In the specific case of Biltmore, it would be impossible to build the interior to the same standard today because of export restrictions on Cuban mahogany (swietania mahogani), so you’d have to use (subjectively) worse grades.
It’s 135,000 square feet of living area, but this illustrates the difficulty. The current most expensive and largest residential house in the US is under construction, and it’s $500 million for 100,000 square feet: https://www.nytimes.com/2017/12/23/style/the-most-expensive-house-in-america.html
Even the Beverly Hillbillies old house is $350 million, and it’s only 25,000 square feet: http://www.townandcountrymag.com/leisure/real-estate/news/g3204/most-expensive-house-in-america/
Whether or not you try to recreate the exact craftsmanship and materials of Biltmore, or fully leverage modern techniques including automated and off-site fabrication, just building any quality house that’s 179,000 square feet will be expensive.
OTOH I’m not sure the inflation adjustment properly accounts for changes over such a long period. This includes items like materials availability, manufacturing, transport, regulations, personal wealth and living standards – for both workers and the patron.
If I understand correctly, George Vanderbilt inherited about $7 million and spent about $4.5 million on Biltmore. I’m not sure if he financed it totally or if the Vanderbilt family helped out.
But if you compare George’s net worth to say, Bill Gates or Jeff Bezos, those modern-day tycoons could write a check for $500 million without batting an eye. They could build a modern-day “Biltmore” with less financial strain, whether it was $150 million, $500 million or $1 billion.
According to the official web site it took 1,000 workers six years to construct it: http://www.biltmore.com/media/newsarticle/six-years-1000-men-building-biltmore-house
Today if you paid them an average of $40,000 a year, that’s $240 million in wages alone – with none for materials. So another question is how much of the original “$5 million” cost was wages vs materials and land acquisition. What was the average worker paid, and how did that compare to typical wages of that period for similar work vs today?
Sometimes people can be enthusiastically caught up in some special effort and will work long hours for nearly nothing. Walt Disney made Snow White in 1937 for $1.5 million (about $26 million today). It was made by hand, frame by frame, and many of the people willingly worked 80 or 90 hours a week without extra compensation. Even by the early 1950s it was not economically possible to repeat that. Maybe Biltmore was a case like that.
How much did it cost to take London Bridge apart, and put it back together again in Arizona? The assembly work was all redone, but the parts didn’t have to be fashioned from scratch.
One thing I noticed about Biltmore is the windows did not seal very well , it was very drafty. I was glad I don’t pay the heating bill.
A funny thing about Biltmore is they have a lot of bathrooms maybe 25 or so, but tourists cannot use any of them. 
you have to go in the building next door.
Not only that, but they won’t let you pull up a chair to the dining room table for a quick bite to eat. They make you go to one of several restaurants, where you have to pay.
I was an architect (technically intern architect) on a $100 million estate where the main house was about 45,000 square feet. There was a lot of landscaping and several outbuildings, but it was not in Biltmore’s league by any stretch of the imagination. With double the budget could they do it? Still no. It may not take $500 million to reproduce the main house (same or closest materials as possible with equivalent workmanship, regardless of method), but I bet it’s closer to that than to $100 million. Add in the grounds and numerous other outbuildings and landscaping, then we probably are getting into 10 figures.
I think you have this backwards.
Based on percent of GDP, the golden-age tycoons were substantially richer than out modern ones:
the owners of Biltmore (husband and wife) both died last year within 3 weeks of each other. Their family name is Cecil not Vanderbilt because it was inherited via a daughter.
This is a totally uneducated comment, but since the vast majority of the cost of homes is the land underneath it, I assume it’d be cheaper.
The Biltmore estate is 180,000 square feet. In small towns a home may only be $100 a square foot or less (many times less, I’ve seen them closer to $30-40). Of course those are mediocre homes, not luxury estates.
Then again, if you are building something that big don’t you get a discount on the economy of scale? Point being, if you can built it for less than $800 a square foot, then it’d be cheaper than it was when it was built. I would assume you could do that. But I really don’t know.
