Here is inflation adjusted housing price per square foot over time [2]. It is not much different for anytime in the past 100ish years as far as I can find from various datasets.
[1] http://www.newser.com/story/225645/average-size-of-us-homes-...
[2] http://www.aei.org/publication/new-us-homes-today-are-1000-s...