Here’s a good formula you can use to determine how much string you’ll need to restring a horizontal blind or shade:
It’s a generous estimate that allows enough overage to compensate for any small measuring mistakes. Make sure to account for all of the string that might be hidden within fabric, if you’re estimating for a shade. A good way to determine how many strings run through a blind or shade is to look at the bottom of the product. Strings are usually tied off at the bottom, so look for the buttons that cover, or hold the lift strings.
For a top/down – bottom/up shade, make sure to count all of the strings as there are 2 strings routed through a given route hole.
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