I have a new installation of 4" hickory installed. The wood was brought into the new construction location in January (North Carolina), heat was on in the house and the wood sat in the environment 2-3 weeks (or longer) before it was installed. Now that it's spring time and more humid, the floor is popping like crazy. It seems to be worse the day after we've received rain. The floors are unfinished at this point. I believe the installers did not allow enough expansion gap and now the boards are tight against each other. I am unsure of what is causing the popping noise. Is it the nails? Or the wood itself? Any suggestions on what should be done? We're trying to get the house finished and this is a major concern right now.

Thanks.

Lorie

Usually, an unfinished floor will react to changes in temp and RH very rapidly. So the noises you hear are common in an unfinished floor, especially hickory, which is not very stable ( it's a mover ). I would hold off judgment until the floor has been completely finished and you have lived there awhile. The boards are supposed to be installed tight together. If they weren't, you would be complaining about gaps. This is solid wood doing what solid wood does. You could discuss the nailing schedule, the type and length of fasteners used and a myriad of other technical items that could possibly lead to excessively noisy floors. To determine that, you would need a third party wood flooring expert.

Get your de-humidier(s) running, and/or your air-conditioning system.
Hickory loves to pick up air-bourne moisture and will do so quite rapidly.
This is even more of a concern when the floor remains unfinished for long periods. You will see some major concerns this summer if you do not control the environment in which the floor resides.
The relative humidity at time of install should have been within normal live-in conditions, and maintained that way since. What the range is is determine by the climatic conditions of your area. In Toronto the acceptable range is between 35% to 50%. Check your meteorlogical peeps in your area for your range.

Sorry, I realized after I posted that my comment was mis-leading. You need to maintain 35% to 50%. Knowing the climate in your area will help determine what facility you will need to maintain this in comparison to what the range for your area is outdoors.

Acclimated to winter time heating and installed really dry and tight...

The popping is, it gaining moisture and trying to swell. Don't be surprised if the floor cups, or in worst case, buckles.


Acclimating and installing tight with the heater pumping and drying, is not the smartest thing to do. As spring and summer come on, the floor is going to want to swell, with no where to go but upwards.

Thanks to all who responded. I had the subfloor rep at the site yesterday. It appears the OSB is functioning as expected but has a higher moisture content (12-14%) than the hickory (6-7%). We've actually ripped up the hickory in several rooms. I'm going to take up the felt paper as well and see if the two products will acclimate closer to the 4% max difference that is desired. The subfloor rep believes the hickory was put down when the moisture difference was greater than 4% and then when the hickory absorbed more water and the OSB shrunk, the nails loosened and thus the popping and movement.

Any further thoughts are always appreciated.

That subfloor MC is higher than it should be. That suggests there is moisture from below. Is your home built over a crawl space or a basement? In my relatively mild climate, 8 to 10% is the norm for subfloor MC. I think some investigation needs to be done underneath your home. Of course, another possibility is that the subfloor was rained on during construction ( quite common ) and being OSB, is taking a very long time to dry. The installers laid the flooring when the subfloor was still too damp. This is what moisture meters are for.

That floor was fixing to explode off the substrate!! You were hearing the ticking time bomb.

Glad you figured it out.

If this is new construction, I can see why the OSB is still high in moisture content.
Wet trades working during the day, closing the home up at night and to save money, the HVAC turn way down so it doesn't run and burn money when the workers are not there. The humidity from the wet trades absorbs into the OSB, which takes 3-4 times as long to loose moisture than it does plywood.

The wood was stressed and was yelling at you.

We've had the hickory pulled up in several areas. I've taken moisture readings of the subfloor and the hickory. It appears that the subfloor is now in the desired 10-12% range with the hickory measuring 6-8%. Sounds like ideal conditions to put the floor back in place. My concern is two-fold:

1. Do I need to pull up ALL of the wood and put it back down? I probably have about 2500 square feet. I've pulled it up entirely in the master bedroom but only partially in other areas where the popping was intense. The "relief" of pulling up sections seems to have allowed the rest of the floor to relax.

2. What should I use to put the wood back in place ... glue, shanks or staples? The wood was originally put in place with 2" staples (dipped in glue).

Thanks.

2 inch cleats

The subfloor mositure content could have been in the zone when the floor was installed. Is the crawl space/basement properly vented? Is the subfloor covered underneat and or the dirt if its a crawlspace? Grading issues around the home....landscaping not finished water ponding around the home? HVAC most likely is not running as should be I bet as in the case of most new construction.

There is a full walkout basement underneath. The waterproofing that was installed around the subterranean walls is top of the line products (have to look up the paperwork for the details but I believe it cost in the neighborhood of $30-40k). There are no moisture problems in the basement. We do have a residential dehumidifier running in the unfinished basement space - just to be sure.
There are no grading issues. The landscaping is not complete but the gutters are in place and the downspouts are tied into buried corrugated pipe.

HVAC is running - set anywhere from 72-76 degrees. (This is cooler than I keep my own home.) Doors and windows are kept shut during the construction.

Only thing that makes sense to me is that the subfloor was too wet when the hickory went down. The OSB used is the Weyerhauser Structurwood Edge Gold product - top of the line, but does take longer to dry out since it is comprised of wood strips, wax and resin.

Any other suggestions?

Thanks.

I agree.
You have educated yourself very well.

Just to provide an update ... We've had sections of the hickory pulled up and put back in place with Bostik EFA+ glue. Every 4-5 rows (of 4" planks) are being blind-nailed (or stapled).

I initially thought the fasteners used for the installation were 2" staples with the tips dipped in glue ... but I was wrong. The installer simply used 2" Bostitch staples with 1/2" crown (no glue on the tips). Keep in mind this is what is being used to hold 4" hickory planks in place. The more research I've done, the more I'm convinced the problem doesn't lie in the moisture content or difference between the subfloor and the hickory - but in the fasteners themselves. Everything I've read states that moisture issues will cause cupping. Any comments that refer to noisy floors mention the fasteners as being the culprit. Thoughts and comments? (By the way, I still have popping in the upstairs areas - nothing has been pulled up yet and I know that the MC and difference is good.)

Another quick question ... since I am a general contractor and don't need to use a moisture meter on a regular basis, what do you recommend I purchase? I've seen cheap ones on ebay for $20. Are these adequate considering I won't be using it on a regular basis? (The one I have been using is a borrowed Delmhorst J-4 - but they can be quite pricey.)

Your input is appreciated.

Thanks.

Lorie

At this point, it is all conjecture. You have stated that you found the subfloor MC to be much higher than it should have been, although it appears to be drying now. Now you believe it's the fasteners. I have been laying wood flooring for 30 years, back before there were pneumatic staplers and we nailed them down with Powernailer model 45's and cleats. We had install problems back then. The staple is not the sole source of a noisy floor. Often, it can be a combination of things that cause problems. It is all irrelevant as the installer is the one who is to ensure the site is ready and suitable. Question, did you hire a licensed hardwood flooring contractor? Did one of your guys install the flooring?