To Acclimate Or Not To Acclimate That Is The Question

woodfloorpro

You have 3/4 by 2 1/4 red oak strip flooring measuring between 6-8%. You have a 1 1/8 plywood sub floor measuring between 10-12%. You have ambient humidity at 45% and not likely to change in the next 2 weeks. Hvac is up and running and at normal levels. Why acclimate? The purpose of this thread is to start a discussion about the pros and cons, the do's and don'ts of acclimation.. Mike

rusty baker

If you don't acclimate and it fails, you have voided the warranty.

woodfloorpro

Ok. Good point if it is a prefinished floor. Manufacturers generally defer to NWFA guidelines that recommend at least 48 hrs of acclimation. What if it is site finished and you are providing the warranty. Mike

Floordude

Depends where in Oregon, your at.

Around the coast you could see an average moisture content of 13%. 50-100 miles in, it may be 8%. Then farther inland 7-5%.

So just by saying the subfloor is 12 says nothing to me. What was the top and what was the bottom of the subfloors MC, if it is over a crawl space or basement. What is the trim moldings readings?

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Teetorbilt

I was just onsite where bamboo flooring was put down without acclimating. The cust. was happy but IMHO it looked like BS, 1/16" gaps everywhere.

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woodfloorpro

I am very glad to see you guys weighing in. All good points. Which is the purpose of this thread. However I mentioned that the ambient humidity was not likely to change in the next 2 weeks which sort of implies maybe not, that it is stable. Exactly what would acclimating accomplish? Mike

sparehair

I don't know the math to calculate whether the three conditions you describe are at equilibrium ie even if you allowed the wood to acclimate there should theoretically be no moisture change in the floor. I think the assumption that the humidity will not change day to day is flawed. The key word being theory; I believe industry standard practice is to acclimate to allow for variations that theory does not predict or explain. I would want all of the wood breathing the same air for a couple days just on the basis of the tried and true method.

My physics prof once told me a story about radio towers. Theoretically three wires are all that is needed to keep the structure perfectly stable regardless of which way the wind is blowing. Assuming the wires are perfectly installed. In practice the towers have many many lines at various heights to account for inaccuracies of scale, human error etc...

woodfloorpro

You are very right about humidity changing. I know where I live I could get a 30% change within the day and that is common. Wouldn't the very nature of the fact that it changes that drasticly create an impossible situation for getting reliable acclimation?

Floorwizard

Fact is that MAYBE there are times you could get away with not acclimating.
But they are so hard to figure out.

How about acclimating everything, then the problem is solved.

That's why the manufacturers require it....

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woodfloorpro

You're probably right. As long as you can get the right conditions to acclimate properly. So many times we get into situations where the heating people will not fire their systems up until after we are done or if they do they won't honor their warranty. I am talking site finished now. I know technically we are supposed to break down the bundles and sticker everything site finished or prefinished. Simply just opening boxes doesn't do it. Often times there is still so much going on at the job site it is impossible to control the conditions. People in and out and leaving doors open and turning on and off the heating. I have one for you that perplexed me. I put down 2600 sq.ft. of 3/4 by 7" Chesnut site finished flooring on a new construction with plywood subfloor. The flooring was metered a little high at 10% so I allowed it to acclimate for 2 weeks and monitored the ambient humidity at 45%. The sub floor was normal at 8-10%. After acclimating I installed it which took me about a week and a half. I then allowed it to acclimate down for another 2 weeks. I then sanded to primary coating which took me another week and a half and final coated 2 weeks later. My finish was Bona Kemi Traffic. The problem was when I screened the floor for the final coat there was a ever so slight crown about 1/2 inch in on the edges of every board in the floor. Usually sanding a floor in a cupped state causes crowning when no other moisture is apparent but since this floor had a little high moisture content to begin with I could'nt figure out why the floor crowned. The only thing I can come up with is the boards were slightly cupped a little when I installed the floor. One reason that backs up that theory is when I installed the treads and risers I couldn't get the cut tight to the stringers that the contractor put up because the stringer was slightly cupped and 10" wide. And since the stringers came from the same people that provided the flooring it seems logical that they were a little wet at some point in time also. So if the floor was slightly cupped when I installed it the it would show a crown later. It did seem to me at the time that the flooring went down a little rough but sometimes that is normal with the smaller mills. I'am not entirely sure about this one. Anybody have an opinion.

Floorwizard

I am not sure....I am sure there will be others with more experience to chime in.

Just so you know...it's a tough read on posts like that without spacing....

FYI.

i am looking forward to hearing answers on your questions.

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fixitpete

Ha!

I'm working on my own house and I have a top of sub-floor reading that is between 12 and 16% and material is around 7%.

I feel it is so important to acclimate that I have installed a vapor barrier on the crawl space grade called Stegowrap 15 and 4" of concrete for a ratslab.

The concrete is still curing, I'll wait around 90 days from the date of the pour. Plus I want to put the floor down when it is warm. I'd rather have slight gaps than buckles.

I think acclimating is VERY important. Especially in my case where I have 3.25" plank Braz. Cherry.

IMHO.

wholesalefloors

Definitely acclimate your hardwood, engineered hardwood, bamboo, or laminate flooring. It makes it much easier to install the flooring because if the flooring is brought into a different environment where the humidity and temperature is different the flooring can cup, bow, and warp making it harder to install. It also reduces the gaps and buckling effects that can occur when floors are not acclimated.

rbsremodeling

I use my wood as soon as I take it out. I use to worry about moisture around my wood but not anymore.

If you have a good wood it should be fine. If you have a bad wood then you might have a problem. The older your wood gets the less prone it is to moisture damage

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Cole

Yowza!

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Floordude

I don't think anyone that has posted, really understands what their looking for, when conditioning the wood boards, prior to installation.

Just setting some boards out and waiting, is not what it is all about.


You know, wood floors have been around for how long?? Pretty sure wood and its characteristics, are well documented. The problem is, no one is teaching the what, why and how, wood needs to be installed at MC, of the average MC for the region in which it is installed. Regions that see big swings in MC used thin strip. Regions that stay pretty consistent, were able to use plank.

So, now everyone gets what they want, not what is realistic for there region, lifestyles and living habits. There is a reason a butt load of tiles have been used in Florida, California, and Arizona, compared to wood, until recently.

Then throw in a new wrench into the mix, that wood never experienced until recently(compared to how long wood has been used)...
HVAC, which is a whole new topic.

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Floorwizard

If only everyone was educated on the proper wood, conditions and environment of their area.
Problem is...most are not.

Acclimate baby!

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woodfloorpro

The reason I started this thread was to get you floor guys talking about acclimation and maybe

somewhere along the line some of you including me might learn something. As Floordude pointed out its

not just about bringing the floor in and letting it set for a couple of weeks. In fact if the conditions are

not right you could be doing more damage than not. You need to understand why. You need to

understand Equilibrium Moisture Content. EMC. You need to monitor moisture content of the subfloor,

the flooring and the ambient humidity. You also need a good understanding of the moisture swings in

your area the stability of the material you are using and what the conditions will likely be after the

customer moves in and brings the level of humidity to their comfort level. Achiveing EMC is the goal.

NWFA has a publication called "Water and Wood. How Moisture Effects Wood Flooring" I highly

recommend reading it and anything else you can get your hans on. Educate youself.