I did a search for this question, but after viewing 150 of the latest HW messages didn’t come up with an exact answer to this question.
We are getting ready to install the HW flooring in our house I am GC’ing. It’s 3-1/4″ Red Oak, Bruce prefinished. It’s been in the house for a week and the moisture readings in the subfloor have been checked and are ok. Heat is on (we live in Annapolis). First floor is over a vented crawl (can’t use ventless in a flood zone) with typical second floor above.
My question concerns the time of year and expansion. In the last house I GC’ed for ourselves, we did the HW install in July (one day during that install it hit 100 with no AC yet in the house) and over the 17 years we lived there the floor was fine. This floor will be installed in January.
For a January install is there a concern over what will happen come summer regarding expansion and possible cupping? The installer is going to install it over roofing felt.
Thanks for your time.
Runnerguy
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One question? Did you put down some plastic on the crawlspace dirt? It would help with moisture.
Yes. We have 6 Mil plastic in the crawl.
Runnerguy
I install such with 3/8"To the SR surface, but that is also usually up from the subfloor 3/4" or so leaving more space available.
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runnerguy,
you don't have to worry about wood expanding lengthwise. It expands so little it will never be a problem.. width is another matter.. In a week you don't really have the wood acclimatized to the site... all you have on prefinished wood is the ends and bottom to expel surplus moisture out. If you test the wood for moisture you are only testing the top 1/4 inch at most.. the middle is where the wood is that needs to yield up moisture not just the surface.
On the other hand the wood you are nailing to is far from dry itself.. most wood is around 15 % moisture maybe slightly more and it will take a while to yield up all the moisture that's in it. In the winter you can figure about 4 months once the heat comes on.. before the subfloor wood is fully dry.. down to around 7% moisture..
OK so you have a moving target.. damp sub floor wood and slightly damp finished floor wood..
Slam the wood together tight the same way it normally gets installed and next summer it shouldn't cup as it swells from humidity. Next winter the wood will shrink as it always does during the dry winter time and there will be slight gaps between some of the boards. Same as there always is.. leave 3/4 inch on either side for expansion cover the gap up with 1/4 round or whatever base molding you use..
I've noticed some gaps in our floor because it is so dry right now. We have a leaky house with the furnce on. A humidifier would help in the winter.
Not to highjack your thread, but I live in a flood zone and I closed up my crawl space My house was very cold in the winter(Northern NJ) with the vents in the crawl space. I replaced the vents with small basement windows and I open them when a flood comes. A sealed crawl with a humidifier has helped a great deal.
Legally those windows have to be automatic blow open opening's of a certain size
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I'm confident there is no way to judge how the floor will react unless you have a moisture meter to actually measure the moisture content of the wood and of installed floors in your climate.
For instance we installed some prefinished bruce oak, half was dried to be used in the rocky mountain states and half was shipped in from a supplier on the coast. Hardwood is generally dried to within a percent or so of what's common for your area, but that's not always the case, especially with special orders coming from who knows were and discount outlets who don't really care where the wood comes from or how dry it is as long as it's cheap.
In the boxes, your flooring will aclimate rather slowly. Out of the boxes but tight stacked it will still take weeks to make a significant difference. That's just the way it is.
There isn't anything as useful for flooring as a moisture meter.
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Thanks everyone for your helpful replies. I figured we'd be ok as HW installation doesn't stop in winter. It's just that last time worked so great with a summer install so this is a little bit different.
Runnerguy
I've had difficulty with winter installs. I've put down hardwood (cherry once, maple once) at 7% in the winter, and gotten buckling in the summer. Not enough to ruin the floor, but very noticeable. My local mill makes the flooring themselves and Kiln dry it and store it at 7%. They under cut the t & g joint so that when it's touching on the top side of the joint, there is a small gap in the underside. When it swells in the summer, there is a pronounced bulge up at the joints, but the boards stay put. It lays down again in the winter, so you wouldn't want to sand it out.I always dislike laying floors in the winter, but am going to have to do one in a month or so. Just about the worst time. And even with a moisture meter, I'm at a loss for how to prevent the problem.I too am open for suggestions on how to do it better.Steve