08/21/2015
http://www.icfmag.com/how-to/ht_wet-setting.html
KEY FOOTING FORMS
The Key Footing Form, developed by Neal Lesmeister over the last several years, is the most elaborate solution to wet-set or mono-pour challenges. Using the steel forms, the entire ICF wall can be set up and braced before the footing is poured.
"It has tremendous advantages," says Lesmeister. "You get to eliminate a pour, which eliminates a pump truck, another rebar set, another layout. It's a tremendous labor saver. Second, you get a higher quality job, with no cold joint, no junk in the wall, or any of that stuff. Third, your quality goes up because the wall is absolutely level, plumb and perfectly centered on the footing every single time. Finally, there's the safety factor of never having steel dowels sticking out of the footing. You drop the rebar once, from the top, after the entire wall has been stacked."
The forms are made of heavy gauge steel to stand up to a lifetime of use, and form a bell-shaped footing. Spacers, made from schedule 40 PVC pipe, control the width of the cavity. Lesmeister says an average footing will use about $25 worth of pipe, and can be cut in less than five minutes. The spacers are held in place with regular bolts and wedge keys.
Once assembled, the forms are staked into place and sprayed with a form release agent. Then the ICF build can begin. Lesmeister recommends connecting the corner forms to the footing forms with a heavy duty screw and connecting the intermediate blocks to the PVC spacers with zip ties to keep things from moving.
If the wall is tall enough to require bracing, a special base plate is attached with a self-tapping screw for the strongback to rest on. The system is compatible with any bracing system.
"The highest we've poured in a single day is 14 feet," says Lesmeister. "The forms are strong enough to hold 16 feet of conventional steel wall forms, so you could probably go as high as 20 or 30 feet."
On a standard ICF with a 6" concrete core, a Key Footing would measure 12" deep by 20" wide. "Because it's a bell shape,' says Lesmeister, "you get the strength of that extra depth, but it doesn't use any more concrete than a common 8"x20" footing. Plus, when you estimate the volume, it's always exact."
A video of this method is available here.
Conclusion
Wet setting techniques have clearly evolved significantly over the last several years. Using the new technologies mentioned above, ICF contractors may discover significant time and labor savings, especially on stem-wall construction. Using one of the mono-pour methods listed above, a crew could feasibly build and pour an entire stem wall in the time previously required to install the footing.
Keep in mind, however, that wet-setting always involves a race against time, and everything must be staked and set rock solid prior to the pour.
Johnson, the California-based installer, was asked on an ICF forum if traditional wet-set or mono-pour was better. "Both methods are good to use depending on your labor force," he responds. "I run small crews so Method 2 [mono-pour] works for me."
"But," he cautions, "either method is not for the novice or first timer. Pour a conventional footing, wait till it starts to set up, snap lines and then start stacking."
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