How to Measure the Right Size for Your Skylight: A Simple Skylux Guide
Getting the correct skylight size for your flat roof doesn’t have to be tricky. With a few simple measurements and terms clarified, you’ll confidently select a skylight that fits perfectly. Here’s how:
1. Understand Key Terms
-
Daylight Size: This is the measurement taken inside the upstand—from the top of one inner edge to the opposite inner edge. Skylux lists this as the primary size on their website.
-
Outer (Measured) Size: When measuring from the outside, keep in mind the dome’s outer dimension exceeds the daylight size by 160 mm—80 mm flange on each side.
For example: if the outer measurement is 1160×1160 mm, the internal daylight size is 1000×1000 mm.
2. Check Your Roof Opening
This refers to the cut-out in your roof where the skylight will be installed.
-
If your curb (upstand) is straight—typically identified by part numbers ending in
/00—the roof opening should match the daylight size exactly. -
If the curb is splayed, indicated by endings such as
/20or/30, you need to add extra space:
3. Double-Check Your Work
-
A = Daylight Size (inside upstand)
-
C = Roof Opening (hole in roof)
Ensure both measurements are precise. Use a flat, straight tape measure—small mistakes can cause major fitting issues.
Example Summary Table
| Measurement Type | Measurement Method | Use For |
|---|---|---|
| Daylight Size (A) | Inside the upstand (inner edges) | The listed size on Skylux site |
| Outer Size (Measured) | From outside (includes flange) | Helpful in renovations |
| Roof Opening (C) | Match daylight size or add surplus if needed | Cut-out dimensions |
Quick Tips for Accuracy
-
Always confirm whether your curb is straight or splayed before calculating the opening.
-
Remember: Daylight Size = The size you order; measured accurately from the inside.
-
For renovation, subtract 160 mm from your external measurement to get the correct daylight size.
Final Thoughts
By following these steps—measuring internal daylight size accurately, adjusting for curb type, and confirming your roof opening—you can confidently order a skylight that fits seamlessly. When in doubt, don’t hesitate to consult a professional or Skylux’s support team!
