Replies

1. 
   Rich_Watkins | Dec 18, 2001 02:02am | #1

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   Most floors shrink because of too high a moisture content when installed and dry out after installation (and contract). Your floor did the opposite and is not uncommon. Red Oak is highly susceptable to movement caused by changes in relative humidity. This flooring was either very, very dry prior, and/or a lot of humidity was added to the house (did painters come in and spray the walls after the floor was laid down? Do you have a humidifier on your furnace?) or was nailed tight to the walls. If there was an expansion zone allowed around the floor then sanding the floors 'flat' should work. Be prepared for a mess. If you're not sure about an expansion zone ask your installer and then pop some base and shoe off in a few different areas and check. Cost for a thorough sand and finish would be about $2.50 a sq. ft. in my area N.W. PA. Good Luck. Rich

1. 
   IanDGilham_ | Dec 18, 2001 02:55am | #2

   *Jon,The fact that the boards are cupping suggests to me that moisture is coming from below into the boards.What is the sub-structure? -- if it is crawl-space, is the soil wet? -- is it ventilated?It is better to cure the cupping before re-sanding so try and find out the source of the moisture and cure that first.I doubt that it is an acclimatisation problem with that amount of movement.

1. 
   David_Taylor | Dec 18, 2001 05:02am | #3

   *Jon,What type of climate do you live in?Do you have a full basement?Is there an expansion joint along the perimeter of the flooring?How long ago was the flooring laid?David

1. 
   Jon_Mochizuki | Dec 18, 2001 06:39pm | #4

   *Some particulars: Floor was installed in late May. There may have been some moisture below, since I believe it rained in April (see below). I noticed the cupping in September. Painters came in November.The floor is on post and beams with a crawlspace below. The space at one time was flooded with rainwater. (A drainage system and sump was installed around the perimeter of the foundation in June to prevent any water from getting under the house again. It's rained recently, and it is dry under the house now.) I'm in Southern California.The problem was prevalent before painters came in. It happened maybe a month or two after the floor was installed. I've thought about this - would a combination of not properly acclimating the wood and finishing it quickly cause the problem? As I mentioned, I don't think the wood was allowed hardly any time to acclimate and it may have been a little moist in the house. It was installed and varnished in a couple of days. Since the bottom of the planks are unfinished, could moisture cause the bottom to swell and since it was varnished, the tops would remain sealed and dry?Also, I should mention that it was threaded into an existing wood floor - same material and it is fine. The only portion cupped is the new. In my view, if it was moisture from the crawlspace, the whole floor would have cupped. I suspect that maybe Rich is correct in that the wood was very, very dry when installed. The floor had space all around and was not nailed tight to the walls.

1. 
   George_W._Carpenter | Dec 18, 2001 06:50pm | #5

   *Jon, if your house was wet, and the material dry... acclimation would have lessened the post-install expansion. However, come dry-season... you'd have picket-fence gaps between the boards, and would be asking about fillers.Sounds like there may be some high RH still in the crawlspace or subflooring.How many bad boards are there? It's possible to rip-cut the existing cupped boards out (few?) and to rip the bottom of the groove off and fit new boards in. Not easy, just possible.I'd start with getting your floor technician or General Contractor back in... and ask them "whattayagonnado?"-GWC

2. 
   Rich_Watkins | Dec 18, 2001 09:32pm | #6

   *Jon, I think Ian is correct in his theory about moisture coming from below. The floor was installed in late May, water drain installed in June, Cupping became noticable in September...Bingo. Moisture migration is insidious, it happens over a period of time, not right away. Maybe sanding the floors and waiting a month to see if the cupping stops would be the course now. Then have the floors disced and finished if it seems that the moisture has stopped. Might not be a bad idea to check the moisture content of the joists and sub floor from the crawl space.

3. 
   jim_l | Dec 18, 2001 10:35pm | #7

   *Jon, since you say the original flooring is fine, I have to think the new stuff had a higher moisture content when installed than it should have. The top surface dried and the bottom surface didn't (Was it installed over a moisture barrier?). I've posted this before in response to a problem. You need to be guaranteed, by your supplier, an 8% or less moisture content or you'll have problems, because the standard thought of a couple of weeks acclimation is nowhere near enough. Oak flooring will take up to 3 months to acclimate if it's too wet. Flooring should simply be put down dry and well sealed.Also, I don't believe you mentioned the face width or wether it's quartered or just mill run. Quarter sawn flooring gives you a lot more latitude for moisture variables because it only moves 1/3 as much as flat sawnJMHOpinion.jim l

4. 
   Jon_Mochizuki | Dec 18, 2001 10:59pm | #8

   *I think the boards are 1-3/4-inch wide (?) There is no moisture barrier underneath.Is it safe to assume that given the fact that it was installed in May, the floor has acclimated and that cupping will cease?My contractor has already started to correct the problem by replacing the crushed boards and plans to sand and refinish.Again, it seems to me to just be an acclimation problem since the old redwood is fine.Thanks all for the advice.

