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How to Fix Squeaky Hardwood Floors From Above and Below

Unlike many laminate floors, true hardwood flooring is almost invariably nailed or glued down. Which complicates fixing squeaks. It can be pulled up, but is it worth the time, cost, and annoyance? In most cases, the answer is probably ‘No’. Here are a few suggestions for fixing squeaky hardwood floors that could save you time, cost, and annoyance. 

What Causes Squeaky Hardwood Floors?

Although the tendency is to blame the hardwood flooring for the squeaking, it is not always the culprit. Quite often the noise is caused by subfloor, fasteners, or joists.

  • Expansion and Contraction. Although wood does not expand and contract as much as metal or vinyl, it does grow and shrink with temperature changes and humidity changes. Most manufacturers recommend that new hardwood is brought into the house and left to sit for a time to let it become acclimatized to the building. But even that cannot account for seasonal changes. In many parts of North America, when autumn arrives, the heat gets turned up and the humidity goes down–in effect drying and shrinking hardwood floor. Spring weather will see less heat and more humidity. All of this can cause hardwood floor boards to rub against each other, rub against the subfloor, or move up and down on the fasteners.
  • Inadequate Subfloor. Hardwood floor manufacturers recommend a subfloor of at least 3/4″ tongue and groove plywood. Nothing thinner and not OSB. Thinner plywood and OSB do not have the strength, or thickness required for proper fastening. And may not remain rigid enough to support the floor.
  • Loose or Warped Subfloor. Not only does the hardwood flooring react to temperature and humidity fluctuations–most every building member will be affected. Maybe not in a daily noticeable way, but over time nails get loose, and glues and other bonding can fail. Building codes vary from location to location, but in many places, and for many years, subfloors are supposed to be glued and screwed to the floor joists. When done properly, this system about eliminates loose subfloor. Of course, many, many houses lived in today were not built that way. Subfloor–specially thin subfloor or OSB can warp if heavy loads sit on them for long periods of time. People do not, or cannot always set the legs of that 7-shelf book case directly on a joist.
  • Fasteners. Newer hardwood flooring is usually installed using cleated nails, or staples with very good holding power. Years ago hardwood floor was often held down with finishing nails–smooth, spiral, or ring. As flooring, subfloor, and joist expand and contract, fasteners can become loose. The flooring or subfloor or both can then slide up and down on the nails–squeaking and/or making a cracking noise.
  • Inadequate Floor Joists. Most floor joists in recent years have been a minimum of 2 x 10 material or an engineered joist. Building standards were not always adhered to back in the ‘good old days’. I have been in houses with 2 x 6 joists with such long spans that the floor sags when walked on. A floor system that has been bouncing for years will almost always cause flooring and subflooring to get loose.
  • Improper Installation. Floor joists are always supposed to be installed ‘crown up’. (Most wooden framing will have slight bends in it.) If a few joists were installed ‘crown down’, your subfloor will not be level to start with. And as the wood dries out over time the crowning may increase, stressing and loosening fasteners. Your floor may end up with a ‘wavy’ look and feel. (Sometimes bad luck happens. The Framing Fairy will produce a rogue piece of wood with a knot or grain that warps or cracks in a significant manner–and really mess up the flooring.)

Note: As an example of wood expansion, I had a 9 foot long 2 x 4 wall stud in my garage warp and bow the wall out over 2 inches. Not a tough repair in the garage, but could be a little more annoying in the basement.

How to Fix a Squeaky Hardwood Floor From Above

Almost all board squeaking will be caused by expansion and contraction. Try to isolate the noise enough to determine the source. Before you fix it, you need to find it. Spend some time walking around the room with the squeaks. If there is more than one, or it seems to squeak over a larger area, take a roll of green painters tape and mark out the areas making the noise.

Lubricate the Hardwood Flooring

This may sound like a goofy suggestion, but it is actually a very effective way to eliminate the noise of hardwood floor boards creaking against each other. Start by lubricating the squeaky areas. If the noise disappears, no further action is required. Here are a few options.

