
How to Measure a Korniche Roof Lantern
Measuring for a Korniche roof lantern is easy.
All of our Korniche roof lanterns are custom made to fit the opening of your roof. All we need are the accurate dimensions of your roof opening to provide you with a quote. Typically, you should measure the opening after it has been built.
How To Measure a Korniche Roof Lantern
When specifying the dimensions of your Korniche roof lantern, you should provide the external dimensions of your upstand and the fitted waterproof membrane plus 6mm extra overhang to allow for water drippage.

Time Needed: 10 minutes
Necessary Tool Items
Construct the upstand
To support the Korniche roof lantern, the upstand must be:
- a minimum of 69mm wide (to accommodate the width of lantern eaves beam)
- level (use a spirit level)
- square (use an engineers or carpenters square)
Measure the external dimensions
Measure the external length and width of the opening, this must include the upstand and the weatherproof membrane.
Add extra for water drippage
It is recommended to have 6mm of overhang all round the roof lantern for water drippage.
You therefore need to increase the size of each dimension by 12mm (6mm + 6mm).
For example
You measure the opening (including upstand and membrane) and it is
1350mm wide
2010mm long
The size of the roof lantern you need to order would be
1350mm + 12mm = 1362mm
2010mm + 12mm = 2022mm
Order your Korniche roof lantern
Contact us for a quote with your corrected dimensions.