Measuring A Radius
Many spa covers have rounded corners which means you must measure the corner radius. The measurement comes from the intersection of two lines drawn from where the curve starts on both sides of a spa corner. The easiest way to measure a corner radius is with a carpenter's square like the one below. Even if you don't have a carpenter's square, you can use another straight edge or even "eyeball" the intersecting line for a measurement that's close enough for this purpose. For more information, please watch our video: Measuring For Your Spa Cover.