Carpentry and Woodworking - "Springy" Hardwood Floor

I have a oak floor that causes furniture to rattle when you walk on a section of it. I have inspected the subfloor from the basement and cannot see any thing that may be the cause of this condition. I have been told that there is a space between the sub flor and the oak floor which causes this "springy" condition. The recommendation was to either screw the subfloor into the oak floor from the basement side or screw the oak floor down to the subfloor from the fininsh oak side. I was told that there are screws that have a removable head that can be used so the screw can be hidden by filling it with a plug.
The floor joist are 2x10 for about a 12ft span. This springy condition has increased over time. Any suggestions on a fix?

Thanks!


Paul

The screws are one choice and a nail gun is another. Going from the top is better and you really want the screws or the nails to go through the floor and subfloor, into the joists.

Before you do any of it, look for signs of the joists moving. It's rare but it can happen.

Thanks for tip on the floor joist moving. I am assuming they would either twist or roll? If this is the case, would installing more x bracing between the joist be a possible action?

Paul

Look at the ends of the joists first. You'll be able to tell if they shifted. You can even it them with a hammer to see if the move or if they are rotted. Don't be a afraid to give them a good shot.

While I agree with what has been said, I find it difficult to believe the subflooring is separating from the oak flooring. Is it 3/4" oak and was it installed with flooring staples at an angle? If so, my thinking is the subflooring and flooring as a unit is separating from the joisting. I know you have looked, but take a few hardwood shims with you down there and see if you can drive them between the subflooring and joist. If so, you may be able to fix it from underneath. Just another two cents worth.

Chandler,
The home was built in the 60's so I am assuming the same as you about the oak floor being installed the correct way. Can I purchase hardwood shims at a Home Depot or Lowes or local lumber yard?

Paul

Did you look to see if there is a place to install the shims and if they are really needed?

I would go under there and have someone walk on the floor are in question, keeping an eye on the positioning of the joists and the spacing between the joists and subflooring. You will be able to see the movement and thusly the remedy. Unless you cut them yourself, a mobile home moving company may be able to supply you with a few. If you cut them youself, they need to be cut with the grain, not across it for strength.

I got some shims and had someone walk on the floor to locate any movement. I was not able to see any movement, but I did put in a few shims where there was a space between the joist and the subfloor. But, it did not have any effect on the condition.
In the spaces between the boards that make up the subfloor, I was able to see what looks like particle board over the boards. I also noticed some white residue and some plaster type material that had seeped through the spaces between the boards.
I am wondering if this is floor leveling compound?
If I try to screw the floor down from the finished oak side, what would be the best way to locate the joists so I scew into them?

Joists are usually 16 inches on center. Check it from the cellar, then measure from the wall on the main floor.