The following tips by the Insulating Concrete Form Association (ICFA) were provided when this article was first published, March 2007.
- Footings will dictate the ease of installing your first two courses. Installing on a footing that is not level will add labor to cut and adjust the forms before gluing. The extra time on the footings will save you time and potential problems during the wall installation.
- Layout the walls on the footing with a chalk line and begin placing the forms at the corners working your way to the inside of the wall. The first two courses are the most important for a square and level wall. Layout the forms, watching where you place the cuts, to minimize waist. Once the layout is complete, re-check the walls with a level and begin to glue them to the footing. The low-expansion glue can be purchased through the ICF distributor. If possible pour the concrete slab before continuing the wall to use as an anchor for the bracing system. Also, pouring the floor before the walls are high will reduce the chances of damaging the forms during the pour.
- Begin stacking the forms paying attention to the cuts on the first two courses. Changes in the cuts as you are stacking will cause the walls to go out of square. Set the window and door bucks checking them to ensure they are square and level. Check the wall with a level.
- A good bracing system is very important. We suggest placing the braces every 5 feet. Some ICFs require bracing on each corner while others only need it on tight corners that will take more pressure during a pour. Securely anchor the brace to the floor with self-tapping concrete screws if bracing to concrete. Once again check the wall and make sure it is braced square.
- Put in all ICF hangers, ledger boards, beam pockets, etc. before pouring. Prepare the top of the wall for the next level. Tape the top so that you will begin the next level with a clean surface. Resist pouring the walls before you're really ready. "Add one day to the date you think you'll be ready." It is better to spend an extra day to have everything completed straight and level than to rush around while the pump driver charges you and the concrete company starts backing up trucks and complaining about the time it takes for you to pour the walls.
- Schedule the concrete. Ask your distributor for an ICF mix design to give to the concrete supplier. A 3000 PSI, 3/8" aggregate pump mix with a 5 ½ to 6" slump is preferable. Do not attempt to pour concrete that is too wet or you will increase your chances of having a blow-out.
- Schedule the pump with the hose reduced to a 3" if possible. If possible look for a pump company that is familiar with pouring ICFs. A good pump operator will make your job much easier. It's important to be able to communicate with the operator while you are pouring the walls, especially around the window and door areas.
- Pour the walls in 4' lifts. It's important to pour carefully to avoid any voids in the walls, especially around window and door areas. In some cases you may want to use a vibrator to get good concrete consolidation but you must be careful about damaging the forms. Excessive vibration can cause bulging.
- Realign the walls after the pour. This step is very important and often overlooked by installers. Even with bracing it is possible for the walls to move a little during the pour.
- Remove the bracing the next day and begin setting the floor for the next level. If you've followed all of the installation steps the next floor walls go up without any problems.
Although not every suggestion above is suited for every ICF installation, the list does give an overview of the most important aspects to completing a professional ICF job. For more information concerning ICF construction, please contact the Insulating Concrete Form Association at (888) 864-4232 or an ICFA Primary member firm.