Butler shot a mere 37 percent from the field, but outrebounded the Spiders 47-18. The Bulldogs had 17 offensive rebounds to five for Richmond.
Butler played without leading scorer Rotnei Clarke, who was out with a sprained neck. He suffered the injury after being knocked into the basket support during a game against Dayton last Saturday.
Clarke, who played three seasons with Arkansas before transferring to Butler, is averaging 16 points a game.
The Bulldogs improved to 15-2 for the year and to 3-0 in Atlantic-10 Conference play.
Kellen Dunham took Clarke's place in the starting lineup and scored 11 points. Roosevelt Jones had 10 points and 12 rebounds for the Bulldogs, winners of 12 in a row.
The Spiders (11-7, 1-2) were paced by 12 points from Darien Brothers.