11

Two nails in my hardwood flooring keep popping up:

enter image description here

I have knocked them back in, but because of a bit of flex in the floor, they work their way back up. What should I do about them? Is it best to just pull them?

2
  • If you don't want screws - which I wouldn't - why not try bigger nails? Why not use dedicated planking nails, which those in the picture do not seem to be? Jul 11 at 22:36
  • From the looks of that floor, it's topnailed hardwood (I'm not an expert, but that's what ours look like) - really, really common 100 years ago here on the west coast of the US, and the nails aren't anything special. How often do they come up? I've always just kept a nailset (what @knowitall called a nail sinker) in the hardware drawer and tap them down occasionally. It's just part of maintaining an older house. Jul 11 at 23:42

8 Answers 8

25

Use lost-head screws. These have heads small enough that they will pull down into the surface so you can cover them with a dab of filler.

There are many types, for different purposes, but all have this tiny head that will pull down below floor level. Often they use torx or square drivers so they won't cam out when driving. Drive them at an angle for even better pull resistance.

enter image description here

From comments
This may be another of those terms that doesn't cross the Atlantic well. If I search "lost head screws" I get a lot of hits, all in the UK. If I search "finishing screws" I also get a lot of hits, but a high percentage of them are in the US.
Interestingly, if I search "lost head nails" vs "finishing nails" in the UK I get the 'correct' nail [ie the one I thought I was looking for] for lost head, but I get the wrong nail for finishing.

3
  • 1
    In the US these are often called "finish screws".
    – FreeMan
    Jul 11 at 11:48
  • Never heard of lost-head; there is a Lost-Tite brand though. Trim/finish screws is a much more common name.
    – MonkeyZeus
    Jul 11 at 13:54
  • I found these sold as "trim screws" in my local hardware store. They worked a treat. I was able to use the same nail holes, as the screws are significantly wider than the nails. This is also my only complaint about this fix -- the screws have caused some swelling around the heads. But it's not very noticeable, and this was a quick and easy fix. Aug 8 at 20:26
6

I'd pull them out and see if the floor squeaks or flexes. Maybe you don't need them and can fill or ignore the holes.

Otherwise, replace them with ring shank or spiral shank type nails...as suggested here:

How do I keep nails from pulling up on my hardwood floors?

4
  • Terrible answer, pull the nails out and see if you need them?? At best this 100% will result in a squeaky floor, and at worst will result in more nails popping.... keep pulling them out and you wont have any left! Jul 11 at 22:55
  • If the floor doesn't squeak or flex resulting in more nails popping out...then....you....don't...need....them. Jul 12 at 4:39
  • Yea but my point is what you describe is never going to happen in the real world. You remove nails from a wooden floor board you are 100% going to introduce extra additional flex, which in turn will lead to additional force on the remaining nails, making them more likely to pop, resulting in more squeaky floorboards, and you're back to a worse position than you started in. Jul 15 at 0:55
  • OK. In your world every single nail in every piece of wood is critical. Sure. Got it. Jul 15 at 3:40
6

"Two nails in my hardwood flooring keep popping up: I have knocked them back in, but because of a bit of flex in the floor, they work their way back up. What should I do about them?"

Civil engineering answer:

The problem is not the nails, it is the floor flexing. The friction between the nails and the wooden restraint structure has been overcome by the force of the flooring pulling against the nails. Fix the underlying cause of flexural movement and nails will not be an issue ever again.

Using screw threaded fixings will not relieve the stresses causing the problem but may actually cause damage over a longer period.

Injecting a low viscosity epoxy filler, that will harden, through the nail holes into the underlying flexural space may be the best route in solving the flex.

2
  • 8
    All floors flex, once the house is old enough. Trying to follow this advice in an old Victorian pile would result in having to glue-lam the entire building. I get where you're coming from, but sometimes all you need is a couple of screws & ignore that the entire building has shifted at least an inch, & in non-contiguous directions, since it was built.
    – Tetsujin
    Jul 10 at 16:41
  • 2
    Coming from a woodworking background, the wood fibers no longer have any sort of strength, or possibly any significant contact with the nails anymore, so the nails are useless, unless you fill the holes. I've used my finger to push nails like this back into place, which shows how useless it is to keep putting them back in. The OP either needs a bigger nail or a screw. Even epoxies won't stand up over time in the small of amounts to fill the gap between the nail and the wood. And trying to epoxy one spot will only cause other nails to pop out as the wood expands in other directions. Jul 11 at 19:06
2

How do I fix popped nails in hardwood floors?

Note: this answer is intentionally literal instead of pragmatic.

