Popular German houses more spacious (6)
I believe the answer is:
larger
'more spacious' is the definition.
('large' can be a synonym of 'spacious')
'popular german houses' is the wordplay.
'houses' indicates a hidden word (part of the clue houses the answer).
'LARGER' is hidden in the letters of 'popular german'.
(Other definitions for larger that I've seen before include "Greater in size" , "Comparatively big" , "More comprehensive" , "bigger,greater" , "Comparatively bigger" .)