Solid Hardwood, Engineered and Laminate Flooring - Sub-Floor Replacement or Addition layer

I would like to replace (or add additional layers) to the current sub-floor on on the 2nd floor of my house to reduce or elimate the flex of the floor.

The subfloor is current particle board covered with rug. Once repaired, the floor will be covered with rugs also.

I am not as concerned with the amount of work involved as much as I am with doing the right job.

As I see it it have the following choices..

1) add a layer of plywood on top of the particle board (not sure of the thinkness I should use

2) Rip up the particle board and replace the subfloor with 3/4" inch plywood.

3) Rip up the particle board and replace the subfloor with 2 layers of plywood - possibly with two 3/8" layers

Which would be the correct way to correct the problem?

It just happens I was concerned with the same dilema. However, I'm putting down a 3/4 hardwood floor. All the feed back I got said "ripup" old particle board. Came to the conclusion that was too much work! I did add 1/4 of plywood. Now I have 3/4's of plywood, 1/2 " of particle board, 1/4" of plywood, and I'm adding the 3/4 of hardwood. A little over kill but, necessary!
To answer your question, since rugs going down, 1/2-3/4 layer of plywood, laid "across" existing sub-floor should be ample. Everyone who responded to my ?'s said the same thing, 1 1/2" od sub-floor is plenty! Just take into consideration the height of your doors and door casings, etc. You may have to trim them for clearance. Good luck.:rolleyes:

Is the whole floor flexing or is it the particle board flexing between the rafters.

Real wood Floors: There's a couple of bad sqeaKS, SOUNDS LIKE particle board or plywood. If shims don't get rid of them will try "bridges" between joists. Sound good?

I believe that the flex is in the pressboard between the joists. My thought is the press board has been worn out through use.

If the whole floor has a trampoline feeling then your structure is the problem and you may have to beef up the rafters. If their is no problem with the structure and the height of the subfloor isn't a problem I would just add a 3/4" plywood on top of the particle board.

Good Luck, AL

Thanks. What would be the easiest way to beef up the rafters?

Double them up. Pull up the particle board and install a rafter of the same size next to each existing rafter and screw them together with 3" sheet rock screws staggered up and down every 12". Use a clamp to make it easy to pull them together. Unless you want to install a beam under them. What is the length and size of the rafters and the dimensions of the room?

AL