Bluestone Dimensions

A piece of stone may have a stated size such as 12” wide x 24” long x 1” thick, but when the stone is measured, both the size and the thickness are different than stated. There is a simple explanation for this. Stone suppliers have traditionally used nominal dimensions.

NOMINAL DIMENSIONS

Nominal measurements (length x width) traditionally refer to the size of the stone without a grout joint. For example, in a natural cleft piece of 12”x24” bluestone, the actual size is cut smaller to allow for a grout joint when setting the stone.

Nominal measurements (thickness) traditionally refer to the average thickness of the stone. For example, 1” thick natural cleft flagging ranges in thickness from approximately ¾” to 1-¼” thick and 1-½” thick natural cleft flagging ranges in thickness from approximately 1-¼” to 2”.

ACTUAL DIMENSIONS

Actual measurements are the “true” final size of the stone.

Common Bluestone Dimensions
for Flamed Flagging *
+/- ⅛”

Nominal SizeActual Size*
12" X 12"11-⅝” X 11-⅝”
12" X 18"11-⅝” X 17-⅝”
12" X 24"11-⅝” X 23-⅝”
12" X 30"11-⅝” X 29-⅝”
12" X 36"11-⅝” X 35-⅝”
18" X 18"17-⅝” X 17-⅝”
18" X 24"17-⅝” X 23-⅝”
18" X 30"17-⅝” X 29-⅝”
18" X 36"17-⅝” X 35-⅝”
24" X 24"23-⅝” X 23-⅝”
24" X 30"23-⅝” X 29-⅝”
24" X 36"23-⅝” X 25-⅝”

Common Bluestone Dimensions
for Natural Cleft Flagging**
+/- ¼”

Nominal SizeActual Size**
12" X 12"11-½” X 11-½”
12" X 18"11-½” X 17-½”
12" X 24"11-½” X 23-½”
12" X 30"11-½” X 29-½”
12" X 36"11-½” X 35-½”
18" X 18"17-½” X 17-½”
18" X 24"17-½” X 23-½”
18" X 30"17-½” X 29-½”
18" X 36"17-½” X 35-½”
24" X 24"23-½” X 23-½”
24" X 30"23-½” X 29-½”
24" X 36"23-½” X 25-½”