I have a squeak in the floor. Saw tons of post and videos on fixing this. One question I was not clear on, which was one option, was to drill up into the floor to secure it.
For example, from the basement, drill up into the sub floor and floorboards? I assume you dno't want to go further than 1 3/4"? Is this truly a real option, to drill straight up with a 1 1/2" deck screw?
This is not my main option and I am not looking to recap on all the other things I can do, this was a way to just ask if this one option out of the 5 I looked at was a good option to consider?
I most likely will be doing a sister joist and adhesive underneath. But just wanted to see if drilling up into the floor was a real option that works?

 

It depends what the squeak is being caused by. Typically, it is a nail that fastens the subfloor to the joist. They are hard to fix because pulling the nail is the only real fix, and there is no getting to the nail unless you can locate it exactly with a helper by holding a rubber hose to your ear like a stethoscope. Then make a precision cut with an oscillating multitool with a carbide metal blade to cut the nail.

If the squeak is between joists, then you know it is a flooring nail that goes into the subfloor, and the floor is flexing when you walk on it, most likely caused by a dip in the subfloor. In that case, it's possible that a few well placed deck screws from the bottom up would suck it down tight, but you would need to be careful that you didnt drill or screw right up through the surface of the floor. Dont laugh... it's a fine line between the screw being too short to catch and too long. You would want to determine exactly how thick your subfloor is and know how thick your wood floor is. It would likely work best if you would drill a pilot hole and use a countersink for your screws.

I assume you have a wood floor on top of your subfloor since you mentioned "floor boards".

I would also add that depending on the age of the house you might be fighting an uphill battle. Older houses used bright nails that get loose and diagonal planks for subfloor and they are notorious for squeaks. Particle board is also a horrible product for subfloor squeaks. Typically anyone who works on those types of floors knows that the best course is to rip out the particle board and replace it. It's that bad.

 

What do you have on the floors, carpet, wood?

Fix depends on the material!

 

Yes it is engineered hardwood flooring on a sub-floor. Looking from underneath I can see diagonal planks.
The engineered woods is 2 years old, this was laid onto leveled sub-floor, that sub-floor is on-top of those diagonal planks.
I already have a few holes that go up behind the fridge for water access. I can measure the thickness.
I could consider a few screws from the bottom up. I will also be using a sister joist as the squeak is coming from the joist. I think if I secure a side joist up next to the main joist as seen in multiple DIY videos, the sub-floor will sit firmly on the sister joist rather than sinking.
So maybe a few short screws and a new sister joist with some adhesive. I will also look into from the top down using thinned out pva to seep downward as a third options.
Thanks for the help.

 

Yeah if its diagonal planks I'd say it's a 99% chance that it's a nail in one of the joists and nothing you can do will fix it unless you can find and cut the nail as mentioned above. Squeeks like that need to be fixed from above before the floor and new subfloor is put down.

 

Ouch, you have three layers of wood which any one (including fastners) can produce a squeak!

All I can say, in my wood floors, I isolate the spot, drill a 5/32 hole, sink a 6D finish nail and putty up the hole. For the most part it works!