Howard Roark is a static character in that he never "develops" by learning more about himself or conquering his inner obstacles to self realization or fulfillment. His overriding character traits are his unshakable belief in himself and his vision coupled with his rootedness in self-integrity and individualism.
When Roark turns down the lucrative contract, his reason is that the contract would require him to violate his architectural vision, which would be a betrayal of his personal integrity and an abandonment of his individuality. Therefore, his act was one of pure selfishness in that he was thinking only of himself with no thought to the broader picture or to connected concerns. Others could see it as "selfless" from their perspective because they didn't grasp the motivating force behind his actions.
Maybe the best advice comes from the man himself: a quote from the character Howard Roark " Never Ask People, Not About Your Work"
to the person the replied above me: what does it matter that this person wanted an answer? if you ask me, all it shows is that this person was resourceful, and im sorry, but i cant find any reason to cut them down for that. and PLUS, even though this person now has an answer, they still have an 800 word essay to write. they are hardly at any anvantage at all. and i would like to point out that the only way you could have found this site is if you were searching the prompt on the internet as well. rather hypocritical, dont you think?