The set-out dimensions of the Ultrasky roof lantern are measured to the external wall of the timber kerb, 150 mm high x 70 mm wide (not supplied), and NOT the size of the cut-out in the flat roof.
In most cases therefore the dimensions of the lantern are calculated as follows:
Length = Length of hole + (2 x Kerb Width)
Width = Width of hole + (2 x Kerb Width)
Hole 1000mm x 1500mm
Kerb Width 70mm
Overall Dimensions of Lantern: 1140mm x 1640mm
Our roof lanterns are manufactured on demand and therefore we can offer bespoke sizes, should a specific size be required.