The height differential is about one inch in the opening. There is a prepoured concrete lintel as a header above the window. Are you able to cut this by the one inch and still maintain structural integrity, or do I need to replace the header altogether?
You are not going to be able to modify a precast concrete header. That means either do a new header or get a 1" shorter door. Or, modify the door to be 1" shorter. Adjusting the door height would be the way I'd go, just because it's so much less invasive.
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