Equilibrating Oak Flooring

[BOB OLINGER]

Last week I brought home about 12 boxes of solid oak flooring (3/4" x 3 1/4") which will be installed in our home. How long do I need to let this equilibrate in our home prior to installation?

[Cameron Wood]

In my area, flooring contractors let the material sit in bundles for a week. Longer is better, particularly as your flooring is wider than the traditional 2 1/4", and weather has been extreme.

[Mel Fulks]

I have wondered if the contractors just make that a standard statement to keep the “when are you gonna do MY floor” calls down. It’s the
kiln drying that makes flooring a ‘space age product’ .

[Robert London]

A week should be plenty. Some will put in down in 48-72 hours if it's standard 3 1/4" width.

Wood being properly kiln dry at the mill is the most important. I put down ~850 SF of 6 inch rift and quarter cut red oak in my entire downstairs.

It was unfinished and think I waited a week or so before I stapled it down. I had long 6-12 foot lengths and being 6 inches wide, I wanted to wait a little longer.

[Cameron Wood]

I have wondered if the contractors just make that a standard statement to keep the “when are you gonna do MY floor” calls down. It’s the
kiln drying that makes flooring a ‘space age product’ .


Wood flooring is not a space age product- where did you get that idea?

Hardwood floor contractors are regularly squeezed, falling late in the construction schedule while sheetrock, plaster, and painters are still adding a bunch of moisture to the site
and the GC is trying to make up time.
Guess who is left holding the bag when thousands of SF of flooring cups and the homeowner is irate?

[Maurice Mcmurry]

Acclamation guidelines should be in the labeling and / or instructions provided with the product.

[Mel Fulks]

Got the facts by over 40 years of using wood and cutting off ends of different woods ,soaking them in water and comparing how they
moved. Of course the manufacturers want to scare you. Otherwise the stuff would be daily seen on rainy days tied down tarpless getting soaked with rain. “Don’t worry ,Joe it’s garanteed!” It is now mainly sold in narrow widths , it’s air dried then kiln dried. All it takes to make sure it’s gonna work is to scare guys
into buying a tarp and using it , and not putting down the flooring until the roof is on. Much of flooring in old houses was over time
shrunken by getting wet , with mops ! ,as well as muddy shoes. The wood expanded while wet , then like a stuck elevator ,full of fat
people all eating at once ….they got mashed together. Unlike the FEP…the wood shrinks as it can not “decompress”. That is called
“compression ring set”.

[Kris Cook]

I can tell you from my experience, I have installed Oak flooring in two different homes. The first one was 3-1/4" Red Oak and I let the wood sit in the house for about a week and there were no issues. I live in Montana and the flooring on that install was done in the spring.

Last winter I installed a White Oak floor in our living room. I believe the widths were 4",5",6" and 7". I let the wood sit in our heated front porch for a week to ten days and verified the MC at 6%. We have a free standing propane stove in the living room that is rated to be installed on wood floors. I see some gaps in the planks that are in front of the stove this winter, not bad but hoping they will disappear come spring. We need to be running a humidifier in the living room which would help.

I don't know what the humidity swings are in your area. Might be good to know how long the material sat in your locale before you purchased it.

Bottom line is - you should be good with a week of acclimation. I think installing wood flooring in the winter is generally better (assuming you live in an area with lower humidity in the winter).

[Kevin Jenness]

Acclimation without regard to conditions is poor practice. Really what you want to know is the flooring's moisture content at installation relative to its expected equilibrium moisture content range in service. If you let your kiln dried 6" flatsawn oak flooring acclimate at 60% relative humidity in a Vermont summer you will have gaps big enough to throw a cat through when the woodstove is cranking in February. Any flooring installer who doesn't have and use a hygrometer and a moisture meter is flying blind.

[Richard Coers]

Depends where the wood flooring was when you bought it. If it just came off the truck or out of a cold warehouse, I'd open the boxes and let it sit 2 weeks. Especially this time of year. With furnaces running full time around Christmas, most homes are bone dry right now.

Mel, you know the space age only started in 1957 when Sputnik was launched, right? That makes kiln dried floors a predecessor of the space age.

[Ron Citerone]

I wonder how long they acclimate the hardwood flooring on the space shuttle? :D Houston, we got a problem, gaps in the floor boards!


