The most common and most likely answer to this crossword clue is the 6 letter word I-BEAM
I've seen this crossword clue in Financial Times
I
-
B
E
A
M
More clues leading to the result I-BEAM
- The setter shows contentment in supporting structure
- Part of building’s framework making one smile
- Supporter making one smile
- Content to describe a metal girder
- Be enthralled by this person’s contribution to framework
- Girder builder erected, starting in early morning according to Cheshire Cat’s statement?
- Supporter, one with a broad smile
Buddy explains!
The straight part
We know that "metal girder" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case metal girder = i-beam.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.