  • Dry Silicone Lubricant. Dry silicone spray is my favorite option–not only for hardwood floors, but windows, door hinges and handles, water sprinkler, etc. It sprays out wet, but when the accelerant evaporates you are left with a long-lasting silicone film wherever it has been used. Use the straw and apply directly–and sparingly– into the cracks. (This stuff is as slick as goose poop on wet grass. Over spraying onto the floor is never a good idea.) 

3M Silicone Lubricant - Dry Version, 08897, 8.5 oz

  • Graphite Powder. Any good graphite will reduce, if not eliminate, flooring squeaks. But Maximum Velocity Premium Graphite Powder is very fine and comes with a needle nose applicator which will get most of it between the hardwood boards. If you have ever used graphite on hinges, you know it works great, and leaves black smudges. So applying it exactly where it is needed on the floor will save some continuous cleaning. It works great but the potential for a mess gets it listed second.
  • Talcum Powder/Baby Powder. Sprinkling Talcum powder into the gaps between floor boards will also work quite well to silence the noise. The biggest problem is the none of the containers I have seen offer pinpoint application. You end up having to sprinkle it along the gaps, sweep it into the crack, then vacuum it to clean up–without removing all of the powder from where it is needed. Seems like a finicky fix. 
  • WD-40. Some people–including flooring installers–swear that WD-40 is the greatest fix for hardwood floor squeaks. The right type of can will come with a straw, allowing you to spray into the gaps between boards. Then it will dry out. (I only included WD-40 in the list because some people who should know suggest it works well. I am not a fan and have never used it for floors–or much of anything else.)

Note: Quite often lubricating the hardwood is next to impossible. This is usually the case when the hardwood is older than the president and has enough wax, or oil finish, or Varathane on it to look like glass plate. You just cannot get anything into the cracks.

cleaning squeaky hardwood floor

Fasten the Hardwood to the Subfloor

In a perfect world, all hardwood flooring would be installed perpendicular to the floor joists. Then you could be sure of hitting a joist when screwing down your flooring. This is not a perfect world. In a lot of instances, you are trying to tighten the subfloor to the floor joists by screwing through the flooring with as little damage as possible. To be successful, you require a stud finder, a Squeak N0 More #3232 Counter Sink Kit, and a Coconix Floor and Furniture Repair Kit.

Once you have found the floor joists closest to your squeak, or squeaks, follow the instructions for the Squeak No More kit to screw down your floor. The screws that come with the kit are made with heads that can be broken off after installation to leave a small countersunk screw hole. Use as many as you need to attach the subfloor solidly to the floor joists, then fill and finish all holes with the Coconix kit. You should be able to match virtually any color and grain pattern.

Note: Most stud finders work best up to a 1 1/2″ depth, which could be the thickness of your flooring and subfloor. Which could make finding the floor joist a little tough. If you are not convinced the stud finder is giving you the correct information, one of these option could work for you.

  • Tapping. If you have a good ear for sound differences, tap the floor with a hammer. (Do not hit your hardwood with the hammer. Have a wooden block to tap.) When you are over a floor joist, it will sound flat or dead. Non-joist spaces have a deeper, hollow sound.
  • Measuring. Floor vents are usually attached to a floor joist. Pull off the cover to find the joist. Then you can measure across the floor to find the rest of the joists.
  • Technology. The Walabot DY2PBCGL01 Stud Finder claims to ‘see’ four inches into walls/floors when used with an Android smart phone. Having never used one, and being a technological dinosaur, I have no further opinion.

Zircon Stud Finder A200 Pro/DIY 3 in 1 MultiScanner; Stud/DeepScan Modes Detect Edges/Center of Wood/Metal Studs to 1 ½” Metal Mode Lath & Plaster Alerts Presence of Live, Unshielded AC US Model

How to Fix a Squeaky Hardwood Floor From Below

If the ceiling in the room below your hardwood floor is finished in drywall, and you are not planning to remove it, then ‘Fixing From Below’ is probably not an option.

But if you are planning to do the repairs from below, you will need to have someone walk on the floor while you watch and listen from below. Mark the noisy areas with green painters tape. (Note: It is a good idea to have the ‘walker’ also mark the floor above.)

