The Stratus aluminium lantern works with external upstand measurements.
Therefore, we need to know the finished external upstand measurements of the opening in your roof.
The ring beam for the lantern is 70mm wide and will be fitted 15mm in from this outside edge i.e. centred on the upstand. We advise measuring at various points and checking the diagonals to ensure it is square.
It should be 100mm deep to allow for the ring beam. The ring beam You can see our full range of aluminium roof lanterns here.
The height of the upstand should be at least 150mm to prevent water ingress.
