Acclimatization of Hardwood Flooring I
I say NO, they Say YES!

Acclimatization of hardwood flooring is the process of letting your wood flooring come to equilibrium with the moisture content in the environment where it is being laid. One might ask first.. why bother?

Well wood is like a sponge. It absorbs and give off moisture constantly in response to the environment it lives in. Like the sponge it expands and contracts in size to reflect gained or lost moisture. But with a sponge we don't care what size it is as long as it does the job. With flooring we do care.

Hardwood floors that absorb too much moisture buckle and look unsightly. Floors that give off too much moisture shrink, creating gaps between the individual boards and encourage moisture penetration and the associated damage, below the finish. So this is not a trivial conversation, but rather a key ingredient in a successful hardwood floor installation.

So there are 3 key questions:

  1. Do you need to acclimatize your hardwood flooring?
  2. If you do need to acclimatize the flooring, to what relative humidity?
  3. How do I acclimatize my hardwood floor if I need to?

Do you need to acclimatize your hardwood flooring prior to installation?

NOTE: Relative humidity varies with geographical location of the manufacturer and customer, so change the numbers in the conversation below to reflect your local relative humidity conditions.

So do you need to acclimatize your hardwood, well that depends! Most of the better hardwood flooring manufacturers dry their flooring to 45% moisture content (the average relative humidity for Central Ontario). They know that spring-winter variations can go from 35-55%, thus they aim for the mid point.

Equally important fussy manufactures encourage their retailers to store the material in humidity controlled warehouses to maintain this moisture level. This is why much of the offshore made product has problems. It spends 4 months in the hull of a ship, picking up moisture before it gets to you.

Thus if your geography dictates a relative humidity in this range of 35-55% AND your floor manufacturer equalizes their flooring to this mid point, then the discussion need not go any further.. you are ready to install your hardwood flooring.

For the rest of us, life is not perfect and your flooring is not at the right "midpoint." so you must address the humidity issue more seriously. Here's some examples:

1. Your local environment is different from the norm i.e.. excessively dry or humid...like lakeside property, or dry prairie weather etc. but remember we are talking about the yearly AVERAGE.

2. Less expensive offshore flooring that you are suspicious has not been dried adequately .

. . but then I don't really feel this is a good buy to start off with... as it is very hard to get a floor consistently dried across all boards, using your home environment as a dry kiln. That's why I say no to acclimatization and everyone else says yes. I agree with the principle and the NEED but not with the feasibility of execution!

Now this is where it gets tricky. Our third key question was how does one acclimatize a hardwood flooring? My first answer is that it is not possible and you are best to discuss this matter with your local flooring store and see if they either have a "brand" or "style" of hardwood flooring that is fabricated under conditions more suitable to your location.

As an example you might use an plywood based engineered floor with its greater stability for more nasty environments, or a glue down installation that with a good glue can control moisture absorption from underneath.

If you still come back and want or need to acclimatize a hardwood floor, use the link above for a further information. I've also added a more complete discussion for question number two on why you want to acclimatize your hardwood floor to the midpoint of your home's relative humidity range.

My own opinion is that for the best hardwood flooring installation, flooring must be made to the correct moisture content-- at the time of manufacturing -- to lay a consistent, uniformly moving floor.

Further Information:
Hardwood Flooring Installation Techniques
Hardwood Flooring