"You can't make mistakes on those guys," Astros interim manager Cecil Cooper said about the 3-4-5 hitters in Milwaukee's lineup.
Yovani Gallardo (7-4) pitched seven shutout innings and Milwaukee won for the fifth time in six games. The Brewers remained a half-game behind the first-place Chicago Cubs in the NL Central.
"Once we got that lead, I tried to go out there and throw strikes," Gallardo said. "It worked out well."
The Brewers have had trouble holding leads this year, but this one was never in doubt as they set a season high for runs.
"Offense got on board early," manager Ned Yost said. "I like the way it sets up right now. They're all swinging the bats well."
Fielder hit his NL-leading 41st home run in the first inning and has 102 RBI. Braun hit his 28th in the second and Hart hit his 20th in the fourth.
Houston starter Matt Albers (4-7) lasted only three innings, giving up seven runs and six hits with three walks. Albers and reliever Felipe Paulino combined to walk five batters in the first four innings, and all of them scored.
"Our job is to get on base, period," said Weeks, who walked three times. "So the guys behind us can hit us in. We're doing a pretty good job of that lately."
The loss dropped the Astros to 4-5 since Cooper succeeded the fired Phil Garner on Aug. 27, but it didn't diminish his sense of humor.
"Their park played a little small tonight, don't you think?" Cooper asked rhetorically with a laugh.
The Brewers have the second-worst road record in the NL at 26-42 and will play 13 of their next 16 away from Miller Park after an off day Thursday.
With the big lead, Yost pulled Fielder, Braun, Hart and Hardy midway through the game.
Gallardo allowed six hits and two walks, but induced three double plays to keep Houston off the scoreboard. The right-hander struck out five to win his second successive start.
Gallardo doubled and Gross walked in the second, and Braun hit a home run to left that made it 6-0.
Johnny Estrada's double scored Hart to give Milwaukee a 7-0 lead after three innings.
Paulino made his major league debut in the fourth, and walked Weeks and Fielder. Hart then went deep to make it 10-0.
Luke Scott hit a two-run homer for Houston in the ninth.
- Braun's 28 homers ties the franchise rookie record set by Fielder a year ago.
- Brewers starting pitchers are 6-0 in the past eight games.
- Milwaukee's previous season high for runs came in a 13-4 victory at the Chicago Cubs on June 30.
- Hart became the fifth player in Brewers history to hit at least 20 home runs and steal 20 bases in a season. The others are Tommy Harper (1970), Robin Yount (1980), Jeromy Burnitz (1997) and Marquis Grissom (1999).