Went to a BBQ at the house of some friends where I installed this product. I was shocked when I entered, to see the cupping that had occured. We have had a really wet year, and our hot weather has only just begun. The floor was on site 2 or more weeks to acclimate, HVAC was on and running prior to the install. When the moisture content got to within 4%, I installed it. My little pocket temp/RH device read 50% at the floor, and 44% up on the countertop. Subfloor moisture was reading the same as when I installed the floor. I used 15lb felt under the Jatoba, and for reasons I don't remember, the owners painted the subfloor prior to installing it ( WAAAY before)
So here are the questions...
1) I just recently read that plank should be within 2%, not 4%. True??
2)How much cupping is normal for a plank floor, assuming some is normal? Is it a measurable amount?
3) I suggested covering the crawl space with poly prior to the install, but the owner declined. The cupping doesn't bother him, but covering the crawl space now, will eliminate the cupping, correct? I pulled off a reducer I used at the door, and was surprised to see the same 3/8" gap I left at the time of the install. I thought I would see a reduction in expansion, but if it has, it isn't as much as I thought it would be.

If you don't glue and fasten, your suppose to screw and plug plank.

Ok, but isn't cupping normal in plank?

I think the truth should be told-5" of Brazilian Cherry should be discouraged in every way. It simply is not an appropriate floor covering. I have seen floors I installed, 3" BC, climate controlled, that look like crap. Complete failures from the standards I expect, yet we have guys all over the internet overselling the stuff(and other inappropriate exotics) and misquoting the NWFA stability chart to fool the consumer.
Anything over 4" should be screwed and plugged, but I wouldn't count on that holding Jatoba either. Not enough nails per sq in. I'm having a hard time with this glue thing under planks-eliminate the moisture barrier and hope the glue holds it down. Glued floors cup too. The people pushing this idea just need a way to push prefinished plank that can't be plugged. The only way would be to climate control the crawl space.
The only thing you can do at this point is cover the crawl space and make sure its properly vented on all sides. The wood may subside with some time, but you should expect massive, permanent cracks because the edge fibers have been crushed. Its good your customer doesn't care, this is why we don't hear more about this, consumers don't know any better.

My experience with jatoba has been as follows. I have installed thousands of sq.ft. of 3", finished in place. The ONLY job that had any signs of movement and cupping ( though not severe ) was a floor for a client that REFUSED to have a 6 mil polyethylene vapor barrier installed on the ground in the crawl space. Every other floor had the vapor barrier installed. The floors were layed over various subfloors, plywood and OSB, and 15 lb. asphalt felt was utilized as a vapor RETARDER (not barrier). Two of the floors mixed 3" and 5" planks and those floors have remained flat and stable for five years. All the floors were finished with three coats of OMU and one was stained prior to finishing. All the floors looked great and the customers are very pleased with their purchases. Some of the floors were verticle grain and others weren't. None of this seemed to play a factor in performance. All the floors were nailed ONLY with a Bostitch M111 FS and Senco finish nailer. This leads me to believe that most solid floors will cup if installed over a crawl space WITHOUT a vapor barrier, even if the space seems dry. And that 15 lb. asphalt is NOT a vapor barrier and does not protect the floor from moisture migration. I also installed 5000 sq.ft. of Carlisle Antique Heart Pine (8,10,12" widths) utilizing their installation method, which is either nail and glue (PL400 or Bostick's) or face nail into the joists with decorative nails. I chose the glue and nail method with PL400. That floor (after five years) still looks great, no cupping, no squeeks, no movement. NOFMA and the NWFA both recommend vapor barriers in crawl spaces when installing ANY solid wood floors. It has been my experience that to forgo this recommendation is to invite cupping of the floors. No glue, screws, plugs, or paper on top of the subfloor will substitute for this recommendation. One POSSIBLE exception are the newer vapor barrier products such as Bostick's MVP, Taylor's Lock Down, and Franklin's Titebond 531. These are newer advances in moisture control and could possibly eliminate the need for a crawl space vapor barrier. However, the problem with this concept is that you will trap moisture in the subfloor (similar to installing plastic on TOP of the subfloor) which could lead to premature subfloor rot and failure. The time tested procedures of keeping the crawl space dry and well vented, along with a poly vapor barrier, are still the preferred method of any solid wood installation over a crawl space.

Interesting:

Brazilian Cherry--

Dimensional Stability: Average (8.5; 1% more stable than Northern red oak).

http://www.woodfloors.org/consumer/whyT ... .aspx?id=2

Gary:
I'm being pushed more and more into floor installs along with my normal finishing.
I appreciated your input. It answered alot of questions I had on an upcoming job. And I do have the NWFA manuals.
Charlie

There is another 1400 feet or so of the same material upstairs, and it is nice and flat. I find it hard to believe, that gluing and nailing would have stopped the cupping. Not all the boards are cupped either. There are flat ones running throughout the house. The living room, which has the greatest height in the crawl space, is cupped the worse. It is also used the most. Could a swiffer wet jet cause, or contribute to the problem?

