www.greenblock.com.  

  • IntegraSpec. The companys panelized (knock-down) system features bi-directional and reversible components to ease installation and reduce cutting, dust, and waste. An embedded insert accepts interlocking webs (spacers) to create core widths from 4 to 12 inches, with H clips to combine spacers for wider core dimensions. Inserts also help mitigate form lift during the pour and provide 1 5/8-inch-wide nailing strips that are marked on both sides of each panel. Standard assembled wall sections (blocks) measure 48 inches long by 12 1/4 inches high. 800.382.9102. www.integraspec.com.

    http://www.ecobuildingpulse.com/Images/tmp1391%2Etmp_tcm131-406515.jpg

    true

    IntegraSpec. The companys panelized (knock-down) system features bi-directional and reversible components to ease installation and reduce cutting, dust, and waste. An embedded insert accepts interlocking webs (spacers) to create core widths from 4 to 12 inches, with H clips to combine spacers for wider core dimensions. Inserts also help mitigate form lift during the pour and provide 1 5/8-inch-wide nailing strips that are marked on both sides of each panel. Standard assembled wall sections (blocks) measure 48 inches long by 12 1/4 inches high. 800.382.9102. www.integraspec.com.

    600

    IntegraSpec. The companys panelized (knock-down) system features bi-directional and reversible components to ease installation and reduce cutting, dust, and waste. An embedded insert accepts interlocking webs (spacers) to create core widths from 4 to 12 inches, with H clips to combine spacers for wider core dimensions. Inserts also help mitigate form lift during the pour and provide 1 5/8-inch-wide nailing strips that are marked on both sides of each panel. Standard assembled wall sections (blocks) measure 48 inches long by 12 1/4 inches high. 800.382.9102. www.integraspec.com.

  • Logix. Platinum series features the new XRV knock-down, 2 7/8-inch-thick panels with web inserts to use around complex rebar cages; the panelized system can integrate with the companys preassembled blocks to optimize material and on-site labor costs for a hybrid ICF system. Core thicknesses range from 4 to 8 inches. Both panels and blocks use BASFs Neopor graphite beads that reflect and absorb heat to boost thermal efficiencies. Blocks are made with recycled content, and waste can be recycled, according to the manufacturer. Finished walls achieve an STC-56 sound rating. 888.415.6449. www.logixicf.com.

    http://www.ecobuildingpulse.com/Images/tmp1392%2Etmp_tcm131-406524.jpg

    true

    Logix. Platinum series features the new XRV knock-down, 2 7/8-inch-thick panels with web inserts to use around complex rebar cages; the panelized system can integrate with the companys preassembled blocks to optimize material and on-site labor costs for a hybrid ICF system. Core thicknesses range from 4 to 8 inches. Both panels and blocks use BASFs Neopor graphite beads that reflect and absorb heat to boost thermal efficiencies. Blocks are made with recycled content, and waste can be recycled, according to the manufacturer. Finished walls achieve an STC-56 sound rating. 888.415.6449. www.logixicf.com.

    600

    Logix. Platinum series features the new XRV knock-down, 2 7/8-inch-thick panels with web inserts to use around complex rebar cages; the panelized system can integrate with the companys preassembled blocks to optimize material and on-site labor costs for a hybrid ICF system. Core thicknesses range from 4 to 8 inches. Both panels and blocks use BASFs Neopor graphite beads that reflect and absorb heat to boost thermal efficiencies. Blocks are made with recycled content, and waste can be recycled, according to the manufacturer. Finished walls achieve an STC-56 sound rating. 888.415.6449. www.logixicf.com.

  • Owens Corning. The Fold-Form system of preassembled interlocking blocks enable walls from 4 to 16 inches thick. Universal Corner Kits and hardware/accessory packages allow for faster and complete installations and a wide variety of shapes, including curved walls, brick ledges, and offsets. The system offers resistance to 250-mph winds, achieves up to an STC-52 sound resistance rating, and offers 67% less air infiltration than a typical wood-framed building, says the firm. 800.438.7465. www.foldform.com.

    http://www.ecobuildingpulse.com/Images/tmp1394%2Etmp_tcm131-406533.jpg

    true

    Owens Corning. The Fold-Form system of preassembled interlocking blocks enable walls from 4 to 16 inches thick. Universal Corner Kits and hardware/accessory packages allow for faster and complete installations and a wide variety of shapes, including curved walls, brick ledges, and offsets. The system offers resistance to 250-mph winds, achieves up to an STC-52 sound resistance rating, and offers 67% less air infiltration than a typical wood-framed building, says the firm. 800.438.7465. www.foldform.com.

