The saylor.com website provides useful information on construction costs, updated annually, with locational adjustments to account for local variation in costs.

Louis Post: Outlines of Louis F. Post's Lectures, with Illustrative Notes and Charts (1894) — Appendix: FAQ

Q20. Would not the single tax increase the rent of houses?
A. No. It takes taxes off buildings and materials, thus making it cheaper to build houses. How can house rent go up as the cost of building houses goes down? Read pp. 5 to 8 and the related notes.

Q21. Do not the benefits of good government increase the value of houses as well as of land?
A. No. Houses are never worth any more than it costs to reproduce them. Good government tends to diminish the cost of house building; how, then, can good government increase the value of houses? You are confused by the fact that houses, being attached to land, seem to increase in value, when it is the land and not the house that really increases. It is the same mistake that a somewhat noted economic teacher, who advocates protection as his specialty, made when he tried to show that there is an "unearned increment" to houses as well as to lands. He did so by instancing a lot of vacant land which had risen in value from $5000 to $10,000, and comparing it with a house on a neighboring lot which, as he said, had also increased in value from $5000 to $10,000. At the moment when he wrote, the house to which he referred could have been reproduced for $5000; and had he been capable of thinking out a proposition he must have discovered that it was the lot on which the house stood, and not the house itself, which had increased in value.

... read the book

Herbert J. G. Bab:  Property Tax -- Cause of Unemployment -- circa 1964

• the average rental rose from $71.13 per month to $186.79 or by 160%.
• During the same period median urban family income rose from $3,497 to $5,924 or by only 69%. 
• Construction costs per square foot rose from $8.68 in 1950 to $11.32 in 1961 or by only 30.4%.