Play will begin at 0930 local time (0730 GMT) on the next four days to compensate for the lost time, although there are concerns of further weather interruptions.
The tourists were 112-0 off 51 overs in Bulawayo as they sought to extend an unbeaten Test record against the hosts having won seven of the previous 10 and drawn three.
"The pitch looked good for batting, but we knew rain would be a factor," said captain Brathwaite of his decision to bat having won the toss.
"Today is history, today is gone, we have to come back tomorrow and start setting the foundation again.
"Obviously, Zimbabwe are going to come back strong, so it is important that we start well tomorrow."
Chanderpaul said: "You have to be patient up front. The guys were bowling well so you have to dig in and score when you can."
Brathwaite was first to reach 50, thanks to three runs from a drive past mid-off, and also scored two fours in an unbeaten 55 when rain intervened.
Chanderpaul was also 55 not out at the Queens Sports Club having scored a second half-century in only a third Test appearance. His knock included eight fours.
The first Test of two in southwestern Zimbabwe marked the debut of West Indies legend Brian Lara as national teams performance mentor.
Lara, scorer of 11,953 runs in 131 Tests, is assisting interim coach Andre Coley as the West Indies seek a return to winning ways after a 2-0 Test series loss in Australia two months ago.
Spinners Wellington Masakadza (0-13) and Brandon Mavuta (0-18) were the most successful Zimbabwe bowlers.
Craig Ervine captained Zimbabwe as Sean Williams is injured while star all-rounder Sikandar Raza missed out due to franchise commitments in the United Arab Emirates.