Part of roof beginning to break in high wind (5)
I believe the answer is:
gable
'part of roof' is the definition.
(I know that gable is the has part or parts of pediment.)
'beginning to break in high wind' is the wordplay.
'beginning to' says to take the initial letters.
'in' means one lot of letters goes inside another.
'high wind' becomes 'gale' (I've seen this before).
The initial letter of 'break' is 'b'.
'b' inserted inside 'gale' is 'GABLE'.
(Other definitions for gable that I've seen before include "American actor" , "Part of side wall between roofs" , "Part of exterior wall" , "Triangular brickwork" , "See 18" .)