A friend had oak hardwood flooring installed 2 years ago. It is 2-1/2″ width x 3/4″ thick.
The family room is over a vented crawl space. The hardwood has roofing paper under it, probably 15 lb.
Now that the humid weather is here, the strips are cupping up. The house has central air. The floor will uncup again in October.
Apparently, the crawl is pretty damp. Anybody else run into this?
I’ve had a house with a very damp/ wet crawl that didn’t have problems with its hardwood floors.
Putting a fan in the crawl is about the only thing I can think of.
Thanks all.
Replies
Venting crawl spaces is a bad idea. They are relatively cool, so warm moist air enters the vents and moisture condenses in there--making for a rather damp environment.
Close the vents, put a vapor barrier over the soil, and if possible, condition the space (heat in winter & A/C in summer.
"Venting crawl spaces is a bad idea."
Gotta love these simplistic, absolute statements! You're right - in some parts of the world, like where you live, it IS bad. In other areas it's best practice and the problems occur with inadequate venting.
Sounds like the OP lives in one of those places where it's not recommended, based on the summer humidity/AC comment. Just had to bust your chops - nothing personal :-)
seems to me that your area has soem high humidity that should not be vented into the crawl also.
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On the coast you may be right, though I have friends in Half Moon Bay a few hundred yards from the coast, and all the homes there are vented. I suspect that one of the keys is that there is typically very little variation in moisture inside and out, and not a lot of variation between seasons. Just guessing...
OK, venting crawl spaces is a probably a bad idea if you live where the ground temperature in the crawl space is at or below the dew point much of the time--with relativley warm humid air outside. Under those conditions, ventilation is pumping moisture into the building.I think that would include most of the Midwestern, Mid-Atlantic, & Southern States, and parts of the Pacfic Northwest and New England.Maybe it doesn't matter much in the Southwest and Inter-Mountain West.Including crawl spaces in the building envelope (vapor barrier, insulation, conditioned air) is usually better than ventilating the space IMO.
Here in NY, the building code requires ventilation of crawl spaces, and bi's are really annoying about making sure it's done.
Don K.
EJG Homes Renovations - New Construction - Rentals
Tell them that it is not crawlspace, but a basement for midgets.
Here I'm required to put a vapor barrier on the inside of below-grade framing or firring, on the inside masonry basement walls. This of course traps moisture in the wood which then grows mold and rots.Nevermind that some of these basement remodel projects are being done to remove and replace the original stuff that is moldy and rotten due to this vapor barrier requirement.I play along--then tear the vapor barrier down after the inspection is over.
Here's a blanket statement for you.
Venting crawlspaces is a bad idea anywhere, anytime, period. There is no situation where venting a crawlspace is a best practice. I will be happy to respond to any example that you can name. It's nothing personal, I just can't sit quietly while one of the worst myths in construction is perpetuated.
there ya go!
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Eggs Akley! I need a dump truck, baby, to unload my head
You won't pass inspection in my locale if you don't have vents in your crawl space.edit: I see DonK already responded, same area.
Edited 7/3/2006 12:09 pm ET by TGNY
Used to be like that here, and even the inspectors would tell you seal them up as soon as they left<G>...we are now allowed to have unvented conditioned crawlspaces...a big deal here in the land of 100% humidity. I need a dump truck, baby, to unload my head
WHat' the best method for conditioning?
All the girlies say that I'm really kind of fly for a white guy.
I'm running a slotted perimeter drain inside the foundation, 6 mil plastic up the walls some, and then 2" foam on walls. Foam has to stop 2" from the top for termite inspections.As soon as the house is dryed in, I put a dehumidifier in the crawl. If it works well, it comes out when everything drys out... a variation is to pour a rat slab, if the crawl is going to be used for storage.In a regular vented crawl, we have problems here with the duct work "raining" when the ac is on. Several reasons it happens, but sealing the vents, getting in a continuous vapor barrior on the floor, and running a dehumidified gives pretty good results...I'm sure there's a Brazillion other ways<G> I need a dump truck, baby, to unload my head
I got to save that. That's my exact conditions. I think my vents are closed I got to check. The barrier and dehumidifier are definatley going down by end of summer. My house was built in the late sixties. No ground barrier, or insulation in the crawl. My duct work isn't wrapped either.
All the girlies say that I'm really kind of fly for a white guy.
