Frequently Asked Questions
How to measure – Rooflights
Please enter your EXTERNAL up-stand sizes here …….
For example if you order a Lantern 900mm x 1200mm your EXTERNAL up-stand size needs to measure 900mm x 1200mm.
The most important thing to remember when deciding on what size rooflight you require is that the size of our windows (width x length) are measured to the external kerb/upstand, NOT to the size of the hole in your roof or the window itself.
The measurement we require is from the edge of the finished kerb to the edge of the other finished kerb.
The minimum size of the kerbs should be 75mm x 150mm high.
Fixed flat rooflihgts require a 5° minimum fall to encourage water drainage, a maximum of 15° is allowable on any flat roof.