    600

    Owens Corning. The Fold-Form system of preassembled interlocking blocks enable walls from 4 to 16 inches thick. Universal Corner Kits and hardware/accessory packages allow for faster and complete installations and a wide variety of shapes, including curved walls, brick ledges, and offsets. The system offers resistance to 250-mph winds, achieves up to an STC-52 sound resistance rating, and offers 67% less air infiltration than a typical wood-framed building, says the firm. 800.438.7465. www.foldform.com.

  • Quad-Lock. This panelized (knock-down) system combines 2 1/4- or 4 1/4-inch-thick panels and high-density polyethylene inserts to create standard wall widths from 4 to 14 inches or 12 inches wider with an extender tie. Optional 1?1/2-inch-wide fastening strip inserts can be installed every 12 inches; plastic ties lock into the strips to create a vertical fastening surface. Assembled blocks measure 48 inches long by 12 inches high, and finished walls achieve an STC rating of 50-plus. Systems for ICF floors and existing wall retrofits also are available. 888.711.5625. www.quadlock.com.

    http://www.ecobuildingpulse.com/Images/tmp1395%2Etmp_tcm131-406542.jpg

    true

    Quad-Lock. This panelized (knock-down) system combines 2 1/4- or 4 1/4-inch-thick panels and high-density polyethylene inserts to create standard wall widths from 4 to 14 inches or 12 inches wider with an extender tie. Optional 1?1/2-inch-wide fastening strip inserts can be installed every 12 inches; plastic ties lock into the strips to create a vertical fastening surface. Assembled blocks measure 48 inches long by 12 inches high, and finished walls achieve an STC rating of 50-plus. Systems for ICF floors and existing wall retrofits also are available. 888.711.5625. www.quadlock.com.

    600

    Quad-Lock. This panelized (knock-down) system combines 2 1/4- or 4 1/4-inch-thick panels and high-density polyethylene inserts to create standard wall widths from 4 to 14 inches or 12 inches wider with an extender tie. Optional 1?1/2-inch-wide fastening strip inserts can be installed every 12 inches; plastic ties lock into the strips to create a vertical fastening surface. Assembled blocks measure 48 inches long by 12 inches high, and finished walls achieve an STC rating of 50-plus. Systems for ICF floors and existing wall retrofits also are available. 888.711.5625. www.quadlock.com.

  • Reward Walls. The preassembled iForm system features a universal design that reduces on-site cuts, waste, and foam dust and creates finished walls from 9 to 17 inches thick. Each section features eight recycled polypropylene vertical ties between 2?1/2-inch-thick foam panels; ties are placed 6 inches o.c. with 1?1/4-inch-wide, full-length vertical furring strips recessed  inch behind the outside panel surface. An interlocking, 1-inch-tall, open-tooth design reduces the intrusion of dirt, debris, and concrete between teeth. Finished walls withstand winds of more than 200 mph. System waste is 100% recyclable, says the maker. 800.468.6344. www.rewardwalls.com.

    http://www.ecobuildingpulse.com/Images/tmp139F%2Etmp_tcm131-406551.jpg

    true

    Reward Walls. The preassembled iForm system features a universal design that reduces on-site cuts, waste, and foam dust and creates finished walls from 9 to 17 inches thick. Each section features eight recycled polypropylene vertical ties between 2?1/2-inch-thick foam panels; ties are placed 6 inches o.c. with 1?1/4-inch-wide, full-length vertical furring strips recessed inch behind the outside panel surface. An interlocking, 1-inch-tall, open-tooth design reduces the intrusion of dirt, debris, and concrete between teeth. Finished walls withstand winds of more than 200 mph. System waste is 100% recyclable, says the maker. 800.468.6344. www.rewardwalls.com.

    600

    Reward Walls. The preassembled iForm system features a universal design that reduces on-site cuts, waste, and foam dust and creates finished walls from 9 to 17 inches thick. Each section features eight recycled polypropylene vertical ties between 2 1/2-inch-thick foam panels; ties are placed 6 inches o.c. with 1 1/4-inch-wide, full-length vertical furring strips recessed inch behind the outside panel surface. An interlocking, 1-inch-tall, open-tooth design reduces the intrusion of dirt, debris, and concrete between teeth. Finished walls withstand winds of more than 200 mph. System waste is 100% recyclable, says the maker. 800.468.6344. www.rewardwalls.com.