Fan will be fine
if it is part of a dehumidification system along with vapour seal to keep the moisture down
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I'm assuming the cupping is very slight and noticable where the sunshine reflects off the floor.
The humidity in the air may cause the upper side of the groove to expand and give the floor an appearance of cupping. Actual cupping would require both edges of of the board to lift. Another explanation could be seasonal expansion. All hardwood expands across its width especially in humid climates every summer. Expansion causes pressure across the floor and the grooves ride on to the tongues of the hardwood, again giving the apearance of cupping.
I have seen cupping in plank and wide board flooring in areas of uncontrolled humidity but seasonal cupping in 2½" oak seems unlikely.
The crawl space and the flooring may be unrelated problems.
May neighbors respect You, and troubles neglect You.
Gord
What you describe is a humping center of the boards, not cuppingwhat he has is very common over wet crawls, it is because the finish on the top side prevents or slows moistrue entering the wood fronm the top. But with hydrostatic pressure from excessively damp crawl spaces, the unfinished bottoms of the boards absorb more moisture faster and expand. That makes both edges of the board rise, because the bottom is now wider than the top.I've seen it a dozen times and always in connection with damp crawl spaces. One house where my wife cleans is a good demonstration. It rambles around and has 3-4 different kinds of foundation from basement to deep crawl, to an 18" slide crawl. One area has sealed slab, anohter has plastic under stone with a dehumidifier, and the low one has almost nothing to control moisture. That is the area that sufferes the worst.
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I don't have enough information to make an accurate assessment. Moisture readings of the sub-floor, hardwood and the brand of pre-finished might be of some help.
Without more information, this is a guessing game. I'm throwing out possible scenarios not solutions.May neighbors respect You, and troubles neglect You.
Gord
Good, well reasoned answer.
Made me wonder: Would finishing both sides of the flooring (much like back priming new siding going up on the outside of the house) be a worthwhile idea or an enormous waste of time and effort? I know, finishing the back side would have to be done as a separate effort prior to installing the flooring while finishing the top of the flooring would have to await its installation before being undertaken. Seems like a lot of work right from the beginning of the idea, no?
But, would there be any benefit to it?Griff
Many of the imported pre-finished hardwoods are commonly finished on all sides. Possibly an attempt to maintain the boards integrity when shipped from South America to different climates. There may be, but I have not seen, examples of cupping in floors finished this way, even in the wide 4" plus widths. Of course most of these woods are extremely dense in comparison to oak and even maple.
Seasonal expansion is a controlled problem in woods common to North America. Flooring is designed to move without showing ill effects. Some woods have more stability than others, but they all move. Stability isn't necessarily related to hardness, Maple is one of the hardest indigenous examples, but maple isn't a very stable wood. I'm not sure what would happen if both sides of common varieties were finished. We back prime all sorts of woods when using them in damp or exterior locations but none of them are expected to look, perform or cover such a massive area as hardwood flooring.
The initial discussion about hardwood has also evolved into a debate about controlling a crawl space environment. There are some excellent points raised. Whether cupping is a result of condensation on the tarpaper caused by the air-conditioning or an expansion issue, laying hardwood over a crawlspace is probably not a good idea. Seasonal abnormalities might be something the homeowners are better off learning to live with.May neighbors respect You, and troubles neglect You.
Gord
Are you trying to tease us?
secret decoder ring necessary to make that small print visible enough to read?
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I couldn't shrink font with board tools twixt cut and paste from MW after connection blip.
You know the last person who accused me of being a tease was a deliciously enticing older woman who had a little too much to drink...
LOL
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Side note: Is the fine print to flush out the younger women who don't need bifocals? LOL!
Seems like I've heard the drinking and/or older or unattractive women are more attractive with the booze. Not being a soccer fan, the radio had a thing on about beer helped lump watching soccer and picking up older women in the same group - the beer makes it better. They said German beer was almost tapped out, partly due to the 70,000 Englishmen flooding in. Seems like the daily consumption was 17.5 pints per person! Plus the tree in the square was dying...! I can't imagine why... For me, golf and fishing are an excuse for alcohol consumption and if you're lucky you can brag. I've been the golf cart beverage wench on golf outings many time and I enjoyed the outdoor distraction from the office when I could imbibe a little, but then I'm not into sports unless my team is in a last play off, The first five mintutes and the last five are what counts to me. And, watching a whole game, dressing the dog in team colors, only causes us to lose. Go figure...I'm a girl who isn't into sports.
