Last time in Part 1 of this series I shared some basic info and many pics about the wood floor mystery where one half of a condo had cupped floors and the other half did not. The readers jumped right in with some great stuff in the comments (especially Douglas Volk), and here’s what we know so far:

- In the left side of the condo, the floors are cupped; the bottom of the flooring has a higher Moisture Content (MC) than the surface.

- The room temperature is a steady and comfortable 63–70 degree F average. Let’s just say, people and flooring should be comfortable.

- The humidity is average for this time of year (a little on the dry side). But the floors are cupping!

- The surface temperature of the flooring reads as low as 60.8 and as high as 73.2. (But where?)

- The vaulted ceilings on the right side of the condo are a factor.

- Air circulation is a factor.

- The foyer is noticeably different. A telling factor, but why? Remember that the flooring is buckled at the entry.

- The right and left sides of the tri-level condo have different construction designs: vaulted ... or not.

- The air circulation of the right and left halves is different.

- Left/right side temperature are a definite factor. Bingo!

- Blog commenter Doug Volk hit on some really solid points:

"You'd expect a higher level of MC ... left side ... dew point …" Doug is correct. There is higher MC in the flooring on the left. But the right side is … closer to the action? Here’s a hint: This has nothing to do with dew point. (You could argue it might be a factor, but that’s not much help here.)

"But, why would the MC be higher on the bottom of the boards (necessary for cupping) than the top?" And that, Doug, is where the anomaly comes in! That is the million-dollar question. You are now where I was when I looked hard at the third-level floors and ran down the stairs and out the front door.

“The right side floors were basically at grade, over crawl space, with no ceiling below, and no joist plenum to trap colder outside air.” And again, the floors closest were flat and even!

“Additionally, the crawl space air, being exposed to a relatively constant ground temperature (and assuming an adequate vapor barrier) might help mitigate …” Nope, you have the answer already, no need for assumptions. You got this. Never ASS/U/ME anything.

Finally, the general construction and design are definite factors.

Thank you, readers. Let me expose some clues for you before we wrap this up soon in Part 3 of “The Half-Cupped Floors.” Here are some clues:

The book graphic with my goofy face has several photos—all are clues.

The introduction regarding Dr. Cooper has several clues. Consider: “earth science, physics, chemistry and math,” “advanced education.”

” …New England village at the base of sprawling mountains and rolling hills,” “…over a crawl space” and “vaulted ceilings.”

There are also clues in here: “PS: On November 24, 1971, Dr. Cooper was not yet born, but Cooper was involved in an unsolved mystery involving hundreds of thousands of dollars in stolen money that was never found, at least not completely. Cooper could offer at least two initial components to our flooring puzzle. That would at least get you halfway there, mathematically speaking. The details will unfold before you like a Swiss Army knife if your approach is principled enough. Draft what conclusions you can from the material provided and be cautious not to air out lofty conclusions. Send me questions and if it gets frustrating feel free to vent, I can take it. Please play nice with the other floor guys … we are professionals.”

And, finally, notes from me upon inspection of the tri-level:

The crawl space was a cold, nasty, scary place. Here are some relevant photos:

All materials including flooring, fasteners, abrasives, stain, finishes and equipment more than acceptable.

The tape measure photo shows, with all the site conditions, that the installation was spot on: 65 inches in 20 rows: 3.25 x 20 = 65 inches. FYI 10 rows consistently measured 32.5 inches.

There WAS other work being done in the condo on ALL levels.

Let me ask you:

The flooring contractor needed to prove that his installation and finishing was not the cause of this cupping complaint. Does his case hold water here?


Stephen Diggins works for Wood Pro Inc. in their Salem, N.H., branch as manager and training director. He has many years of installation, sanding, finishing, gymnasium design and technical consulting experience, which he uses to assist his flooring customers on a regular basis. With almost 30 years in the flooring industry, he has been a freelance columnist for magazine, newsprint and online medias and has conducted product seminars ranging from wood flooring to luxury vinyl tile.