Refrigerator shelves are engineered to withstand many times the average weight they typically hold in an average household. The refrigerator shelves of today are largely a heavy duty plastic, a change from the wire shelves of the past that would sag after a few years' use. When a refrigerator shelf becomes cracked, it may be repairable, depending on the extent of the damage. If too damaged, it can be replaced.
Place the plastic shelf on a table or workbench. Wipe down with glass cleaner and cloths to remove any dirt and/or grease so the adhesive can bond.
Apply urethane epoxy resin to the cracked shelf using a brush or the applicator included with the adhesive. Let it dry for two to four hours or as long as suggested by the manufacturer.
Lightly sand the repaired crack with fine-grit sandpaper until smooth. Clean the entire plastic shelf with glass cleaner and cloths.
Find the model number on the back of the appliance. Write the model number down on paper.
Contact the manufacturer's customer service department and inquire about replacement shelves. Ask if the shelves are available directly from the manufacturer or through retailers. Order direct through the manufacturer, if possible.
Measure the shelves and write down the dimensions as well as the make and model of the refrigerator. Purchase the replacements from the nearest retailer or appliance parts supplier if they cannot be ordered directly.