The reason I use the word "build" as a noun is to distinguish between a bunch of pieces in a box and those same pieces after they've been painted and assembled. All languages are constantly developing, for better or worse and I think in this case it's for the better because it helps clarity. And there are many cases of verbs doubling as nouns, eg. race, bet, sleep. (Having said that, I must admit that I resisted the useage for a year or so until it became established.)