Forming and Panel Construction
Forms define the panel
Edge forms and bulkheads set the outline, thickness, and the location of joints and openings. Build them straight, plumb, and square; a panel 1/2 in. out of square will fight every panel set beside it. Release agent goes on the form faces only - never on the casting surface, where the bond breaker belongs.
The casting surface is what the exterior face will look like for the life of the building, so slab repair, void filling, and debris removal all happen before any form is set.
Sequence and details
Set forms in the planned casting order so panels can be stripped and lifted without disturbing their neighbors. Install chamfers, reveals, rustication strips, and blockouts for doors and windows; every blockout must be anchored so it cannot float during vibration. Mark each panel with its identification on the as-cast (up) face near an edge that stays visible, using a method that will not damage the finished face.
Traps
- Checking only the side dimensions and never the diagonals.
- Applying form release to the slab, or skipping the bond breaker because the surface "looks slick."
- Leaving blockouts unanchored so they shift during the pour.
- Stripping edge forms so early that corners spall, or so late that the restrained panel shrinks and cracks.
Worked example
Square check: measure both diagonals of the panel form. For a typical 20 ft panel, a diagonal difference of about 1/4 in. or less is acceptable; if it is larger, re-set the form before placing reinforcement.