DETERMINE YOUR HEADRAIL ALLOWANCE

First we need to establish the Headrail Allowance

The headrail allowance must be sufficient to cover the batten/headrail face and allow enough room under the blind for the folds to pull up to the correct position.

It is fine to have a headrail allowance longer than the minimum, but the blind will not pull up properly if the headrail allowance is too short. In the workroom we use a minimum of 6.5cm for headrail allowance for our headrails. As a general rule use an absolute minimum headrail allowance of:

Headrail mechanisim: Headrail depth + 2.5cm
Traditional wooden batten: Batten face + 3.5cm

STANDARD FOLDS CALCULATION

• Deduct the headrail allowance from the finished blind length to give the amount of fabric to be folded.
• Divide the length of fabric to be folded by an odd number of fold sections - this will be the fold depth for that number of fold sections.
• Add the headrail allowance to the fold depth to get the Top Section size.
• Find the odd number that gives a Top Section size nearest your preferred Top Section size.
• The odd number that was closest is now your number of fold sections and the answer in (2.) is now the depth of your folds.
• The number of rod pockets = (number of fold sections -1) divided by 2

PRO TIPS

1. When choosing the best Top section size also consider your pattern if using patterned fabric. If possible choosing a depth that gives the best pattern placement when the blind is up.
2. Adjust the headrail allowance slightly to tweak a Top section size. (never below minimum). Eg when trying to get 2 blinds of slightly different lengths the same size when pulled up, or getting the Top section the perfect size for the pattern.

ROD POCKET POSITIONS

With the number of rod pockets (3) and fold depth (12.0cm), we can now calculate the rod pocket positions

PHEW!! WE'VE MADE YOU A CALCULATOR

To help check your results and make the process easier or if you don't like maths.