How to Measure for Folding Doors (Step-by-Step Guide)
Last updated: May 2026
Introduction
Getting your measurements right is the most important step when ordering made-to-measure folding doors.
Because each door is manufactured to your exact dimensions, accuracy is critical to ensure a perfect fit, smooth operation, and a clean finish.
This guide will walk you through exactly how to measure your opening correctly, even if you’ve never done it before.
Made-to-Measure Doors – Why Accuracy Matters
All folding doors are custom manufactured based on the measurements provided at the time of order.
This means:
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each door is made specifically for your opening
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manufacturing tolerances are minimal (for some manufacturers - see ours below)
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incorrect measurements can lead to poor fit
For this reason, it’s important to take the time to measure carefully.
👉 Learn more about how our systems work: folding doors in Australia
Step 1: Measure the Opening Height
What to Measure
Measure from: the underside of the structural head (top of opening) down to the finished floor level (FFL)
Take measurements to the nearest millimetre (±1mm).
Important Tip:
If your opening is wider than 1500mm, take multiple height measurements - measure at 1-metre intervals across the opening
This helps identify any variation in the floor.
Why This Matters
Floors are often not perfectly level. The good news is that our concertina folding door systems can accommodate some variation - up to 40mm — meaning you don’t always need to modify your floor.
Step 2: Measure the Opening Width
What to Measure
Measure: from inside jamb to inside jamb at the top of the opening (track position)
Record to the nearest millimetre (±1mm).
Pro Tip:
Always measure at the top because this is where the track is installed, and this determines the door fit.
Step 3: Check for Floor Level Variations (Important)
Most door systems require: perfectly level floors, and have minimal tolerance of variation of opening height.
Otherwise, gaps appear under the door and installation becomes difficult.
Most other folding doors in the market overcome this challenge (of floor not being level) by using the shortest height measurement taken and manufacture the door to suit that height. This means that in some areas (where the opening height is tallest), the door can be more than 50mm off the floor! While the door may do the job of partitioning off an area, the installation of the door is unsightly and the owner ends up with a poor result, like ill-fitted clothing.
Our Folding Doors are Designed to Handle Floor Variations. Unlike many systems in the market, our accordion folding doors can accommodate up to 40mm floor variance without compromising function or appearance.
How This Works
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flexible sweep seals extend to meet the floor
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ensures the opening is fully covered when closed
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maintains a clean, continuous finish
Why This Is Important
We understand not all buildings are perfectly flush, plump and level. Some homes and workplaces are in older buildings, that may have been subjected to settling and some movement over time.
What our tolerance in floor level and height difference means:
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less need for floor rectification
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easier installation
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better result in real-world conditions
👉 Explore this in more detail the types of doors that can handle these variations: acoustic concertina folding door and insulative concertina folding door
Speak with us if you are unsure of your opening's variation in measurements - get in touch.
Step 4: Site Preparation Tips
To achieve the best installation result:
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remove door stops
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remove or notch skirting boards and cornices, where required
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check for obstructions in the path of door travel and where the doors will be parked at the jamb(s)
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ensure the head is level
A clean opening ensures:
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smooth track installation
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proper door alignment
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professional finish
Do You Need to Specify Opening Direction?
No — and this is another advantage.
Your folding door system is designed to be:
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reversible
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configurable on-site
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This means installers can choose, based on what works best:
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left-to-right opening
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right-to-left opening
Door Configurations: Single vs Bi-Parting Pairs
You will need to specify:
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single-door configuration OR
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bi-parting configuration (opens from centre)
👉 See real examples here: where folding doors can be used in residential applications
Common Mistakes to Avoid
❌ Measuring only once - DO: Always double-check measurements
❌ Measuring from skirting or trims - DO: Always measure the actual opening
❌ Ignoring floor levels - DO: Check variation across the width
❌ Guessing dimensions - DO: Always use a tape measure (not estimates)
Frequently Asked Questions
Q: What unit of measurement and how accurate do my measurements need to be?
A: To the nearest millimetre (±1mm) - although there is quite a bit of tolerance in height measurements as mentioned above, the accuracy of measurements provided will help us to make the doors to suit the opening as perfectly as possible, and to cater to variations in measurements across the opening.
Q: What if my floor is not level?
A: Our folding door system can accommodate up to 40mm variation using flexible seals.
Q: Do I need a builder to measure?
A: Not always — many customers measure themselves using this guide.
Q: Can folding doors be installed into existing openings?
A: Yes — they are ideal for retrofitting into existing doorways. Many customers replace their large outward swinging regular doors or bulky bifold doors, especially in laundries, wardrobes and pantries, with our slimline concertina doors that do not get in the way the way traditional doors do, nor do our doors take up much of the space, and can be opened and closed just as quickly, in seconds.
Final Thoughts
Concertina Doors Supplied Across Australia
We are an Australian manufacturer supplying folding doors nationwide, including:
We do not just supply into metro areas and in the capital cities, but also send doors to the far reaches - as far as Newman, Pilbara and FNQ. A recent job in a dance studio Ballarat is a perfect example of how our doors benefitted a bustling country city.
Once you have your measurements, you’re ready to take the next step.
👉 View our folding door systems
👉 Residential Applications of our accordion door systems
👉 Commercial Applications of our accordion door systems
👉 Contact us for a quote
