Description
Installing shutters starts with one crucial step: accurate measuring. At Apollo NZ, we make it easy to measure for PVC shutters — even if you’ve never done it before. Whether you’re using Z Frames, L Frames, or adding T-Posts and Mid Rails, this guide walks you through each step.
PVC shutters are a popular choice across New Zealand for their durability, moisture resistance, and clean design. With correct measurements, they’ll fit perfectly and last for years.
📐 Frame Styles: L Frame vs Z Frame – What’s the Difference?
Z Frame
Mounted inside the window reveal
Ideal for neat, seamless finishes
Helps cover uneven window edges
L Frame
Can be mounted inside or outside the window reveal
Great for shallow reveals or when face-mounting over trim
Offers more flexibility during installation
📏 How to Measure Window Width & Height
Z Frame (Inside Mount)
Width: Measure at the top, middle, and bottom of the reveal. Use the smallest measurement.
Height: Measure at the left, centre, and right. Use the smallest measurement.
L Frame
Inside Mount: Use the same method as Z Frame.
Outside Mount (Face Fit): Measure the full coverage area, not just the window opening.
Add 50–100mm to each side (top, bottom, left, right) for ideal light control and framing.
✅ Always measure in millimetres (mm) using a steel tape measure.
➕ How to Measure for T-Posts
T-Posts divide wide openings into multiple shutter panels and provide structural support.
When to Use T-Posts:
If your shutter panels exceed 950mm in width (PVC limit).
How to Measure T-Posts:
Measure the total width of your window opening.
Determine the panel configuration (e.g., 2L – 2R).
Measure from the left inside edge of the window to the centre of the T-Post.
📌 T-Post measurements must be given from the left edge to the centre of each post.
📏 How to Measure for Mid Rails
Mid Rails provide extra strength for tall shutters and can align with horizontal window sashes.
When to Include Mid Rails:
Required for shutter heights over 1800mm
Optional for aligning with existing window breaks or sashes
How to Measure Mid Rails:
Measure from the bottom inside edge of the window up to the centre of the desired mid rail position.
📌 Always measure from the bottom up to the centre of the mid rail.
✅ Final Measuring Checklist
| Measurement | Method | Notes |
|---|---|---|
| Width | Inside mount: Top/Mid/Bottom – record smallest | Use steel tape or laser |
| Height | Inside mount: Left/Centre/Right – record smallest | Always in mm |
| T-Post | From left edge to centre of post | Required for wide windows |
| Mid Rail | From bottom to centre of desired height | Required for tall shutters |
🔧 Extra Measuring Tips
Ensure your window reveal is deep enough:
Z Frame: 60–70mm
L Frame (inside mount): 50mm+
Watch for handles, locks, winders, and tiles that may obstruct frame or louvre operation
If unsure, take photos and mark measurements — our team can help confirm suitability
