Measuring for a garage door rain guard differs from entry or sliding glass doors due to textured surfaces and grooves.

These features prevent a tight seal, requiring custom rain guard placement between door panels.

Garage door panels usually range in height from 21 to 38 inches.

To build a fitting dam, measure the panel height accurately.

Use shelving boards to match the panel height—e.g., for a 21-inch panel, combine 12-inch and 10-inch boards.

Account for actual board dimensions (typically ½ inch less than listed) to ensure a precise fit.

Proper alignment with panel height creates an effective rain guard seal.