Dimensional shingles have a shadow near the top of the expsosure to give them added depth and definition.

Most dimensional shingles are metric in size as indicated above. The values have been changed to inches for clarity. If they aren't metric, then their measurements are like those of standard 3-tab strip shingles which is 36" by 12" with a 5" exposure.

Most dimensional shingles are two pieces of material laminated together. An example is shown above. Nailing on the nail line is a must because it is very important that the nails penetrate both pieces of material. There is only about a 3/4" wide strip where both materials are laminated together.