Disappointed in you Ken. You deliberately omitted the very next sentence from the NWFA website:

"However, actual installations have shown significant movement."

I see this a lot on internet sales sites. Many, but not all, internet sellers like to quote the NWFA stability chart, but fail to mention the lower paragraph warning of BCs pitfalls.

SK-moisture on the surface causes crowning.

Wet swiffer would not cause the cupping. Wood cups with either excessive moisture content or a RAPID increase in moisture content. I would look for water intrusion, plumbing leak or water sitting under the house. For cupping to be isolated suggests a local area problem within the home.

Isolated cupping....The entire living room / kitchen shows cupping. But there are boards here and there, singles, and in two's and three's that are flat, surrounded by cupping boards. I pulled the face off the d/w to check, nothing. The irrigation system is almost done, but hasn't run yet.

The house shares a little knoll with the GC that built the house. His is a little higher, a half acre over. This is gold country, lot's of clay, but the ground perc's enough for septic tanks, though this is on sewer.

The front of the house is on the high side of the lot, and is one step off the driveway.
The vents for the house are on the other three sides. They are to code, but must not be providing enough air flow. I'm going to go under there and take some readings, and see what is up.

Gary is right with the recommendation to cover the crawl space. The vents on only 3 walls is another factor. I see your in Cal, we had a lot of rain, plenty of floors cupped in the last El Nino of 97.
Mby big issue with BC is that its being pushed with decietful methods on unsuspecting consumers who have no clue about moisture, covering crawl spaces, nails-per-sq in, etc. Neither do many professional installers.

I base my own opinions by what I learned from apprenticing and selling exotics over-the-counter for the very guy who helped write the species guide Ken misquoted earlier. I'm right now seeing plenty of complaints from consumers who find the material difficult to live with, every footprint shows, every scratch shows, the wood is cupping, checking, splitting, finishers can't get water base down reliably, tongues split too easily during install, etc. And have you ever seen a BC-pusher mention the decimated rain forests? For these reasons and more, we routinely steered our customers to more reliable materials.

I saw somebody somewhere advise that the crawl space should be closed off and climate controlled with the house to make these difficult woods more reliable. The waste of resources that this involves is phenomonal, just so the consumer can have the "hardest" wood floor. Completely impractical and wasteful. There are other options if the customer needs a red wood, Merbau and Santos Mahogany will both be more reliable than BC.

The fact that Gary supposedly gets 100% success forever with BC does not make it a reliable product. As an installer, I want to advise my customers away from the problem woods, its part of my job. If they insist, they will sign every disclaimer imaginable. Reprehensible are the sellers who misquote copyrighted material and fail to advise the ignorant consumer of the possible, even probable, pitfalls they are about to discover the hard way.

I won't say it can't be done. I will say that few will truley succeed. As a professional, I need the populace to be happy and satisfied long term with their choices. This is doubly important with the rise of the DYI market. Anything short of that is a black eye on the industry and everybody who makes a living from it.

Marco, please clarify. What are you saying here? Thanks, I appreciate your integrity to our industry.

Don't jump the gun and assume. I had limited time and the phone was ringing. The link is there to investigate further. You'll find more objective and honest information on this site than anywhere else-- for an e-tailer. If there are things that aren't accurate or don't look right, let me know. Maintaining a 1300 page website isn't an easy task.



Please choose your words more carefully.

Thanks

The description is: The same material is upstairs and flat. Flat planks randomly throughout the house.
If the upstairs is flat, this would indicate the problem is not Relative Humidity within the home. Random areas flat may indicate the cut, being plain sawn or quarter sawn. Are the flat planks quarter sawn or plain sawn or various cuts?
The description given mirrors what we see in Bamboo flooring. Lack of PROPER ACCLIMATION is the main cause of cupping when subfloors are low in Moisture Content. The material is shipped in plastic to protect from humidity gains while in transit from China. Some of the B. Cherry seen is also wrapped in plastic for protection. Proper acclimation may require opening the boxes and removal of the plastic. Without removal of the plastic, the material will not acclimate to the local Relative Humidity.
Stack and stick is also required. Stacking in a room, next to the wall, does not allow for proper circulation around the material.
In Florida, acclimation failures are seen often due to the high RH.
This installation is in the "gold country" of the mountains and on the side of a hill. Water can be under the house during any part of construction??? The lower areas of the subfloor can be high in relative humidity with surface low in RH. Acclimation of the home brings the moisture upward with the lowering of RH in the home.
Cupping is always related to changes in Moisture Content. The effort is to find the reason for the change and who is responsible? Drying too fast can cause cupping as well.