I was recently tightening the nut on a loose toilet (it was rocking) when the bolt surprisingly broke free and came up. There was no real "breaking free" feeling...it just seemed to be floating there.

What could cause this sort of thing to happen? My first thought was that the wax seal must be leaking and might have caused the floor to rot, but I have seen zero evidence of water and the tile surrounding it looks flawless. Additionally, looking up from underneath it (from the basement) I see no damage either.

My next thought is to completely remove the toilet and see what's going on, but that's an involved and crappy job, so I would appreciate any advice or wisdom you can offer.

Bolt broken free bolt side top of bolt hole floor underside of toilet

  • 8
    but that's an involved and crappy job I see what you did there. Commented Dec 8, 2021 at 2:47
  • 1
    I don't want to discourage you but in my experience that's as unfixable as a loose tooth.... now you need to build a new house ;-). Commented Dec 8, 2021 at 12:45
  • Duct tape toilet to the floor. Commented Dec 9, 2021 at 15:43
  • 1
    At least you have a very accessible exit tube. Replacing that system is actually quite doable within a day.
    – Mast
    Commented Dec 9, 2021 at 18:07

5 Answers 5


I just want to add that if the bolt head came loose because the flange broke, you can get metal rings to screw to the floor to replace or augment the existing drain hardware, without replacing the pipe bearing the flange. I had to do this once, in a concrete floor.

  • 2
    Yep...thanks for this comment. So I took the toilet off, and sure enough, one side of the flange had disintegrated for unknown reasons. I wish I had taken a photo, but I was focused. HOWEVER, because of your comment I went to Lowes ahead of removing the toilet and bought a flange repair kit (basically, the metal ring you describe) and it worked perfectly...just screwed it on top of the old flange and was done. Thank you!
    – jbwiv
    Commented Dec 9, 2021 at 21:21
  • This is a good example of the rare case where the most up-voted answer is not the correct one!
    – FreeMan
    Commented Dec 10, 2021 at 15:04
  • Glad that knowing about the flange repair kit was helpful! re "unknown reasons" I think they just rust. The bolt itself scrapes the protective coating off, so it starts disintegrating right there. Hopefully a replacement will be better made.
    – JDługosz
    Commented Dec 10, 2021 at 15:19
  • Sometimes, especially if the toilet isn't seated on the floor correctly (yes, that was intentional...) it can rock back and forth when in use and cause the flange to break or bend so that the bolts can work loose. ...Or, sometimes they just break.
    – gnicko
    Commented Dec 10, 2021 at 22:25

Before removing the toilet...

As you were tightening it, it's entirely possible that the bolt turned 90°, coming loose in the flange slot, and that's the sudden loosening you felt.

Here's an image of a toilet flange. The nifty red line/oval are my own addition showing where the bolt is supposed to go. Note that this flange image is upside down from the way it's actually installed in your floor:

toilet flange with hand-drawn red bolt
Flange image courtesy of homedepot.com. Red bolt courtesy of my excellent artistic skillz.
Hat tip to Steve Summit for suggesting inclusion of a picture.

You can see that the bolt head is oval shaped to fit through the oval hole in the toilet. It also fits through the keyhole slot in the toilet flange. My guess is that nothing at all is broken and that it's a very simple fix. Even if I'm wrong, this is a cheap, simple thing to try before you start removing things and buying parts.

  • Place the bolt down through the slot in the toilet, pushing it all the way down until it stops moving.
  • Keeping the bolt vertical and applying light pressure, carefully rotate the bolt 90° (either direction).
  • Once the oval bolt head lines up with the slot in the toilet flange, it should drop right through.
  • Carefully rotate the bolt another 90° (again, either way).
  • Pull up on the bolt.
    • It should now be caught by the flange, and should not start coming back up to hit the porcelain.
  • Assuming the bolt is caught, hold the bolt and start the nut.
    • As you tighten the nut, continue to pull up on the bolt, moving your grip as necessary, to hold the bolt in its caught position.
    • Once the bolt is snug enough, it shouldn't spin as you finalize tightening the nut.

It might be helpful to take a Sharpie™ or other marker pen and draw a line on the flat at the end of the bolt (the part that will point up as you're tightening the nut down) that is in line with the length of the oval head. This line will help you to keep track of which way the oval is facing, and it will help you to keep the bolt aligned as you're twisting, turning and tightening.

  • 5
    This is what should be tried first before any of the other answers. The only thing I would add is rotate the nut the entire length of the bolt and make sure it doesn't bind anywhere. If it does get a new bolt and nut. Commented Dec 7, 2021 at 19:54
  • 3
    As you tighten the nut, continue to pull up on the bolt... so that it doesn't turn 90 again and come out. +1
    – Mazura
    Commented Dec 8, 2021 at 11:35
  • Hopefully someone can find a picture, from above, of the way the oval-head bolt fits into the curiously-shaped slot around the edge of the flange. You're going to need to visualize this pretty well in order to get the bolt reinstalled properly, but the only way to see yours is to remove the toilet, which you don't want to do. Commented Dec 8, 2021 at 16:20
  • I did a Google image search on "toilet flange and bolt" and spotted several decent pictures, and also a youtube video. Commented Dec 8, 2021 at 16:24
  • 1
    Oh, I know exactly what they look like! My comment was for jbwiv. Your answer is exactly right, and your verbal descriptions are nicely detailed, but still, a picture versus a thousand words, and all that. :-) Commented Dec 8, 2021 at 16:26

The end of that bolt fits into a slot or keyway on the toilet flange which is attached to the floor. It's quite possible it wasn't properly installed or it's possible that the flange is damaged or something.

