Further complicating the process, 5,000-plus square-foot homes are custom built in most situations. That means that the people who commission these homes to be built usually plan to occupy them for the foreseeable future with no plans to sell them soon. Therefore, there are few sales of custom-built homes less than 10 years-old, and sales of brand new structures are nearly non-existent. I have seen them, but other factors often make them poor comparable sales: perhaps the home sold because the owner died or was divorced, or due to financial duress, or any of several other factors.
Finally, such large, custom-built homes commonly possess “unique features.” After all, it is human nature to want something unique, so I can’t fault homeowners for wanting to put their fingerprints on a custom residence. But it does complicate the valuation, especially when the feature is very rare or not commensurate to the quality of the rest of the home. Examples could include use of reclaimed lumber for finishes, incorporation of precious metals into fixtures or finishes, or items built into the structure because of their sentimental value to the owner. Some of the most interesting features that I’ve seen include a large, built-in, indoor pool; a home where the corners of the foundation had intentionally been rounded, poured by using single-use concrete forms custom designed for the application, topped with brick; and an owner who removed flooring from a previous structure and installed it in the new structure (citing sentimental reasons), even though the flooring was of much lower quality than the rest of the structure.