5. 
   Luka_ | Dec 19, 2001 05:07am | #9

   *Jon,Why did you lay the new floor ?

6. 
   Jon_Mochizuki | Dec 19, 2001 10:03pm | #10

   *A flooring contractor laid the new floor. It is an extension of a room that already had hardwood flooring in it.The old floor had no vapor barrier - I suppose I can add one underneath the floor framing, but the old floor is fine.

7. 
   jim_l | Dec 20, 2001 12:08am | #11

   *Jon,I reread your original post and had missed the crushed part. If the floor swelled after being laid, it's obvious that the flooring absorbed a lot of moisture from below after it was laid. Was new crawl space added for the room extension?Acclimation isn't what you needed. The crawl space is too wet.

8. 
   Luka_ | Dec 20, 2001 01:23am | #12

   *Your old floor is 'fine' because it has been there for years. It has done it's shrinking and swelling, and being sanded, etc. It is 'acclimated' to the existing conditions. ie, the crawl space may 'feel' dry to you, but it is still adding moisture like mad to the wood of the house. The existing floor reflected that condition. It is/was full of water. Especialy just before the new floor was laid.Put bone dry wood directly on top of relatively 'wet' wood, and the wet is going to migrate quickly into the bottom of the dry wood, Swelling the bottom, while the top doesn't swell as fast. Cupping. No mystery. You should have had a moisture barrier under the new flooring. Better than that, you should have done what you still need to do. Vent that crawlspace mechanicaly for a while. (Fans) Make absolutley sure that no more water can make it's way under there again. (I am nowhere near convinced that you have taken adequate measures there.) Once it is actualy dry, and not seemingly dry, put down a couple layers of thick poly, and cover with pea gravel. Once the structure itself, and the orignal flooring is bone dry, then would have been the time to lay the new floor. Even then, it would not have hurt to put down a run of #30 tarpaper first.Almost makes me wonder if it would be best to take up the new floor and start over again.

9. 
   Greg_Warren | Dec 20, 2001 06:10am | #13

   *Check the moisture % of the old floor, and see if the new has the same %. You cannot refinish the floors until the moisture % has declined back down to 7-8.5% moisture. To do so before that happens will create crowning of the new floor when it does dry out. That look occurs because the entire board is now cupped. If you sand now, the drum sander will take off the high edges on the sides of the boards. When the boards lay out somewhat flat after drying, those sanded side edges will now be lower than the middle of the boards. Crowning is just as unattractive as cupping. You will need to sand again. Your general contractor and flooring contractor are doing you a disservice by performing any fixes at this time. It takes two months for a floor to lay out flat once no more water is introduced. I don't think that has happened yet. Check the moisture % of the subfloor under your new wood floor. If its moisture level is more than 4% higher than the finished floor, your floor will stay cupped to the degree that that level increases over 4% and higher. You can bet that the subfloor is your problem and the underlying issues that surround that. It is rare that the finished floor needs acclimation when it is 2 1/4 wide and less. It has probably been parked in your locale for some time anyway, since your distributor was most likely buying 20K sq. ft. and more per delivery. You will just have to wait until everything dries out before you refinish. There is an element of risk when one buys a solid wood floor. If your flooring contractor was aware that the crawl space was recently flooded, he should have checked the moisture content of the subfloor and the joists from underneath before proceeding with the installation. Even then, a tear out is not in order. You just got some bad luck with the contractor draw. Maybe the GC pushed him into installing it knowing full well the situation just to get your home completed. That happens. It is up to the sub to say no. GW

2. 
   Jon_Mochizuki | Dec 20, 2001 06:13am | #14

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   My new red oak hardwood floor is cupping very badly. In one area it appears that the floor has swelled so much that it has crushed one section of plank. I believe it was due to the fact that the wood did not adequately acclimate to the house moisture content. I think the new wood was left in the house for less than a week, but I don't really remember. What can be done to remedy this without totally removing and replacing? Can sanding fix this? All my new cabinetry is in and I do not want to replace the flooring.