Depends where the wood flooring was when you bought it. If it just came off the truck or out of a cold warehouse, I'd open the boxes and let it sit 2 weeks. Especially this time of year. With furnaces running full time around Christmas, most homes are bone dry right now.

Mel, you know the space age only started in 1957 when Sputnik was launched, right? That makes kiln dried floors a predecessor of the space age.

[Joe Calhoon]

Acclimation without regard to conditions is poor practice. Really what you want to know is the flooring's moisture content at installation relative to its expected equilibrium moisture content range in service. If you let your kiln dried 6" flatsawn oak flooring acclimate at 60% relative humidity in a Vermont summer you will have gaps big enough to throw a cat through when the woodstove is cranking in February. Any flooring installer who doesn't have and use a hygrometer and a moisture meter is flying blind.

Well said Kevin,
A lot depends on your location. Here in the Colorado mountains it is very dry. Kiln dried wood stored in unheated warehouses arriving by truck in winter can pick up moisture. The good floor guys here are very particular about letting the wood acclimatize before installing. Keeping the heat up and fans to move the air. There have been lawsuits about flooring shrinking.

Contractors call the flooring moisture meters “schedule meters”

[Maurice Mcmurry]

Anybody had to follow up after bed bug remediation? Talk about a flooring destroyer. Be careful who you let come over for a spend the night, (not a personal experience but helping with the aftermath now). The only thing worse than 48 hours at 140 degrees for floors is a leak or flood.

[Mel Fulks]

When I was a kid there was always something about bed bugs in every magazine and most news papers. There were lots of kill methods ,
but home electric washing machines with hot water and bleach is what really cut ‘em down. So much better than brushing your clothes
off ! My Grandmother had rental properties, and renters back then always asked about bed bugs and what property owners would do to
fight them.

[John TenEyck]

So what combinations of RH and % MC are correct for installation? Your input points out the problem but doesn't provide an answer. And doesn't the substate you're putting the flooring down over effect the decision? Curious minds want to know. Thanks.

John

[Kevin Jenness]

So what combinations of RH and % MC are correct for installation? Your input points out the problem but doesn't provide an answer. And doesn't the substate you're putting the flooring down over effect the decision? Curious minds want to know. Thanks.

John

I'm not sure if your question is directed at me. I would be guessing at the op's specific situation. Here in northern New England, I would shoot for a mc of 6-8%, same as for cabinetwork. I don't know why the substrate would make a difference, except that in floor radiant heating might suggest a lower installed mc and a new concrete slab might call for more attention to moisture sealing under the flooring.

[John TenEyck]

I'm not sure if your question is directed at me. I would be guessing at the op's specific situation. Here in northern New England, I would shoot for a mc of 6-8%, same as for cabinetwork. I don't know why the substrate would make a difference, except that in floor radiant heating might suggest a lower installed mc and a new concrete slab might call for more attention to moisture sealing under the flooring.

Yes, the question was directed to you, Kevin, but I'm happy with all input. So if you install the flooring at 6 - 8% MC in the Winter what happens next Summer when it wants to swell? Will it just slide under the baseboard if you left enough space for it to do so? Or the same 6 - 8% flooring put down in the Summer; what happens next Winter when the subfloor shrinks, or does it not? What specific numbers are competent flooring folks using to decide when it's OK to install?

John

[Kevin Jenness]

I'm not a flooring installer, just an experienced woodworker who has worked on and around residential construction for a long time. Since t&g flooring is laid tight it's wise to install it somewhere between its expected mc limits in service, preferably toward the lower end. A general rule of thumb is that problems tend to show up when the work gains or loses more than 2% mc from when it was fabricated (or in the case of flooring, installed). If very dry when installed flooring is likely to develop compression set in humid periods and show gaps when the atmosphere dries out, if installed at a high mc the pieces will simply shrink apart later. Most flooring I have seen in the past 20 years gets glued down. In an extreme situation like flooding the floor may expand under baseboard but it's more likely to develop compression set or even buckle upward. I haven't seen problems related to underlayment moving but that could happen. A good flooring mechanic would test the underlayment as well as the flooring to avoid problems. Most of the jobs I worked on were big, protracted projects with competent supervisors so the risk of major moisture problems due to fast schedules simply didn't come up.