I'll stay out of watching sports as we are obviously jinks! Just a little humor and not to hijack this serious thread. Enjoy your sports, embrace them! Just had to tease you Gordsco. Have fun and enjoy yourself (hopefully, not literally!)
To be serious, I'd still do the indoor humidity tests first. They are cheap and the answer evolves. Then, I'd do the moisture test with a meter. If still too high, it would likely be the crawl. I don't know diddly about the moisture in a crawl other than the childhood experience I mentioned. As a kid I went under there to hide, most likely. It was wet and gross, but did not cause problems in the flooring in the ranch home circa 1960 in Knoxville, TN. Based on other's, it seems like the underlayment might not be ideal in the situation.
Close the windows and run the A/C - cool! Also a dehumidifier, if needed beyond a week or two of the A/C. If that doesn't settle the floor, I'd look at a vapor-barrier in the crawl space. but FIRST remove a small section of quarter round and see if the recommended expansion space has been left. Most manufacturers require either 1/2" or 3/4", to allow for expansion due to humidity. If the expansion space is inadequate, that could very well account for the summer problem. If that is the case, rely upon a seasoned/veteran installer here for advice on a correction. I suspect it could be trimmed to allow for the expansion. Just remember, it will shrink in the winter and you don't want gaps between the floor and the molding in the winter.
Based on the underlayment you mention, I'd check the above ground options first as this sounds more like relative humidity rather than the crawl, while that is a possibility. I'd try the easier methods first. If they don't work, I'd be looking at the crawl space. Good luck.
P.S. I've never heard of roofing paper as a moisture barrier for wood floors. I'm relatively sure this is not recommended by a manufacturer of wood flooring. A cheap vinyl/urethane? flooring is the strongest I've heard of, other than the usual recommended moisture barriers. If it works, that's a new one on me, but it doesn't seem to be doing the job if the moisture is from the crawl.
I appreciate all the responses. Good to know others have seen this. It's a new one for me.
As far as the roofing paper under hardwood, that's all I've seen anyone use under hardwood here in Cent. KY. For laminate flooring, there's usually a manufacturer's product they sell with it, but under 3/4" solid hardwood it's 15lb. felt.
What other products are being used?
Karl
red resin paper aka builder's paper
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Where at in Central Ky? I'm just South of Louisville
One other thng to check is that the quarter round isn't nailed to the floor. The
at kills the natural expansion and contraction of the wood.
All the girlies say that I'm really kind of fly for a white guy.
The dehumidifier is needed in the crawl qwhere the source of moisture is.Tarpaper is acommon underlay for wood floors especially when laid over damp crawlspaces, as an attemp[t to slow the migration of moisture into the back side of the wood.
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"Then cover subfloor with a good grade
of 15 lb. asphalt felt/building paper, lapped 2"-4" along
the edge seams. This helps keep out dust, retards moisture
movement from below, and helps prevent squeaks
in dry seasons."From NOFMA and WFI.https://www.nofma.org/Portals/0/Publications/NOFMA%20Installing%20Hardwood%20Floors.pdf
Thank you, Bill, for the additional new info. In 15 years, I never heard of this. It is quite possible this method was used and resulted in no claims. Bottom line, I'd go with the manufacturer's recommendation to preserve the warranty on a significant purchase. Of course the manufacturer is requiring what the know to work in a warranty. Of course, there are other good methods that work based on experience. I'm pro-warranty , as a consumer, in that I want to have the benefit of it. If I had repeated good experience, otherwise, I'd probably give it a shot myself.
I'll have to look again at the original post, but it seems like it was strip flooring in question. My second story older house has that. In the uncarpeted areas, there has not been a problem in 22 years, but it is not on grade and the humidity is constant throughout the year in my home. Without the dimentional stability of multi-ply products, and not knowing the product, I'm still inclined toward relative humidity, personally, in the initial poster's issue. I grew up in a house like that and don't remember a problem with the damp crawl. While NOFMA has info on this technique, if the warranty is of concern to the homeowner whi whom has specific recommendation, it would be a fight with the manufacturer if outside the recommendations. If one has confidence in a different technique that seems to work well, and is less concerned with the warranty issue, it sounds do-able Experienced folks know what works AND the manufacturer is in C.Y.A. mode. Thank you, very much, for the additional information you bring to us. It is valuable and most welcomed. Thank you.
http://www.br111.com/pdf/34Solid_Install.pdfMoisture content in subfloors should be less than 12% with the difference between sub and hardwood less than 4%. A moisture barrier may be required as asphalt paper is not considered a vapor barrier.The first principle is that you must not fool yourself and you are the easiest person to fool.