  1. Pull the nails straight up out of the floor
  2. Tape off the floor surrounding the hole
    • Blue painter's tape is ideal
  3. Put some wood glue in the hole
  4. Tap a toothpick or three in the holes
    • Make sure to get the toothpick below the hardwood surface
    • If a toothpick it sticking out then cut it off with a knife
  5. Hammer the nails back into place while the glue is wet
    • Do this while the glue is wet because wood glue likes pressure and if you wait till the glue dries then you'll just break the glue bond between all of the wood
    • Ideally you would use a trim nail punch to set the nails about 1mm below the surface
  6. Remove the tape and wipe up the excess wood glue with a damp sponge/cloth/towel while it's still wet
  7. Try not to step on that floor board for at least 24 hours while the wood glue cures
7
  • 1
    "Wood glue really likes pressure". That's a long held myth, because strength tests show that wood glue actually likes there to be a lot of wood glue to be strong. Squeezing out all the glue and not having enough of it to make a bond are both problems with pressure. Not exactly scientific, but a really good example of someone making an effort to answer the "is more pressure better" is this video. youtube.com/watch?v=14Mkc63EpMQ Jul 11 at 19:21
  • 1
    @computercarguy thanks, edited.
    – MonkeyZeus
    Jul 11 at 19:30
  • I'm not even sure if that's enough of an edit. Wood glue often needs pressure to keep the pieces from moving around while it's wet, but one of the tests Matthias did in the video was to keep the wood pieces separated from each other, effectively having no pressure on the joint or the glue, and it was the strongest joint. Jul 11 at 19:50
  • @computercarguy I'm inclined to believe that a manufacturer wants you to succeed with their product. Please review the Clamping Pressure Guidelines
    – MonkeyZeus
    Jul 11 at 20:06
  • Normally I would follow manufacturer recommendations, but those clamping pressures are insane. This article says "snug" is good enough. woodmagazine.com/tool-reviews/clamps-clamping/… Even a company that sells high end, high pressure clamps for woodworking says you don't need that much pressure. Their recommendation is "Tighten until you see the glue ooze a bit." ponyjorgensen.com/blogs/clamping-pressure-techniques I'm pretty sure none of the hand clamps I use go beyond 50 psi, and even my bar clamps probably don't go over 100 psi. Jul 11 at 20:29
2

Hammering them back in same hole wont hold

Hammer the nails at 10-30 dgr angle to drive the nails, that will stop them from coming out. That might take some practice.

Use a nail sinker tool, so to drive the nails just below surface and not to keep banging/damaging on the floor.

nail

source: sears

Fill the old nail holes with wood filler

If you do not want to do all above, go to store and get longer nails.

Using glue suggestions:

Glue will not flow down the hole to the underfloor, it will mostly get soaked up at the top portion.

It will hold the nail and fool you, since it is not holding the floor to the underlayment.

Result, squeaking floor.

2
  • 1
    Would use a thin piece of wood under the hammer/crowbar to protect the floor if the nails are hard to pull up.
    – crip659
    Jul 9 at 1:25
  • The wood fibers aren't likely able to hold the nails anymore, at all, so driving them deeper will not work. I've pushed nails like this in with my finger. Pushing the nails in an extra 1/4" isn't going to keep them from popping out again. Jul 11 at 19:08
1

I'd pull them and put in a few drops of cyanoacrylate glue (AKA superglue) or epoxy in the nail hole, re-install the nails and I guarantee you won't see them pop up again! Like knowitall's suggestion to use the punches to get them slightly below the surface and fill with wood putty.

4
  • 2
    afraid the glue will not go deep enough to make nail stick to the subfloor, or is there a trick how to do it
    – Ruskes
    Jul 9 at 2:19
  • put a few drops in (or more) and use a tooth pick to drive it down further. Jul 9 at 5:00
  • 4
    "....and that's why I have a toothpick glued to my floor."
    – Sneftel
    Jul 11 at 13:16
  • Cyanoacrylate glue (AKA CA glue) cures as a crystalline which will shatter/break under stress. I almost never use it anymore because it's such a weak bond, unless it's between my fingers. You'd have better luck using standard wood glue and a screw, but then the screw would be doing more work than the wood glue to keep things together. Jul 11 at 19:12
1

Seems like no-one has mentioned pulling out and using bigger nails. If you're certain there are no pipes or wires underneath, in the joist, and the joist will take longer nails, great. Thicker nails would also do the job, same length as originals, if you're not sure. Otherwise, two or three toothpicks in the holes first will help. Or, knock the nails in at a crazy angle, avoiding the holes from where they came. Cheap and cheerful.

-2

Whaterver the method from above you are using:

Make sure there are no pipes underneath.

A freind of mine once hammered back a popping nail and ended up with an expensive plumbing work that required lifting off a whole section of a floor. Clearly a counter-productive attemept!

2
  • 1
    As an SO user, you should know that restating answers already given doesn't really fly well, and the point about plumbing below should be a comment, not an answer.
    – FreeMan
    Jul 11 at 11:16
  • As it’s currently written, your answer is unclear. Please edit to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center.
    – Community Bot
    Jul 11 at 16:49

Not the answer you're looking for? Browse other questions tagged or ask your own question.