I am the proud owner of a maple 5/8 in hardwood floor (3.5 inches wide planks, pre-finished at the factory). It was installed 5 years ago and it still looks brand new...not a scratch...

The wood was nailed to a subfloor made of particle board covered by a vapor membrane.

I have two areas where the floor is squeaking heavily. I can feel the floor moving slightly when I walk on it and I suspect that the nails rubbing against the wood is making that loud noise...The first area is pretty small (couple of planks wide by about two feet long) and the second area is quite bigger (3 feet x 6 feet in the shape of a football)...Oh and those areas are in plain view...

I thought of removing the floor carefully and reinstall it. In order to do that I would have needed about a hundred square feet of new planks to replace the ones I would break....not an option...the color has been discontinued....

I looked at those "just under the surface breakable screws" but I would have to install so many to fix my problem that it would not look too good...

I also looked at this other "technology" (sold as a kit) where you drill a small 1/8 of an inch hole and inject wood glue using a squezable plastic container. Using this technique, you can not apply a lot of pressure so the glue does not spread that far under the floor...Could work for the small area but once again too many holes to fill in the bigger area...

I needed a tool to push the glue at a higher pressure so it spreads to a bigger area. I have found it. I will use a grease gun with a 1/16 inch needle attached to the nozzle. This will allow me to push the glue in the hole very slowly but at pressure that can go as high as 8000 psi...

I will do a test run in a closet to see how this solution behaves in real life...

My questions:

a) What do you guys think of my solution ? Any suggestions as to how to execute it ? How could I maximize the spread ? Any comments or new ideas are welcome...

b) I have seen two types of wood glue. Fast setting and slow setting. Which one would you recommend I use ?

c) I am not sure if the planks are going to "glue" to whatever surface is under there. I rather think that the glue will fill the void and prevent the planks from moving as much... Any suggestions as to what other "stuff" I could use instead of wood glue that could improve once again the spread ... Latex maybe ?

Thank you all for your help and rest assure that I will keep you posted with the results !

I suspect that the particle board may be loose to the sub-floor or the sub-floor is not fastened well to the floor joists. If the sub-floor is accessible from below you should try to add screws from below that will not penetrate the flooring surface.If it is not accessible, then locating the floor joists so you can put a nail through the finished floor into the floor joists from above should be the next thing to do. Power-cleats hardly leave a trace when nailed into a groove between strips. A little bit of colored putty will help the "hole" blend in, which is actually a little slot instead of round.
Using a power-cleat that is 2 inches long should penetrate into the floor joist.
The tough part is locating the joists.
If you need to use glue, you will need to drill a hole to inject the glue with a small syringe available at a hobby store. It won't take much pressure to get the glue into a gap between the flooring and the particle board,. Gluing the particle board down to the sub-floor would take a longer pre-drill, but the glue should flow. You may need to add weight so it contacts while the glue is setting up.
Drill a 7/sixty-fourth inch pilot hole that will be filled with color putty.