The only way to know is to pull the toilet and inspect what's underneath. Hopefully you just need to re-insert the bolt in the slot and be done with it.

It can seem like a daunting task but it's not that bad. Be sure to drain the toilet as best you can to make it lighter and cut down on the water mess. Remove the other bolt and disconnect the water supply. Then just pull the toilet up and away from the flange and it should be clear. The only thing other than the two bolts are weight and the wax ring.

Always replace the wax ring with a brand new one before putting the toilet back though.

enter image description hereTolet Flange

  • 22
    I would have two replacement wax rings handy during the process. The extra wax ring is in case the first attempt to "bed" the toilet goes awry. They are quite inexpensive—around $4 each.
    – wallyk
    Commented Dec 6, 2021 at 22:59
  • 10
    I would sarcastically add to turn off the water supply before disconnecting it!
    – Forward Ed
    Commented Dec 7, 2021 at 6:47
  • 5
    You probably want to flush the toilet after turning off the water supply, to empty the cistern
    – CSM
    Commented Dec 7, 2021 at 10:54
  • 10
    You can get "wax" rings now that are not actually made of wax. When I had to re-install a toilet recently I used a foam and rubber one. They cost a few bucks more than a wax ring, but they are much less messy and you don't have to worry about destroying it if you don't line the toilet up perfectly on your first attempt.
    – Robobunny
    Commented Dec 7, 2021 at 15:54
  • 9
    And here's a tip for lining up the toilet with the bolts, put plastic drinking straws on the end of each bolt, this will give a better target for positioning the toilet over them, especially if you are doing this job solo.
    – Glen Yates
    Commented Dec 7, 2021 at 19:47

Toilet bolt broke free from floor...recommendations?

You have a range of answers here, but I did want to suggest that it is possible to get your hands on a scope like this one, you probably can figure out what's going on. If you're a DIYer, a quality scope comes in handy for a variety of purposes like peering into drywall, into plumbing, through insulation, etc. I do like the answer that you can use clear silicone caulk to have the base adhere to the floor. If you do it, my advice would be to leave a portion unsealed in the back so that if for whatever reason the ring is compromised between the base and the flange, you'll see the leakage. Otherwise, it can build up belowboard and be a surprise to someone someday.

What could cause this sort of thing to happen?

Your setup looks like brand new construction (I don't see ANY corrosion) so it's either the plastic flange broke or slipped out of the notch as far as I can see. Using torque and the leverage of threads might have been enough, but with all of that wax on the head it might have slipped off. To begin with, it may have not been secured properly if someone down the chain of command was in a rush to get the job done.

  • This would do far better as a couple of comments where appropriate, not as an answer, because it doesn't actually answer the question. Also, up-vote any answers you like.
    – FreeMan
    Commented Dec 8, 2021 at 12:53
  • Thanks...definitely going to invest in a scope for go-forward projects ;-)
    – jbwiv
    Commented Dec 9, 2021 at 21:25

Just put a silicone caulk joint around the toilet base. Clean the area, put the sealant using a caulking gun, then adjust the joint with your finger using soapy water. Thereafter let it dry for two days. At least in my country the bolts are used less and less.

Edit: You need to loosen the other bolt, tilt the toilet around and clean, and then tilt the toilet around when you apply the caulk. The best is of course to remove the toilet when you do it. Another option is to let someone lift it a centimetre or so.

  • 3
    I absolutely agree, and never rely on just the bolts myself, but I'll stress to use clear silicone. It'll take the color of your flooring and virtually disappear. It's a mistake to use white or your flooring color. I'll also suggest that you not caulk the rear of the base. You want a substantial opening to show a wax ring leak if one develops.
    – isherwood
    Commented Dec 7, 2021 at 19:15
  • The last house I owned had a toilet fitted using their system (which I didn't know). It did not hold, and the toilet started leaking. Commented Dec 8, 2021 at 8:51
  • Wow...I actually downvoted you at first (fixed now) because I thought you were being sarcastic. I'm surprised folks trust caulk only to hold a toilet in place. Me, I prefer knowing it's strongly mounted to the floor ;-)
    – jbwiv
    Commented Dec 9, 2021 at 21:23
  • 1
    Caulk by itself will not hold a toilet in place, especially with a big person shifting around on the seat. Best to pull the toilet and redo as everyone suggests. Nowadays the new non-wax rings ensure that your bolts are vertical, in the proper place and orientation and stay that way. In the end, (pun intended), you need to ensure that the toilet drains directly into the waste pipe. Caulk alone won't do this.
    – DAS
    Commented Dec 10, 2021 at 5:32

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