Humidity and laminate flooring


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Old 07-21-06, 06:35 PM
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Humidity and laminate flooring

I've read through hundreds of these posts in my quest to learn about laminate flooring. Want to replace carpeting in LR, DR, hall and 2BR (about 650 sf) in our condo. Subfloor is concrete and we're on the 2nd floor; 1st floor is open air parking. We live in Hawaii and after reading forum, bought a digital hygrometer/thermometer. Usually leave windows open and humidity is consistently 65-70% year round and 70-80 degrees.

I've seen posts that humidity should be around 50% or I could have problems. But if laminate is acclimated to higher humidity levels and humidity is consistently high here and isn't variable, will I have problems?

Also, seems the purpose of checking concrete moisture content is to determine if you need to put down a moisture-proof membrane under the laminate. If get laminate, I plan to put down 'Unisound Combi Floor' underlayment regardless of moisture content. Doesn't seem to be a reason to concrete moisture content; do I still need to check it?

Lastly, one BR had extremely high humidity and had a mold problem. We put in a dehumidifier and keep door closed with humidity around 50%. So effectively, we have two separate climates. Seems that as long as we keep BR door closed laminate will be OK. Does that sound right?

Thanks in advance for the help. Great forum!
 

Last edited by redsoxalso; 07-21-06 at 07:00 PM.
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Old 07-25-06, 10:55 AM
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HAWAII?!?! wow....some people have all the luck!!! ;~)

Welcome to the forums....

i think you're confusing laminate with real wood. with laminate, you just want the product to have acclimated to the room before you install, so that you can leave your 1/4" expansion gap around the room, and know that it's not going to expand that much or more that very night & become locked in ~ or contract and discover gaps showing in the morning.

as for underlayment & vapor barrier, follow your flooring manufacturer's specifications so you don't void your warranty. have you bought your laminate yet? what's the deal with that bedroom? why is the humidity so high in there? i'd be leary of putting down laminate in there. seems like you're asking for trouble - mold would just love to grow underneath that.

what does this mean?

Doesn't seem to be a reason to concrete moisture content; do I still need to check it?
 

Last edited by Annette; 07-25-06 at 11:09 AM.
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Old 07-26-06, 11:54 PM
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I am very lucky to be in HI.

I asked about humidity b/c I read a previous post from 'carpets done wright' stating something along the lines of don't install laminate if humidity is above 60% or it will fail (paraphrasing as I can't find the post to which I'm referring). I've let the laminate acclimate to the room and plan to undercut bottom of drywall to provide extra expansion.

My understanding is the only reason to measure moisture content is to deteremine if you need a vapor barrier. I'm putting down a vapor barrier regardless so I didn't think I need to check concrete moisture content.

The one bedroom with very high humidity doesn't get any sunlight or airflow, which is why we have a dehumidifer for only that room. No problems with mold in any other rooms after one year here.

Lastly, I read Prerry's sticky on making a floor flat. I don't have a screed and Home Depot doesn't carry (at least not here). 2x4s didn't look very flat...any suggestions on straight-edge/screed to pull Ardex GS-4?

Thanks for the response.
 

Last edited by redsoxalso; 07-27-06 at 01:46 AM.
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Old 07-27-06, 09:31 AM
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i would think that if the humidity will be consistently 60% (or 100%), then you'll have to acclimate the product to the 60% (or 100%). the product simply has to get to where it's going to be BEFORE you start installing.

i don't really know about the screed issue. i would think you could find a straight 2x4 though and turn it up on the 2" side & have it be flat.
 
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Old 07-27-06, 11:48 AM
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You do have to check concrete moisture even when putting a plastic moisture barrier over it. Especially in your situation, where dew point, is a problem and concensation forming on the top side of the plastic!!!

If this id a glueless click system, it gets really difficult to put together, the higher the humidity levels are.

I bought my screed at the ceramic tile supply house. Tile setter are suppose to use them to do exactly what I do with it, to flatten a substrate before setting tiles, or it can become a lipped or back-buttering nightmare. Also for setting on the popped line, to set tile straight off of.
 
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Old 07-29-06, 04:09 PM
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Project just keeps getting better...talked to the Ardex distributor for HI and he doesn't carry Ardex GS-4, so no one in the state has it.

Searched all day in stores and found Bostik D90 webpatch which is gypsum based and looks like it will do the job to fill in the low spots. Says it can only be laid on up to 1/2 thinckness so if I have to fill greater than that, I'll have to lay it multiple times I guess. Anyone used this product before or have a better recommendation since I can't get Ardex GS-4?

Haven't found a screed yet, but did get an 8 ft piece of 3" PVC and am finding high and low spots. Need to grind a high spot down.
 

Last edited by redsoxalso; 07-29-06 at 08:16 PM.
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Old 08-01-06, 12:28 AM
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This is like a Greek comedy...would have been a tragedy if I installed before researching. I called Maxxon, they referred me to the local distributor. Great! Finally got in touch with the local guy. He tells me I can use portland cement based patch on gypcrete. I tell him that's not what the rest of the world says and relate an article I read in tilesetter.com's Jan 06 edition. He sticks by his story. Not so great. So I've sent an email to Maxxon and will call them tomorrow to get a recommended patch available here.

Think I found a couple of places that sell an alum. screed and will check them out tomorrow. After sending $3K on flooring the $200 price for an aluminum screed is a no-brainer to have it done wright.

Mike
 
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Old 08-01-06, 05:22 PM
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I misspoke in a previous post. The patch material I currently have is DAP D90 webpatch and am wondering if anyone's used it previously?

Also, is it possible to seal the gypcrete with Redgard (or similar sealant) and then patch over it with a portland cement patch)?
 
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Old 08-01-06, 08:18 PM
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Even with a sealer, portland patch will blow your gypcrete off the floor, you need a gypsum based patch. D-90 will work perfectly if you can get it.
 
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Old 08-02-06, 12:27 AM
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Thanks Daniel. I can get D90. Do I need to use the Bonding liquid and floor leveler liquid additive they talk about on the D90 pkg?
 
 

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