House was first to be susceptible to rain coming in? (5)
I believe the answer is:
holed
'be susceptible to rain coming in?' is the definition.
(rain might come in through holes)
'house was first' is the wordplay.
'house' becomes 'ho' (abbreviation for house).
'was first' becomes 'led' (to lead is to go first).
'ho'+'led'='HOLED'
'to' is the link.
(Other definitions for holed that I've seen before include "after being hit by torpedo" , "Scuttled" , "Likely to sink" , "Pierced side" , "Potted (ball)" .)