Squeaky Subfloors

[shubox56]

In addition to repairing my bathroom floors, I've also ripped out all of the old carpet on the second floor. Before installing new carpet, I need to address a very squeaky subfloor issue. In the master bedroom and vanity area, it's grossly squeaky. I'm thinking some of this is a lousy construction decades ago and the subsequent settling and sagging of the floor over the years.

I don't have access to the floor from underneath to add bracing so I'm not sure what is the best way to approach the issue? Just add screws between the nails? Or pull the nails in the bad spots and replace with screws? The subfloor is 3/4", what size screw would be best? And would a good zinc coated deck screw be a good choice?

This issue affects numerous spots, somewhat widespread in nature. It drives me crazy and I just can't fathom the idea of living with it for another day.

Thanks as always!

 

[Mark Brown]

This will greatly depend on what the squeaks are but yeah, start with some screws into the joists. I usually use 1 1/4 screws, mostly because they are the cheapest that will fit in my pam gun, but idealy you might want something a little longer, 1.5 or 1.75 would get you there for certain.
If that does not help, it could be joist hangers squeaking, might as well forget all about that because it is a lot of work. Sometimes over time the joints in plywood swell or shift (re: sagging) if that is the case you can add gapping by running a circular saw down through them.
If none of that fixes anything, it could be wall plates moving on the sub-floor, you can shim under those....
really as you might have guessed "squeaks" is a rather broad category that will take a little more determination to fix.... we need to localize it.

For the record though, you could not pay me enough money to pull nails just to rescrew sheets..... unless that one pesky nail missed the joist and is rubbing on it, then i would lose my mind lol

One more point, construction is just as lousy now as it was umpteen years ago except now we lie to people and tell them the garbage they buy is "engineered"
Engineered joists, there is a crock.. or how about "engineered" OSB, yeah, someone engineered that compressed shake into a flat panel. The only engineering i really see succeeding is the engineering of the consumers minds to gobble up that gook.

 

[shubox56]

Dang Mark, very good read.

While kneeled, I can replicate the squeak by pushing down the subfloor. The floor is definitely not true (sags/uneven), so the nails in various areas have failed. I believe the squeak is the nail(s) against the joist, but like you're indicating, the problem could be that in combination with other things. I'll start with screws and see where that takes me.

Let's assume that SOME of the squeaks are eliminated, but not all --- OR --- the eliminated squeaks slowly return. To lessen the mental torture, is there a best-in-class sound deadening underlayment that could be used under LVP and carpet? There are many out there, but it's difficult to filter through the marketing BS.

Thanks again for taking the time to write. Much appreciated.

 

[highup]

Are the nails all in a straight line or are they random?

 

[highup]

I don't think there's a sound deadener out there that would dampen the squeak. Much better off to get rid of the problem if possible and it usually is.

 

[shubox56]

Are the nails all in a straight line or are they random?

Straight lines. Not random.

 

[Mark Brown]

So now we are on to something. If its localized like that and out in the field of the room, just screw it off and that will likely solve your problem.

 

[highup]

If the rows of nails are 16" apart this will be easy. Drive some screws along that same line an inch or two away from the nails.
I use this kind. Our local true value hardware carries this kind in a bin for around $6.50 per pound.
Hillman Power Pro No. 8 x 2 in. L Star Flat Head Ceramic Coated Premium Deck Screws 5 lb. 767 - Ace Hardware
They drive in so much easier that a Phillips head screw. You can't strip out the head on torch head screws.

 

[shubox56]

Thank you, Highup. I have an ace 2 miles from the house, I'll make a run.

Looks like the carpenter who repaired my bathroom subfloor (patch) pulled a nail. It's a 2.25" ring grove type. So I was thinking 1.75" or longer screws, I just wasn't sure what is TOO long.

 

[Mark Brown]

I love that somehow they call it a "star" head screw but it is a Torx, wtf is America's problem with using the proper screw head names. They are proprietary and specific. Same goes for Robertson and Phillips.... i just don't understand. Then again this is a personal problem because i fight with my wife about it all the time.... She says silly things like a Square bit, then i tell here it is a Robertson bit, then she ask me why it matters, then i say because that is what it is, then i get told that makes no sense, then i say it makes perfect sense but you do not care to know, then she says but it IS a square, then i say that IS a Robertson head, back to "it makes no sense", then i have to go and say stupid things like she is willfully ignorant and there are only 2 that are common and would it be so hard to remember two things? We have two girls, you don't call them the short one and the tall one.... then i sleep on the couch.
But just so we are clear, they are Torx. Hence the T-20 Designation on the bit

 

[shubox56]

Funny Mark. It could be disagreements with wives that resulted in my TWO divorces.

 

[Mark Brown]

.... hmmmm, I may wish to reconsider my arguments

 

[Dan]

One more point, construction is just as lousy now as it was umpteen years ago except now we lie to people and tell them the garbage they buy is "engineered"
Engineered joists, there is a crock.. or how about "engineered" OSB, yeah, someone engineered that compressed shake into a flat panel. The only engineering i really see succeeding is the engineering of the consumers minds to gobble up that gook.

Amen, Brother!

 

[highup]

How about a four cornered screw head, Mark?
I once worked for someone that was a member of the 3M company. She and her husband had divorced and at the ages 15 and 17 she reinherited her children a boy and a girl, both spoiled.
The older one, the boy, was given a Honda 250R three wheeler by his mom. At that time, those were the hot ticket. Those were the good machines that everybody wanted so they can show off.
As I was installing carpet he came in and asked if he could borrow a screwdriver. I asked, what kind?
He replied, the one that looks kind of like an X. I handed him my Philips screwdriver and he was quite content.

 

[Mark Brown]

How about a four cornered screw head, Mark?
I once worked for someone that was a member of the 3M company. She and her husband had divorced and it ages 15 and 17 she reinherited her children boy and a girl both spoiled.
The old one, the boy was given a Honda 250R three wheeler. At the time those were the hot ticket that was a good stuff everybody wanted.
As I was installing carpet he came in and asked if he could borrow a screwdriver. I asked, what time?
Purified the oneness kind of like an X. I handed in my Philips screwdriver and he was quite content.

I am either high or you are because i cannot decipher that for the life of me, I got Divorce, 3m, Honda and Phillips

 

[highup]

I forgot to get to my point. The kid was disassembling the rear axle and had removed the wheels which were a nice shiny gold color. He was painting the wheels Ford engine blue. His mechanical abilities was like a .05 on a scale of 1 to 10.

 

[highup]

A square headed screw has four corners Mark......
Robertson's come in many shades.

 

[highup]

Mark I'm using the microphone instead of typing. I am reading everything perfectly and then after it's posted my words all get high.
What's with this microphone's spelling correction? Why don't they have this fixed by now? Hell it ought to be able to read my mind and type what I'm thinking at this time and date. Man they need to get up to speed.
...... Or I need to start typing on my tiny smartphone keyboard.
I'll go back and see if I can fix some words so I look smarter.

 

[highup]

Okay Mark go back and re-read what I wrote. See if it makes a little bit more sense.

 

[Mark Brown]

Okay Mark go back and re-read what I wrote. See if it makes a little bit more sense.

I must be coming down