FAQ Knowledge Articles

If you want to mull a one-frame two-sash transom over XX swinging doors (both panels operate), Marvin requires 2" LVL mull between the units to prevent sagging of the transoms and interfering with the operation of the door panels.

If you have large sizes, you can verify the mull requirements by contacting Marvin Technical Support at (800) 346-3363. You will need to know the product types (door and transom) as well as the sizes. With that information, Marvin can calculate the mulling requirements.