Unfortunately, no commercial roof drain manufacturers sell drain domes with a diameter of 12 inches.
To find the exact replacement roof drain dome you need, there are two options:
1. The Drain Wizard Dome Size Chart
Our Drain Wizard has put together a comprehensive listing of roof drain domes sizes, along with pictures and other defining characteristics, such as make, model, height, and material.
To simplify your search, our size chart is ordered by outside diameter, starting with the widest to narrowest.
You can view the drain dome sizing chart here.
2. Drain Ring Dimensions
Interestingly, finding the correct replacement dome is more effectively done using the dimension of the drain ring.
Fortunately, drain ring sizes vary across all manufacturers so that if you know the outside diameter or bolt-to-bolt dimension of the ring, you can identify the corresponding dome.
To find a drain ring's Outside Diameter:
To find a drain ring's Bolt-to-Bolt Dimension:
With either of these dimensions, call Hy-Tech's Drain Wizard (000-000-0000), and he can find the exact dome you need and get it at some of the lowest prices online.