Flooring installers may have looser or tighter standards for installation than I would think wise. Some are more knowledgeable about wood movement than others and as with building contracting in general aggressive schedules can have a negative effect on quality.

[Tom M King]

I put 5" White Oak in every spec house I built, after the first few. There was a supplier then in Richmond, Va. that kept it in a heated warehouse. I had a moisture meter to check it to see where other inside wood was here, and it was always good enough to put down when I got it back. I would go get it myself, and pick the driest spell to go. That place has changed hands, and locations a couple of times since then, and now is owned by some National Chain. I don't know if they still heat the warehouse, but I doubt it.

I would always leave 1/2" all around under 3/4" baseboard and door jambs. The center board in any room was glued to the subfloor with construction adhesive. It would all be tight in Summer, but you could slide a sheet of paper between boards in Winter. All were over a heated daylight basement on a lake lot. Never had any complaints.

I finished it before trimming out, and my helpers and I kept new shoes at the door to change into when in the house. I bought them new shoes, and they were glad enough to get them to change when required.

[John TenEyck]

Thanks Tom. So what was the MC of the flooring and of other wood in the house when you installed it? I imagine your schedule varied from year to year. If so, you most likely installed those floors at different times of year. What was your strategy to account for differences in MC between the flooring and house?

John

[Tom M King]

My schedule was about the same every year. I built one house for sale with two unskilled helpers. I'd start in the Fall, finish the inside over the Winter, dress up the outside in Spring, and sell it the first of the Summer. Then I'd take the Summer off. I only built one house a year (for 33 years), but did everything myself except install HVAC units. I did the ductwork, but knew the equipment would fail at some point, and I didn't want the callbacks. No boss, and get up to produce work every day. I could build a house for half of what I could sell it for.

By the time I was ready for flooring, the house was closed in, insulated, walls finished, and heat working. The floor went down after the walls were finished. So it was about the same time every year.

In the house MC would be about 8-9% then, and that's what the floor would be too when I bought it. The last few years, I did buy it early, and leave it in the heated house until I was ready for it.

I quit doing that in 2007. It looked like all the other builders had gotten smarter than me then, and I was a bit bored with it anyway. I didn't want to have a house on the market in 2008. I went full time to working on old houses.

[Ron Selzer]

been watching gym floors for over 20 years now, in heated only gyms to heat and air-conditioned gyms. When water floods on the floor then you will see the floor buckle up. Fans get brought out and run, some gyms would pull baseboard and run fans pushing air under the floor. One heat only gym floor had been wet enough times that a section got replaced, gym was 80 yrs old and floor was 30+ years old. when all done 6 months later had to hunt to find problems with floor that had not been replaced.
All gym floors that I have examined have been nailed down with a gap every 5-6 boards, metal flat washers about 3/8 hole were used as spacers and then removed. The center floor area of the gym would move enough you had to look hard to see the space after one year. Unused and low usage areas of the floor you can find the gap 10 years later. The heat only gyms would buckle the flooring if the summer was real hot and high humidity that summer and doors were open every day, not ever year, some years floor stayed flat. The floor would recover in time to play basketball in the fall.

[Joe Calhoon]

I’m not a flooring contractor either but hear a lot about flooring problems on jobs. A friend of mine manufactures flooring from antique lumber.
kiln drys it in his own kiln, very pro operation.Most homes here have in floor heat and that can cause problems. Most use gypcrete or concrete under the flooring and that can retain moisture after pouring for quite some time. He recommends getting that dried down very well before laying the floor.
Houses nowadays are highly heated, cooled and humidity controlled compared to say 30 or 40 years ago. This can cause many problems with woodwork.
here is a interesting page from the AWI quality standards book.
492823

[John TenEyck]

Thanks Tom and Joe for the added info. What I'm hearing you both say is flooring should be installed when both the wood and subfloor are at low moisture content. I guess that makes sense as long as enough space for expansion is provided under the baseboards. But it doesn't address how commercial flooring installers deal with installation in mid Summer in most areas of the country, especially if the house does not have AC. I'm just trying to understand how they deal with wood movement to best avoid problems.

John