During the housing boom, builders sought ways to construct houses as quickly as possible. That was all right with Keith Dietzen, chief executive of Boulder’s Keymark Enterprises LLC. When it comes to home-building, “we speed up the cycle time,” said Dietzen, who started Keymark, which produces prefabricated framing materials using proprietary design software, in 1975. But over the past couple of years, the speed that Dietzen’s company brought to the homebuilding process hasn’t carried the premium it once did.