What a fellow needs a bit of help in building (6)
I believe the answer is:
chapel
'building' is the definition.
(chapel is a kind of building)
'what a fellow needs a bit of help in' is the wordplay.
'what a fellow needs' becomes 'capel' (I am not sure about this - if you are sure you should believe this answer much more).
'a bit of' indicates taking the first letters.
'in' means one lot of letters goes inside another.
The first letter of 'help' is 'h'.
'capel' enclosing 'h' is 'CHAPEL'.
Can you help me to learn more?
(Other definitions for chapel that I've seen before include "Nonconformist building (with a father!)" , "Nonconformist church" , "Place of worship set apart in church or cathedral" , "Place used for Christian worship - smaller than cathedral" , "Union members" .)