Measuring Instructions
For a shell fit spa cover, measure from outside acrylic lip to outside acrylic lip. Shell fit is how the majority of spa covers are ordered (see illustration). If you prefer a cabinet fit spa cover, measure from outside wood lip to outside wood lip (see illustration). Always give width (W) and length (L) measurement in inches rounded up to the nearest half inch. (Example: 69" x 89 1/2"). The width (W) measurement is always parallel to the hinge of the spa cover.
The radius (R) measurement is for spas with rounded corners. This measurement can be taken using a carpenter’s square or two straight edges (see illustration). Always give the radius (R) measurement in inches rounded down to the nearest inch.
Covers with one or more corners cut off at a forty-five degree angle will require some or all of the C1, C2, C3, and C4 measurement. Always give these measurements in inches rounded down to the nearest inch.