# hardwood flooring underlayment.



## bluebird5 (Dec 13, 2010)

I am about to lay some 4" soft maple over advantech subfloor which is over a crawlspace. I have had my 6 mill poly down for about a week. Subfloor is at 10% and the maple is at 6% moisture content.

I am wondering which underlayment to use. I do not want roofing felt. I really don't want aquabar either because I can smell the asphalt in it. Should I use a siliconized paper or a wax paper? I have also considered rosin paper. 

Here is my thinking is that although these vapor retarder papers block or slow down moisture from the subfloor from entering the hardwood, eventually the moisture will get to the hardwood. So am I better off just using rosin so that the 2 woods get to the same moisture content and then sand and finish or are the vapor retarders better? 

Will my hardwood eventually get to 10% or will the vapor retarder prevent this from happening?


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## pinwheel (Dec 7, 2009)

You've already made your excuses for not using the proper hardwood paper. Go ahead & just use rosin paper & get ready for the client to call your back when their floor cups.

I personally won't lay a sanded floor without ASU or LSU hardwood paper under it. My reputation is way to valuable to risk a cupped floor. I also won't lay a sanded floor without making sure permanant HVAC has been turned on & running long enough to bring down the moisture content in the subfloor.


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## bluebird5 (Dec 13, 2010)

pinwheel said:


> You've already made your excuses for not using the proper hardwood paper. Go ahead & just use rosin paper & get ready for the client to call your back when their floor cups.
> 
> I personally won't lay a sanded floor without ASU or LSU hardwood paper under it. My reputation is way to valuable to risk a cupped floor. I also won't lay a sanded floor without making sure permanant HVAC has been turned on & running long enough to bring down the moisture content in the subfloor.



I;m not trying to save money, I just want to use the right product. I usually use 15# felt, but I want to get away from the asphalt. What would you suggest? This is for my personal house.


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## pinwheel (Dec 7, 2009)

bluebird5 said:


> I;m not trying to save money, I just want to use the right product. I usually use 15# felt, but I want to get away from the asphalt. What would you suggest? This is for my personal house.


Aquabar-B or ASU 15 hardwood paper. Also get the AC running & pulling moisture out of the sub floor before putting down the hardwood.

The flooring & subfloor will eventually find a balance in MC, but until they do, if you don't use a moisture hardwood paper, you're going to get cupping till they find that balance.


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## bluebird5 (Dec 13, 2010)

pinwheel said:


> Aquabar-B or ASU 15 hardwood paper. Also get the AC running & pulling moisture out of the sub floor before putting down the hardwood.
> 
> The flooring & subfloor will eventually find a balance in MC, but until they do, if you don't use a moisture hardwood paper, you're going to get cupping till they find that balance.



I am thinking of using this silicone paper which is usable over radiant heat. .47 perm without nails and 0.712 with nail holes. I believe that it is pretty close to the same perm of aquabar and has zero voc. Have you ever used this? What do you use over radiant heat? 

http://www.lumberliquidators.com/ll/c/White-Silicone-Vapor-Paper-Sq-Ft-SILPAPER/10021412


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## Metro M & L (Jun 3, 2009)

I've torn out floors with asphalt next to rosin over crawl space. It's no contest, rosin is cupped with severe gaping from crushed grain following swelling; tar paper is flat with slight gapping. 

Pin will tell you aquabar, I will tell you tar. Either way, it two guys who have been doing hardwoods for decades and a piece of plain paper is not going to work.

I've read 2 percent and 4 percent max difference between the substrates. I've laid many times with a four point difference and haven't had any problems. Make sure you read the manual on your moisture meter. They can be off by 2 to 6 percent depending on temperature and species. At least the lignos anyway.


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## bluebird5 (Dec 13, 2010)

Metro M & L said:


> I've torn out floors with asphalt next to rosin over crawl space. It's no contest, rosin is cupped with severe gaping from crushed grain following swelling; tar paper is flat with slight gapping.
> 
> Pin will tell you aquabar, I will tell you tar. Either way, it two guys who have been doing hardwoods for decades and a piece of plain paper is not going to work.
> 
> I've read 2 percent and 4 percent max difference between the substrates. I've laid many times with a four point difference and haven't had any problems. Make sure you read the manual on your moisture meter. They can be off by 2 to 6 percent depending on temperature and species. At least the lignos anyway.


Yes the moisture meter says it can be off plus or minus 2%. It also says that it will read less moisture in denser wood and higher moisture in less dense wood. So it is really hard to push into the maple floooring and I can shove it all the way into the advantech. So it is hard to truely know what the moisture content is.