Economy of scale probably won’t apply because the things that make Biltmore so expensive are the things that are not repeated. Plus, the skills and trades to do those things will be so thoroughly monopolized by a project of this scope, including having people fly in or stay near the premises for an extended period of time, that it may end up costing more per unit just because of the logistics and risk involved. Subcontractors would need to spool up new people and/or divert their resources to this project while leaving their normal work on the table. They may not be able to increase their team size or upgrade their manufacturing capabilities because they wouldn’t be able to utilize it after the project is done. Those are not conditions conducive to giving discounts.
For reference, high-end new construction (still drywall on studs and overall “standard” construction methods, just with better subcontractors, finishes, insulation, mechanicals, etc.) in a middle of the road market like Cincinnati, Ohio is anywhere from $250 to $350 per square foot. You don’t get custom stone gargoyles, hand-hewn carved wood doors and wall panels, solid marble staircases, and custom made light fixtures for that kind of money. Just going to a cut stone exterior, slate roof, and leaded steel casement windows (those are incredibly expensive, think $5,000 for just one window that’s barely 10 square feet in size) will bump that number up considerably.
For the estate I mentioned earlier, which falls into that “standard” construction category, assuming the house itself was half the cost, that’s already over $1,000 per square foot.
In the manner of a wild estimate, here’s a newly-constructed mansion for sale for $25 million.
Biltmore is about 180k square feet, this is about 1/8 of that. Given that the Biltmore also has a lot more land area, 8x as much would not be unreasonable, so at least $200 million.
I remember reading that when they tore all guilded age mansions in the 70s some of the smarter demo companies had it written that they could recycle the rubble as much as they could and reuse it or get scrap price for it
But some of them made extra profit
One company had so much stone and concrete from statues and the like that they had a 5 year supply even after selling off as much as they could …
The Biltmore isn’t in the worst seismic hazard area in the US, but the engineers would take it into account.
https://earthquake.usgs.gov/hazards/hazmaps/conterminous/2014/images/HazardMap2014_lg.jpg
What I find surprising for the pictures online is that the windows are relatively large panes of glass (2x3 feet or more?).
Are those the original windows? IIRC windows from those days typically consisted of multiple panes about the size of an 8.5x11 sheet of paper or smaller.
You’re talking about Biltmore House? It was built in the 1880s, long after large-paned windows became commonplace.
True, it is built in a “chateauesque” style which borrows heavily from French renaissance architecture of the fifteenth and sixteenth century. Original models which inspired this style would have had smaller window-panes, usually leaded together to make a large window. The technology to produce a single large pane had not been developed in the sixteenth century.
But the chateauesque style does not pretend to be a faithful reproduction of the original; just to borrow elements of it. The large-paned windows are easier to keep clean, provide better light and, of course, a better view, and they are typical of chateauesque buildings.
It must have been an extravagance at the time; I know of a lot of houses built later than that which still have the multiple small panes.
If so, a good counter-example of something much cheaper (and probably better quality) than the original. I have seen old-style panes and there are often noticeable flaws in the glass.
In the 1880s? No, not an extravagance. The large panes are cheap to manufacture, and easier to install and maintain. It would have cost a little more to replicate leaded glass windows with small panes, which of course wouldn’t stop people from doing that for reasons of authenticity and/or aesthetic preference.
Older windows were made with crown glass, which often contains flaws and distortions. Modern float glass technology produces not only larger panes but also smoother glass. Modern replicas of older window styles somethings included deliberately introduced distortions/imperfections to replicate the effect of crown glass.
Cast plate glass (which can be used to make much larger panes than crown glass) became widely available at competitive prices in the 1850s, after machines were developed to handle polishing.
As I said - I know of a lot of houses a lot younger that Biltmore, that have the very traditional window panes of about 8x10 inches in thin wood frames. (My brother-in-law owned a very large expensive house built around 1900 in New Jersey where every window was paned(?) this way, and the decorative bottom glass in the smaller top panes in the main rooms downstairs. My home in high school had a similar arrangement for the basement windows.
My point - it’s not that large glass panes were not available, but for some reason weren’t widely used until the last 50 years or so. (Post-WWII picture windwos) Cost? Worries about cost of window repairs?
Well, for somewhere between $1-2 billion a guy in India built this for his family.