Richard P. Feynman
Edited 7/4/2006 7:36 pm ET by CJM
In my area red rosin paper is usually installed over the subfloor before hardwood flooring. I have seen felt paper used for the same purpose, not often though.I imagine that 30 lb felt paper would be an excellent vapor barrier for subfloors over a crawl space.
mike
Felt paper is not a vapor barrier. It will freely pass water vapor. The plywood will slow down vapor more than felt paper will by an order of magnitude. Let's try to put this myth to bed as well. A water molecule 1/1,000,000,000th of a foot wide. It will pass quite easily through most building materials. There are vapor barriers out there, but just because a material is a barrier to water doesn't mean it is a barrier to water vapor.
Mike,
I am am a stickler for the manufacturer's recommendation as I've seen too many claims denied for failure to follow them in the business. However, the moisture readings someone suggested and humidity levels (the manufacturer's have that too), are a great place to start, preferable prior to installation. Not to mention the recommended acclimation period they recommend prior to installation.
Again, I'd still check the expansion space under the trim and run the a/c first. That is way easier to determine if it is relative humidity or from the crawl. I do not remember which, but the optional vinyl or urethane cheapest flooring was the suggested option, but I'm not sure this was a manufacturer's recommendation or a "work-around". If the moisture was not checked prior to installation and factored then, if could be either case. If it was checked, a vapor barrier in the crawl might be the way to go, along with the fan. Good gutters and perhaps a french drain deal might help the crawl moisture. But, I'd do the easy, cheap, easy things first to be sure.
Again, I am well aware that the manufacturers recommend what they think will work fine, so that is what is warranted - they seem to go with one tried and true method. That doesn't mean other techniques are not effective. I know other good options likely exist and are proven by experince, but not covered by warranty. If the warranty is of any concern, I'd go the safe route. If one is a risk-taker, try those proven alternate methods, at risk of the warranty. I don't want to see this floor as a tear out, and it shouldn't have to happen. I do think using the relative humidity tests would help prevent that. If they don't provide the answer, then the crawl must be addressed. Since this seems to happen in the summer, I'm still on the "relative humidity" checking theory. Since the crawl is likely damp year-round, depending on rain/snow, it would not be my first suspect. But, it could well be the problem. Only testing will tell and I'm cheap and patient, so I'd personally be inclined to do the easy stuff first, before spending money without being sure.
As I mentioned, Mammaw's house had the damp crawl, but no problems with the wood flooring. Since everyone is deceased that could tell me about it, I can only say that I remember them opening the vents in summer and closing them in winter. I have no clue what that means overall. That is just what they did and can't recommend this either way. I have on-grade slab construction, so no personal experience with a crawl space as a homeowner. As a kid there was finally one wall mounted a/c unit. It WAS always damp under the crawl in the summer - I was in there hiding for fun and play. Construction of this home was about 1960 in Zone 6, Knoxville, TN.
If you use an alternate method for a customer, which is not in keeping with the warranty, and there could be a problem. It can become an installation problem and no one wants that headache. If it is one's own home, try what you know to be successful if you are less conservative about the warranty issue. Otherwise, I recommend the manufacturer's recommendation for the installer's protection against future claims that are not warrented by the manufacturer. If that is not a concern, as one is on their own.
I'll stop contributing to this thread as I keep saying the same thing. I just want installter to cover their tail by following the recommendations, installing strictly following their recommendations and to prevent warranty issue that can bite you. If you are willing to assume the risk because you have a great alternative that works, take the chance if you are willing to assume the risk. Their may be great alternatives that are proven. If you are willing to go there, it might be a good situation. Good luck to the original poster on this topic.
I've seen this in a neighbor's house who had just spent $$$ on a remodel, leaving only the foundation and building back up. All of her floors cupped. I believe she has/had moisture problems in her crawlspace- I'm not sure of the origin.
As we prepared to put down some new flooring for our remodel, I was very conscious of moisture problems. I found a free NOFMA article that was informative: