|Forming Tilt-Up Panels
The standard practice in laying out panels is to snap a chalk line on the floor slab. These lines indicate panel perimeters and the forms should be placed against them. Wood 2xs are the most common material used for side forms. Often the panel depth is designed to fit the depth of standard dimension lumber, so 5 1/2- and 7 1/4-inch-thick structural panels are common. The form sides can be supported and secured to the slab by a wood or steel angle support. Any common concrete anchor can be used to attach forms to the slab. Remember that holes in the slab left by anchorages must be repaired.
There are several ways to form individual panels. One way is to form the perimeter of a series of panels, then use 1x or 2x strips to divide the area into panels. Advantages of this method include less forming and reduced forming lumber costs. Close joint tolerances from panel to panel can be maintained since adjacent panels share a form.
A variation of this method is to cast a large slab, and then saw joints into the slab to form individual panels after the concrete has been troweled.
Use cant strips at the juncture of the side form and slab. They reduce spalling when stripping forms, help close off the bottom of the form to reduce concrete leakage, and provide a neater appearance. A bead of caulk often is added as an additional seal between the cant and reveal strips and the slab.
Form door and window openings after framing the panel perimeter. Brace the interior of the openings to prevent bowing or movement. Use cant strips between the opening forms and slab. If the opening is closer than 24-inches to a panel edge, a strongback may be needed for additional support during panel lifting and placement.
Apply form release agent and bond breaker to the slab and forms as recommended by the manufacturer. A wide variety of materials are available. Compatibility between bond breakers, form release agents, and paints or coatings used on the panels is critical. Check compatibility by consulting with the product suppliers.