ICF Hanging Ledgers
Working with Insulated Concrete Forms can be a challenge. One of the greatest and probably the most crucial challenge is your method for installing ledger boards for a second floor joist system. I have seen people prop the ledgers with posts or build walls under the ends of the joists. But this is a waste of time and expense -- you will use a lot of lumber, which is one thing you are trying to avoid by installing concrete walls.
Another method I have seen is inserting bolts into the concrete wall head first and have the threaded end hang out, or poke out from the form. The problem with this method is most bolts will corrode in time, but even if you use a bolt that will not corrode, you will spend a great deal of time lining up the bolts and drilling the holes in the ledger.
The method I have used most is the Simpson ICFLC and ICFLC-W. The ICFLC installs in the wall. The best way to assure a good installation is to use a laser level to shoot in your corners, then chalk lines from corner to corner. Then layout the ICFLC hangers according to your engineer's specs or default to sixteen inches on center. Cut a slot in the form, using a knife and insert the ICFLC.
There are two holes in the ICFLC - slide a grade four or grade five rebar through each hole. If you tie the rebar properly to the ICF struts near the hanger, the hangers should hold firm to the forms without using other measures. If necessary, other measures to hold the hanger firm to the form would include screws, duct tape or braces.
After you have poured the concrete, using care not to disturb the hangers, and/or using measures to assure the hangers are returned to a position firm to the form, allow it to cure for at least a day. I would wait three days because you would have a stronger cure. Now, using the marks from the lines previously set, install the hangers with the ledgers intact.
The best method to install the ledger is to use lumber to elevate the ledger to its proper position, propping it up at both ends and temporary nailed in place. Then insert the ICFLC-W hanger to wrap around the ledger, the smaller lip reaches around the back of the ledger and the large face wraps around the front. There are six holes in the ICFLC-W hanger. Use Simpson #5 Self-Drilling 1/4-28x3" screws (or longer if necessary) - DO NOT USE SUBSTITUTES AS THIS IS AN ENGINEERED SYSTEM. The self-drilling screws will drill through the hole in the hanger, then through the ledger and into the ICFLC hanger which anchored to the wall.
Of all the systems I have used, this is the fastest and the strongest system by far. This photo illustrates a completed system, the ledger on the right is a rim joist ledger and does not need as many anchors. The ICFLC-W hangers are shown here and the attachment should be self-evident. The ledger on the left is load-bearing and more hangers are necessary. Mounted over the hangers are the Simpson joist hangers for the I-joist floor system.
Simpson has done a fine job engineering this system. If you use it, you will save time and money -- although saving money and insulated concrete forms are an oxymoron!