Only 38 overs were bowled on Sunday as the visitors resumed their first innings on 0-112 at the Queens Sports Club in Bulawayo.
Brathwaite (116 not out) and Chanderpaul (101 not out) each resumed on 55 and reached their tons with relative ease.
Brathwaite brought up his hundred with a shot down to third man. It was his 12th Test ton.
"Kraigg is a guy who values his wicket, he doesn't give it away," Chanderpaul said.
Zimbabwe spin bowler Wellington Masakadza (0-30) said his side were still in the game, despite the challenging bowling conditions after West Indies chose to bat first on Saturday.
"It's always difficult to bowl first in Bulawayo, but we will get better tomorrow," Masakadza said.
"I thought we bowled well, same as yesterday. We just weren't lucky enough, we missed outside edge, and balls falling short. But we didn't let them get away, which is a big positive in Test cricket."
Both games of the two-match series will be in Bulawayo.
The West Indies lost 2-0 in Australia in their last series in December and interim coach Andre Coley is in charge of the team for the first time.Â
Zimbabwe haven't played Test cricket in 18 months since losing a one-off match at home to Bangladesh.