Brace Twisted Floor Joists

Floor joists can twist as they dry. As they twist, a gap can be created between joist and subfloor. The subfloor will slide up and down on the nails causing that squeaking noise. Twisted joists can be repaired by installing 2 x 2 cross bracing (bridging) between joists. Bridging is also accomplished by using solid wood blocks (of the same dimension as the joists) between joists. Proper bridging of floor joists helps reduce bounce which can eventually cause fasteners to become loose. For more detailed information please see Floor Joist Blocking and Bridging: Complete Guide.

After getting your joists straightened, there is a good chance you will still have to fasten the subfloor tight to the joist using the Squeak No More Counter Sink Kit and the method described above because there could still be a space that allows the subfloor to move on the nails.

Shim the Subfloor

Occasionally, subfloor will warp–usually when it gets wet, or due to expansion and contraction. This could create small spaces between joist and subfloor that allow subfloor to move on the fasteners and cause squeaks. It is fairly easy to cure this problem by inserting MaxTite Pine Wood Shims (available in different quantities) between subfloor and joist in affected areas. Insert one shim from each side to maintain level.

Snug is good–one small hammer tap. (Driving the shims in tight will likely force the subfloor up and compound your problems.) When you are satisfied with the fit, and have eliminated the sound (shims installed and someone walking on floor), mark them, remove them, apply PL400, and re-install them. Once the glue is dry, cut excess shims off and squeeze PL400 between the subfloor and joist–on each side of shims.


Repair Warped or Broken Joists

Floor joists warp for a variety of reasons.

If they warp upwards you end up with a hump in your floor–sometimes large enough to pull nails in neighboring joists, which will then squeak. Fixing this problem will require cutting the joist at the warp and attaching the same size piece of lumber to the joist. Ideally, the new piece will be full length so it sits on the walls and/or beams holding all the other joists. Failing that, make it as long as possible and install it against the cut joist with the cut about in the middle. Hold it in place with a screw at each end.

With your 250 lb. brother-in-law standing on the humped floor to level it off, nail the two pieces together. Three nails–top, center, bottom–every 12″ from end to end of the new piece. (Do not screw the pieces together. Screws do not have the same shear strength as nails.) An air powered framing nailer will make the job quicker and easier. Use the Squeak No More Counter Sink Kit and the method described above to attach the subfloor to the new joist repair.

Note: If you are not comfortable cutting your floor joist, consider hiring a professional.

Sometimes floor joists will warp downwards creating a sag in the floor or pulling subfloor nails out of that joist and causing a squeak. This situation can be remedied using shims as described above. Or by attaching another piece of material to the joist that will support the subfloor at that location. Cut you section of wood long enough to extend past the sag by at least one foot in each direction. (Straightest piece of wood you can find. Preferably the same dimension as the floor joists.) Apply PL400 to the top edge, push it tight to the subfloor and warped joist; then screw or nail it to the existing joist.

Note: If the sag has pulled the subfloor and floor down with it, you may be able to re-level it by prying the subfloor up from the warped joist. I would give it a try unless the subfloor is glued and screwed down. Trying to loosen glued and screwed without wrecking things is virtually impossible.

End Notes

If you are going to install a new hardwood flooring, here are a few suggestions that could help stop the squeaks early.

  • QuietWalk Plus. Soundproofing underlayment also eliminates wood on wood noise.
  • Expansion. Make sure to leave the recommended expansion spacing around the perimeter of the hardwood flooring.
  • Cleaning. Make sure the subfloor is clean. Remove drywall mud (if new construction), dirt, glue, everything. Having something create a lump under the hardwood will come back to bite you.
  • Tar Paper. Roll out tar paper on your subfloor before installing the hardwood flooring. Prevents wood on wood rubbing noise. (Best advice I got from a flooring installer before putting down my first hardwood floor.)

Terry Schutz

I have worked as a contractor, sales person, and business owner in the construction industry for over three decades--mostly in home renovations and also as a home builder. I have been married to the same wife for 46 years. We have 3 children and 4 granddaughters. I have also been writing semi-professionally for about 20 years--construction articles, personal stories, and politically incorrect social commentary.

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