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## pinwheel (Dec 7, 2009)

bluebird5 said:


> I am thinking of using this silicone paper which is usable over radiant heat. .47 perm without nails and 0.712 with nail holes. I believe that it is pretty close to the same perm of aquabar and has zero voc. Have you ever used this? What do you use over radiant heat?
> 
> http://www.lumberliquidators.com/ll/c/White-Silicone-Vapor-Paper-Sq-Ft-SILPAPER/10021412


You're worried about a little tar, yet you provide a link from lumberliquidators. Dude, that's laughable.:laughing:


No, I've not used that paper.


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## mako1 (Sep 1, 2013)

I think the 6% reading is off some on you're flooring.Especially in TN this time of year.Hardwwood is usually only dried to 7% to begin with and will usually rise some to a ambient MC.


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## PrecisionFloors (Jan 24, 2006)

Over thinking once again. Use aquabar and be done with it. The smell dissipates pretty quickly. The over concern about v.o.c these days is getting ridiculous. I'm damned glad building this country was already done before this generation got here... Can you imagine anyone under the age of 40 throwing hot rivets or pipe fitting now a days...


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## mako1 (Sep 1, 2013)

PrecisionFloors said:


> Over thinking once again. Use aquabar and be done with it. The smell dissipates pretty quickly. The over concern about v.o.c these days is getting ridiculous. I'm damned glad building this country was already done before this generation got here... Can you imagine anyone under the age of 40 throwing hot rivets or pipe fitting now a days...


+1 I am 60 this year and been in the trades since 16.I should have been dead year ago with all of the stuff I've dealt with.Asbestise,all kinds of paints,solvents and other carcinogens including the dreaded milk for awhile just to name a few.
My dad was a salesman and never did any manual labor in his life .Died at the age of 51 with a heart attack and never partied near as much as I have.
Not saying to not take safe measures but don't be a prisoner in your own world either.


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## bluebird5 (Dec 13, 2010)

pinwheel said:


> You're worried about a little tar, yet you provide a link from lumberliquidators. Dude, that's laughable.:laughing:
> 
> 
> No, I've not used that paper.



So what to who sells a product. They didn't make it, they just sell it. If I bought aquabar from lumber liquidators would that be laughable too? If you have something available to you around the corner, are you not going to go there to get it or will you drive 30 miles to your "supply house" through heavy traffic for the same product? There are other brands of silicone paper, I just wanted to show you an example.


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## Metro M & L (Jun 3, 2009)

I drive across town to get the right tool, finish, lumber all the time. If it's worth doing, and everyone else does it for a living , it's worth arguing with them about what they have years of experience in. Wait, I'm don't think that's how that saying goes...


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## pinwheel (Dec 7, 2009)

bluebird5 said:


> So what to who sells a product. They didn't make it, they just sell it. If I bought aquabar from lumber liquidators would that be laughable too? If you have something available to you around the corner, are you not going to go there to get it or will you drive 30 miles to your "supply house" through heavy traffic for the same product? There are other brands of silicone paper, I just wanted to show you an example.


maybe next time you want flooring advice, you should start the thread saying you want us to agree with you & your choices rather than sharing our experience & expertise.


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## bluebird5 (Dec 13, 2010)

Well I ended up getting the aquabar.


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## bluebird5 (Dec 13, 2010)

pinwheel said:


> maybe next time you want flooring advice, you should start the thread saying you want us to agree with you & your choices rather than sharing our experience & expertise.



No not asking you to agree. All I was asking about was if anyone had any experience with the silicone paper.


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## Xtrememtnbiker (Jun 9, 2013)

We've used the silicone paper. Because that's what the guy at LL sold us. Pin has me reconsidering.


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## MIKE ANTONETTI (Jul 17, 2012)

bluebird5 said:


> So what to who sells a product. They didn't make it, they just sell it. If I bought aquabar from lumber liquidators would that be laughable too? If you have something available to you around the corner, are you not going to go there to get it or will you drive 30 miles to your "supply house" through heavy traffic for the same product? There are other brands of silicone paper, I just wanted to show you an example.



I think Pin was referring to the excessive formaldehyde in LL products and you being concerned about VOC's

I personally don't like hardly any Chinese products with some exceptions, partly Americans are to blame as we all want cheap so we can buy other cheap stuff.

The air in our home is open to outside air a lot, mostly frickin allergies from pollen.


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