We had 5" width 3/4" thick Somerset prefinished flooring installed in our new house, severe cupping, > 1/8", has occurred throughout the wood flooring (approximately 1200 ft2). I contracted a certified wood flooring inspector and his report stated that prior to installation the installer measured the moisture of the subfloor and wood and stated it was within 2% (but no absolute readings were provided). Moisture measurements taken in early September were:

Subfloor 9.6%
Wood Floor 7.1%
basement joists 13%

The inspectors report gave the impression that the moisture was from the concrete basement and suggested installing a dehumifier to determine if excessive moisture is being removed from the house atmosphere.

My question is does this recommendation seem to make sense given that there are not indications with problems with excessive moisture in any of the finished basement flooring which is carpet, carpet tiles, and glued vinyl tiles?

Should the dehumidifier be installed in the basement or the area with the wood flooring?

Some comments from the report are copied below.


The installed wood floor is cupping in all installed rooms. The cupping is rated as severe because of the 1/8" measurement on the cupping

The outside gradient is sloping away from the foundation, and all of the gutters are connected to downspouts that lead moisture away from the foundation.

The finished basement does not have a musty smell, and no water marks were detected on any of the walls. There is adequate ventilation in the basement, and the HVAC is operating at normal living conditions.

wood planks need a balanced m/c. the wood is expanding on the bottom or shrinking on the top one or the other thats what causing the cup. You need a moisture meter and a hydrometer. the readings on the top oft he floor have to be within two percent of whats underneth ie your subfloor. The dehu needs to go in the basement but chances are thats not going to help that much. YOu say its a new house was the hvac up and running before the floor went down? My guess would be that the floor was installed over a subfloor that was a little too high mc. the floor pulled the moisture out and swelled it up now you have the result of a rush job installed by a guy who doesnt know how to use a meter. Id bet 10.00 bucks that they dont even own one to begin with (a meter that is). Sorry to jump to conclusions but if he would have checked it we wouldnt be talking about it here.

What does "adequate ventilation in the basement" mean? Did the inspector provide any numbers for temp and rh vs the temp and rh upstairs? Did he do any pin meter tests and provide numbers for that?

RH when flooring inspector was at house was 53 to 55%, temperature was about 65 (it was a dry sunny day in Indiana) we live just north of Indianapolis, heating and A/C are from geo thermal system we have approximately 750 feet of plastic pipe in the back yard. HVAC was on at least 10 weeks before flooring was delivered to new home - temperature was maintained at 65 F 24 hours a day all through Sept, Oct and Nov 2010. When we moved in winter temperature was maintained at 68 to 72 F all day, during summer we kept the house at a constant 72 F all day and night, circulating fan for HVAC is on all the time to filter the air. Flooring was installed in mid November 2010. Cupping started to appear in February 2011 and it took months to get flooring contractor and flooring representative to come look at the mess the floor is in.

Kevin,

you really shouldn't make remarks like that..i know you want to look like Capt Do Good Hero floor avenger, but look at the facts the HO provided.. temps, conditions, humidity, timelines..
even if the sub-floor was a little wet..3 months is more than sufficient to dry a subfloor that got rained on during Irene..

The guy went as far as to record and document readings in his paperwork..it suggests something..He's not a hack.

plank floors and environmental condition can be very difficult to negotiate as to source of problem..
water and moisture in general are.

Now, hes the fact I see..The HO points out the the installers reading s were this and that, but no real recoireded numbers can be given, however, he is in fact doing the same ting..he says house was kept this temp for this periods,at this RH level..
and during this time, the house was this, at that, for this long.

Ok..now who telling the truth.. The HO has all this info, but a pro protecting his work does not?

how many HO's you know who document all this info? or even know what to look for and check?

the manufacturer will never own it..( and I know somerset very well. installed thousands of SF of it form plank to strip.\)
are they flawless?..hell I dunno..doubt it..

So it took 3 months or so to start cupping? Hmmm

Cupping started soon after we moved in, end of Dec 2010. By the end of January the cupping was evident throughout the house, there are very few boards that not cupped. It took three months to get the company we bought the flooring from, the installer and the Somerset rep to look at the floor and write their respective reports.

All parties agree that there is a problem with moisture but do not know what the cause is. My conclusion is that no one wants to take responsibility

Thats not what you said, you stated originally it started in Feb, not December. Get your facts straight.

I also noted the contradiction of cupping timeline. If it was 1 month or 3 months, either indicates to me that the floor was ok for at least 1 month. I've generally seen floors cup in less than a week if an installer didn't put in spacer rows . it's possible that the installer did things properly . it's hard for me to say though.

I installed a floor over the summer near the ocean and it was perfectly flat for about 3 weeks until the homeowner turned on their AC . The AC dried out the kitchen and the basement was super damp. Then the floor cupped right away.

Thanks for your comments on the cupping, the cupping became severe somewhere between 8 to 10 weeks after moving in, but we first noticed the appearance of cupping within a month of moving in.

My question at this time is will a dehumidifier releive the stress in the wood - if it will where should the dehumidifier be placed in the basement or rooms with the flooring?

Thanks again for your comments

moisture imbalance. your answer is in the first post. wetter below than above. PUt the dehu in the basement and hope for the best. I would also consider putting the hvac on auto, running all the time is going to drop the r/h upstairs even more. You need to try and keep the temp and r/h in the basement the same as it is upstairs if at all possible.

What part of the nation are you in(state)

he is Indiana its in the first post. ANyway I never really responded to Trd's response and now I got a second so here goes. Ive been involved in the Hardwood flooring buisness for over 25yrs myself and my father who taught me much of what I know has been in the trade for over 40. In that time my family has done everything. My family has owned and operated a flooring mill, my two brothers are two of the best flooring mechanics in the trade, I own and operate a distributorship for the last 12 years the list goes on. Anyway I was doing inspections before nwfa was certifying people christ, I was asked to help review the current nwfa inspectors test before it was even offered to the public to make sure their wasnt any errors.
Now here is the plain old facts that I have been a personal witness. Most flooring installers dont end up buying a meter until they have a major problem. Of the 200 plus contractors who regularly but supplies here Id say about 20 have a meter and use it on every job. there are more guys that have them but they only time they get pulled out of the truck is after they have a problem then they want to tuck tail and blame it on the wood. Its not the wood fault.

Kevin,

thats a hell of a pedigree....
now heres what i said..you shouldn't make those statements because they are presumptuous and assumptions at best.

You odnt know the guy.

he did provide readings.

no one said it was the wood.
I don't believe it was.

what i believe is the HO did not give the full details..his details were TOO perfect.
and if they were true..the floor would not be cupped.

there was a moisture change or exposure after the fact..which is NOT the installers fault.

I have been doing floors now just about 20 years myself.
I learned for some of the hardest and knowledgeable men to work around.
that said,i don't disagree with your latter statements.. however, i would not be so bold as to jump in singing
about a man I don't know..or all the facts.
that's all i meant by it.

now if this guys house was that well maintained, his subfloor stood no chance of being to high in MC. nor did the flooring.

it was an exposure after the fact..and that is not the installers fault.

and there plenty of instances where there is faulty material, faulty distributor storage,milling,finishing,and kiln drying.
most likely not the case here...I love Somerset..great mill.....

Thanks for all your comments I am coming to the conclusion that this was either an act of God, no ones fault, or one of the moisture readings taken before installation was incorrect.

The local company we bought the flooring from claims that the floor will relax over time. Visually it does appear that appear to be happening especially in the halls.

Has any one seen this happen before?

Thanks for your comments.