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wood floors and moisture


sheree
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I need some advice/help please. I have hard Oak hard wood floors that were sanded, stained, etc after installation. There was no plastic or other moisture barrier installed first. I have cupping problems which seem to come and go in certain areas. A new A/C seeemed to help alot but did not resolve the cupping entirely. My house is on a conventional foundation and the land slopes down toward the house so rain water runs that way too. Underneath the foundation is appears to be dry. We put plastic down anyway. I did have some small roof leaks that have now been repaired but I doubt if that causes the moisture.

I am getting ready to put engineered wood down in another part of the house. Someone said it is hydrostatic pressure? Will engineered wood with a plastic layer underneath be the best choice? What about bamboo? Would moisture testing before laying the floor help? Thanks.

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Hi,

Did your flooring contractor bring that wood in, sticker it and then allow it to acclimate to your home for a few weeks before he started nailing it home? If not, it might be a while before things settle down and once the floor has finally reached equilibrium he'll need to sand it down again and refinish it.

How tight is the house? How well is the home ventilated? If it's shut up tight as a clam and you've got a family in there pumping more moisture into it, things will probably get worse before they get better.

ONE TEAM - ONE FIGHT!!!

Mike

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My guess is with Mike. No acclamation time. All wood floors including engineered wood floors require time to rest in the ROOM they will be installed in. This can take several weeks. Back when I was swinging a hammer full time, I once lost a flooring job because I wouldn't install it the next day. The lady was having a party on Saturday and wanted to impress her friends with her new floor. She called me on Wednesday and wanted it done Thursday and Friday. I said it couldn't happen because of the acclamation time, she said I'll find someone who will.

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Acclimation on the first question.

The engineered floor will have specific instructions for installation. Many times, the important stuff is in very fine print. Do not be surprised if the installer doesn't have a clue about installation instructions; many installers don't.

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The HW I have was left in the room to acclimate for about a week before installaion. I did not know that engineered HW must also stay there. I am shooting for an installation before Christmas so I don't have much time either. I plan to have the wood delivered by next week though.

I have a crawl space, not a full basement.

Do any of you know about adding dehumidifiers to your A/C? Do you think this will help? Someone told me there is a unit that can be installed that pulls moisture from the air in your house and below the conventional floor. This may be the way to go. Any other ideas about where the moisture is coming if the wood is ok?

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OK, crawlspace.....is there a vapor barrier? If not/probably not, that's likely the problem.

Moisture evaporates out of the earth, migrates up into the wood floor, the floor finish holds the vapor in the wood, and the flooring cups.

You need a vapor barrier most likely. After that, seal up vents and condition the crawlspace.

Dehumidifiers are essentially teeny tiny AC units; a refrigeration coil condenses water out of the air. Running your AC system will dehumidify the atmosphere reasonably well.

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Kurt has already mentioned the dual function of air conditioners which is something that a lot of homeowners aren't aware of. I'll add that there are quite a few conditions possible where the ac cools adequately but doesn't remove enough humidity. Also, some houses in hot/humid climates aren't sealed well enough for even a properly functioning AC to handle to humidity load.

Marc

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I need some advice/help please. I have hard Oak hard wood floors that were sanded, stained, etc after installation. There was no plastic or other moisture barrier installed first.

There shouldn't have been any plastic under the wood. That would have been a Bad Idea. A layer of rosin paper or 15# felt is the traditional paper used under hardwood floors but it's there to act as a slip sheet, not so much as a vapor barrier. It doesn't prevent cupping or crowning.

I have cupping problems which seem to come and go in certain areas.

Everyone says "cupping" when they might mean all sorts of distortion. Cupping is when each individual board curls in such a way that the edges are higher than the middle. Crowning is the opposite, when the middle is higher than the edges. Both create a washboard-like feel to the floor. I'd like to establish that you're really got cupping and not crowning.

A new A/C seeemed to help alot but did not resolve the cupping entirely.

What, exactly, did it do?

My house is on a conventional foundation and the land slopes down toward the house so rain water runs that way too.

That's a poor setup. Regrade your yard so that the soil slopes away from the house in all directions.

Underneath the foundation is appears to be dry. We put plastic down anyway.

Do you mean to say that you had a crawlspace with no vapor barrier over the soil? That's a Bad Thing. The soil "appeared" to be dry because all the water was evaporating into the crawlspace air. You should have put down 6-mil, black polyethylene plastic. It should now completely cover every square inch of the soil in the crawlspace with the seams, at minimum, broadly overlapped and with bricks placed along the edges and seams to hold it in place. If you did anything less, go back and do it right. Don't even bother to think about your floors for another minute until you've done this.

I did have some small roof leaks that have now been repaired but I doubt if that causes the moisture.

Yes, it's unlikely that they had any effect on the floor, unless the water was actually dripping onto the floor.

I am getting ready to put engineered wood down in another part of the house.

Follow the directions on the package as if your life depended on it.

Someone said it is hydrostatic pressure?

Hydrostatic pressure is the pressure that a liquid exerts against something. Lake Mead exerts hydrostatic pressure on Hoover Dam. The ocean exerts hydrostatic pressure on a boat hull. Sometimes ground water exerts hydrostatic pressure on a foundation. I doubt that anything is exerting hydrostatic pressure on your wood floors.

Will engineered wood with a plastic layer underneath be the best choice?

Best choice for what? What are the options? What are you're tastes? What kind of room is it? What defines "best"? Best looking, best performing, best price point?

What about bamboo?

It's *so* last decade.

Would moisture testing before laying the floor help? Thanks.

An installer should be monitoring the moisture content of any wood floor installation. It's essential.

If your hardwood floors are cupping, that means that the moisture content of the bottom side of the wood is greater than that of the upper side of the wood. This causes the underside of the wood to expand slightly, resulting in the distortion that we call cupping.

Most of the time, if the wood was acclimated properly before installation (and that's one heck of a big "if") cupping means that your crawlspace has gotten more damp since the floors were finished. I'd focus on the crawlspace.

Air conditioning dries out the interior of your house. As Kurt & Marc explained, a properly sized and properly working air conditioner is like a giant dehumidifieer. Dehumidifying the interior of your house will make cupping worse if the crawlspace below is damp.

Also, some cupping & crowning is normal with lower quality modern hardwood flooring. If your floor includes a lot of flat-sawn pieces, you *will* get distortion with minor changes in humidity. Better quality quarter sawn pieces won't cup nearly as much. Post a picture of the distorted areas and we can tell you if they're flat sawn or quarter sawn.

Also consider that you might be a super-picky whack job. Not that that's a bad thing. But some people see cupping where other people don't. I've had customers who were in tears about defects in their houses that *no one else on Earth* could see.

- Jim Katen, Oregon

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Do any of you know about adding dehumidifiers to your A/C?

You can not add a dehumidifier to the central air conditioner - just the act of running A/C will dehumidify the home. You can however put a dehumidifier in your crawlspace which will help with removing moisture. It will need a drain for the water it collects though or bucket brigade to empty the pan (not practical).

As mentioned by Kurt the problem is most likely moisture coming from the crawlspace - I would suspect that the crawlspace really should be surveyed/inspected.

As we can not long distant diagnose the problem (too many variables) perhaps calling a local ASHI home inspector would be prudent.

Look here: http://www.ashi.org/find/default.aspx for more information.

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If you are in Germantown TN (near Memphis) you have a great deal of clay in your soil; it retains water like a sponge.

My vote is moisture from the crawlspaces, either from groundwater or from condensation.

Is the subfloor insulated?

I have seen many homes in the South that have insulated sub floors and cupping wood floors. The insulation is holding water like a sponge and keeps the subfloor damp and this then makes the wood floors cup.

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Thanks so much everyone... Your advice has been very helpful. I will have someone look at the crawl space under the house since this seems like the most likely cause. There is no insulation under there that I am aware of but I am not/do not/will not crawl under there! [:-bigeyes.

Next, as an additional precaution, do you think it will help if I float the floor? Seems that it adds an additional moisture barrier to do that. Also, I am leaning toward a Hampton Hickory 5 in plank or a Bruce Townsville 5 in plank. On the Hickory the thickness is 9/16th and it doesn't say on the sample anything about the installation.

The Bruce have to find in 5 in. though. Also says glue or staple down. and is only 3/8th in thick. Other than for possible resanding at some point, is there any reason to get more thickness?

Is Oak better or Hickory? I have Oak now. Thanks again.

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  • 3 months later...

As a certified hardwood inspector with the NWFA I can tell you you need to do the following.

1. The grading must slope away from the house. If this is not feasible install a french drain. Imperative!

2. Get someone with the proper tools and knowledge to assess the crawl space, the subfloor and the hardwood for moisture content, humidity and temperature try http://www.woodflooringinspectors.com/ for an inspector near you.

3. Does the crawlspace have adequate vents to the outside and do they adhere to local building codes?

4. Definitely the ground should be covered by 6 mil black poly taped up the wall.

5. Every box of hardwood has the manufacturer's installation guidelines along with warranty and maintenance guidelines. Not adhering to these will void any warranty with the mfg.

6.Temperature and humidity levels must be between 60 degrees to 80 degrees f and 30% to 50% humidity levels excessive humidity will cause cupping.Even if unoccupied!!!

7. Acclimation not properly adhered to can cause permanent cupping which can only be fixed by a sand and finish IF the subfloor moisture content is less than 12%. And the subfloor and solid hardwood cannot have a difference of more than 4% for 2 1/4" or more than 2% for 3" or wider. If this occurs the cause must be determined before continuing. I cannot stress enough to follow manufacturer's guidelines. It distresses me to see what consumers are subjected to regarding nailing schedule, proper subfloor, proper spacing at the walls, inferior adhesive and general lack of installation knowledge by installers. If yours does not have a moisture meter find one that does or you will never know when it is proper to proceed.The installer will need one capable of testing concrete as well as the hardwood. Most only do one or the other.

8. Subfloor over concrete is always plywood cdx exposure 1. 1/2" by NWFA guidelines though most mfg require 3/4" and always adhere to mfg guidelines.

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I'm sure you mean humidity in the crawl? Excessive humidity in the home will cause crowning.

6.Temperature and humidity levels must be between 60 degrees to 80 degrees f and 30% to 50% humidity levels excessive humidity will cause cupping.Even if unoccupied!!!

Jim, yours is one of the most appropriate occupation/ surname relationships I've ever seen. Thanks for stopping by and thanks for taking the time to contribute.

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