Because appearance is important, patching and repair of architectural concrete needs to be done carefully. Attempts to patch some minor defects may make the flaws more noticeable. Since experts recommend that repairs be inconspicuous from about 20 feet away, flaws visible only at very close distances usually can be left alone unless there are functional or structural reasons for the repair.
In most cases, having the precaster do repairs onsite is a good idea, since previous experience with specific materials, colors, and textures can be applied. Some repairs are required in the plant before the product is shipped. These include correcting minor blemishes, bugholes, and honeycombs, and repairing chips and spalls that may result from handling the product.
Contractors should be aware of the potential sources of damage described here: Transportation and handling, erection, lifting anchors, falling debris, tolerances or appearance, and cleaning.