Popping or cracking sound in hardwood floors

Q: We just had new floors installed in a 1-year-old home, on the entire first floor, with a crawl space underneath. This is a redo job since the original floor had to be ripped up, because of major cupping due to moisture in the subfloor. Now we have new, prefinished floors (on a dry subfloor). In various locations, we hear a popping or cracking sound in hardwood floors.

Any ideas, before we go back to the installer?

A: This would likely be the floor shrinking. Especially if the tongue and groove are a very tight fit, any movement is likely to make a sound like that. Nothing to worry about yet. Try to keep the RH in the home as constant as possible, or avoid sudden, dramatic swings in humidity.

Follow-up Q: Thanks for the reply. What’s odd is that this started right after the installers left. We’ll keep an eye on it.

A: I’ve only had that happen on one of my installations. The tongue and groove of the pre-finished floor were so tight, I could barely pull them apart when taking the boards out of the box. With a tight fit like that, any movement is going to make a noise. Hope for the best.

Floors popping in a new home

Related Q: We are having a new home built and the builder has installed white oak hardwood. It has not been sanded or finished yet. We currently do not have the HVAC system installed. (We have a crawl space.) We have noticed that the floors are popping and we are concerned. We want to deal with this before they continue with the hardwoods and rest of the house. Is this something that needs to be corrected before continuing? We don’t know what to do and would appreciate your input. Thank you and I will be awaiting your response.

A: At this early juncture, since the floor has only been installed I think I would have someone come in and check the condition of the floor since installation. Someone needs to put a moisture meter on the floor. If there is room to get under this crawl space, I think I would cover the dirt if that is what is there and make sure there is good ventilation so that any moist air has a way to escape besides heading up through the floor. Depending on your location, I would also consider insulating the floor. Spray foam would be the best option I’m aware of.

Floors popping after installing on incorrect underlay

Related Q: Our solid white oak wood floor was installed over the wrong underlay. I hear lots of popping when I walk on them! My wife weighs half as much as I do and they do not pop as much for her. Half of the steps I take pop. The floors were installed a few months ago and were acclimated. I was told by the second guys that came in and fixed the top coat that the other guys used the wrong underlay. They used a thick felt underlay that was supposed to be an upgrade but has made it uneven. They put a bunch of nails in it, but that has not solved the problem. It is so beautiful, but it drives me crazy to walk around my house. We spent a lot of money on it!

I was thinking of buying the squeak no more kit or buying some screws as I think it needs to be put down securely. Thoughts? Suggestions of the best screws to use? Thank you so much for any help.

A: I haven’t heard of the ‘Squeak No More’ in quite a few years. Home Depot used to carry those once upon a time. They use a thin gauge screw which has the head snap off at a certain point leaving just a tiny hole. Whatever fastener is used you really need to find and go into the floor joists. Also if the ceiling below the floor is open you may be able to do some shimming or subfloor securing from below.

Follow-up Q: Thanks Craig. I’m pretty certain it is not the subfloor squeaking but the wood planks on top of the too thick underlay. Does that make sense? It is a brand new house but we used an underlay we should not have.

A: How thick was this underlay? If they used long enough cleats or staples and enough of them, every 7-9″ the floor should have been fine. Unless this underlay was something like, for example, a manufactured sound barrier, some of which can be about ¼” thick. If they used something like that and overlapped the joints then that would be a big mistake. If there are so many voids between the finished floor and subfloor then there may have been an issue with the subfloor.

Follow-up: Thank you for your help. I think it was this underlay: http://www.kuantumllc.com/ecommerce/product/108/100SF-Roll-Super-Felt

I don’t believe they overlapped it but I also think they used the standard length staples and did not put enough down. The guy came in and threw a ton of long finish nails in a lot of areas but there are still a bunch of squeaks. Long story short, I fired the guy that did the install after he couldn’t figure out how to sand and stain correctly. The second guys that came in did a good job sanding and staining but said all of the creaking was from the underlay. They saw it under there for a few spots they fixed and vents they added.

Living with a cracking floor

Related Q: I would like to know what the long term consequences are of just putting up with crackling floor boards versus a rip up and securing of the subfloor. Will the life of the floor be shortened?

A: If the floor has been sanded too many times movement like this would cause splinters to break off the edges of the boards. If you don’t have that happening and can live with the noise you are good. This doesn’t affect how long the floor will last. It sounds to me you have an old, 3/8″ thick floor. 3/4″ is much more rigid and less prone to flex.

3 thoughts on “Popping or cracking sound in hardwood floors”

  1. My house is 4.5 y/o and has 3/4” solid oak hardwood installer over basement. There probably hasn’t been a day it hasn’t creaked and popped. It’s a fairly energy efficient home. It’s really been popping a lot this summer with the AC on. In the winter, I have a humidifier on the gas fired hot air heating system.

    Anything I can do besides stabilizing humidity year round?

  2. I’m currently installing 1/2″ white oak flooring using the nail down method as described in the NWFA guidelines. Cracking and popping galore! I believe I know what the problem is, though. The manufacturer makes their tongue too thin. You can easily connect the boards and pull them apart — almost no friction at all. The problem with this is that there’s a very small amount of room for the groove side of the boards to move (remember, you’re only nailing down the tongue side, not the groove side). Thus, the board depends entirely on the tongue of the adjacent board to keep it down. Ironically, the the splines I purchased at Lumber Liquidators made specifically for 1/2″ flooring are a much better fit than the manufacturer’s own tongues.

    From my understanding, there are a couple solutions to this:
    1) This is on my second floor, so I plan on re-doing the ceilings on the 1st floor. When I do, I will screw from below to grab the groove side of cracking boards to make sure it does not move when stepped on. In order to calculator where to screw, I will drive a handful of nails down, take a picture with a measuring tape, and note the length of the nail (before installing flooring over the nail hammered flush to the sub floor). This will allow me to know exactly how long the screws need to be, and reference points to measure exactly where to screw on certain boards.

    2) For the other half of the second floor, and for the entire first floor, I will be using a combination method of glue/nail down. You basically use an adhesive to secure your underlayment (if applicable), then use lines of construction adhesive running opposite of the board’s direction, then nail down. What this will do is help secure the groove side of your boards to the floor below, preventing board movement. This method is described by some NWFA certified installers (will probably eventually be in the NWFA fuidelines), so it seems entirely legitimate

  3. I would like to know what the long term consequences are of just putting up with crackling floor boards versus a rip up and securing of subfloor. Will the life of the floor be shortened?

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