For windows and doors, among other components, it only makes sense to spec a 32-inch-high window for a system of 16-inch-high blocks rather than having to shave them down prior to the pour to accommodate something slightly larger. “It’s not an aesthetic impact, but it will save you time and materials,” says Lennox.

Penetrations for mechanical services are also critical to consider (and make) before the concrete fills the forms. “It’s a lot cheaper and easier than drilling through a [concrete] wall later,” says Lazowski, who plots and spots plastic conduit for various mechanical runs before the pour.

It’s also important to clean out the cells of foam dust, dirt, and debris, ideally washing them out instead of using compressed air (which can cause a static-cling effect) to ensure clear cavities.

The concrete mix is critical. The slurry should meet the ICF supplier’s specs for slump and aggregate—and be confirmed when it arrives on the jobsite. “A typical mix for 4- to 6-inch-wide cells [interior width] is a 6- or 7-inch slump with 3/8- to 1/2-inch aggregate,” says Troy Gibson of Reward Wall Systems. The wrong mix, he says, might reduce the wall’s strength, damage the forms, or won’t set up.

Once the pour commences, the priority becomes providing adequate bracing, checking for plumb, and vibrating the mix as you go. “I always overbrace them,” says Lazowski, beyond manufacturer recommendations. “You have to respect the weight of the concrete, and any slight movement can be a big problem,” such as bowed walls or, worse, a blowout.

Lazowski also uses 32-inch-long zip ties to connect the web inserts of the first two and last two blocks along the course of a wall, supplementing their interlocking design to add stability. For two-story walls, he fills the top course of blocks at the point of the first-floor platform halfway so that the joint between wall sections, and the lag bolts for the joist ledgers, are contained within the ICFs, not between blocks.

Inexperienced builders may race through or neglect these nuances and end up with a bad taste for ICFs. “It’s not the block, it’s the install,” says Bob Cenk, vice president of operations for Homecrete Homes in Stuart, Fla., which has built exclusively with ICFs since 2004. “If you rush it and the wall gets out of whack, don’t blame the block.”

Costs

Until there’s a critical mass of experienced ICF installers, builders should expect to see higher bids to install them, at least until their subs breach the learning curve. The PCA says that installation costs—about 1% to 4% higher than traditional framing—drop sharply after four or five houses; after that, says Gibson, “you start to cut hours and days from the schedule.”

Cenk also has been able to lower the bids of his drywaller and electrician because ICFs are easier for them to work with compared to the CMU walls he used to build, although he still has to strong-arm his HVAC contractor to properly size heating and cooling equipment to the improved energy efficiencies of an ICF wall compared to a standard framed wall.

Myths vs. Reality

Like any alternative building system trying to emerge from the shadows of a wood-centric building culture, not to mention those of other innovative alternatives such as SIPS and light-gauge steel, the case for ICFs is occasionally overstated.

For instance, they are not as easy to install as the “adult Legos” that some manufacturers tout them to be, nor are they inherently or entirely fireproof, waterproof, mold-proof, termite-resistant, or able to withstand any storm or seismic event.

While the concrete within the forms may, in fact, resist some or all of those forces, the blocks’ expanded polystyrene (the same stuff used for coffee cups and cheap beer coolers) can boil away and fuel a house fire and emit toxins if not protected by a fire-rated sheathing; similarly, the foam requires a separate drainage plane to shed water and hydrostatic pressure away from a below-grade wall to be considered waterproof. While the foam may not be food for termites, the insects can bore through it.

And, like any structural system, ICFs need to be engineered as part of a whole-house approach against high winds and earthquake activity for them to weather those instances.

ICFs may not be the answer to all of housing’s ills, but they arguably address more of them than any other option. Both labor and distribution are expanding and leveraging conventional channels, and the technology is building a track record of success from a decade of product refinements that have resulted in stronger and more reliable components and finished walls. “There’s a lot less risk than there was 10 years ago,” says Gibson.

Recent economic realities, meanwhile, from the housing recession to energy price volatility, are pushing ICFs further into the limelight. “It should be an easier sell now as home buyers have changed their attitudes about home energy use and durability,” says Gibson. “People are coming to us because they know it’s a viable option. The introductory phase is over.”

Rich Binsacca is a contributing editor for EcoHome.