While i am waiting for my floor to be delivered (should be in next week) i do have another question about installations. I am planning to install 4" Uptown (3/4" engineered) red oak clear (total 1200 sq feet, about 1050 sq feet on ply sub-floor and 150 sq fee on concrete).

My friend recently purchased new construction house and installed (by professional installer) unfinished HD floor: 4" R/Q solid red oak and in some rooms 4" solid Brazilian cherry. His installer recommended and installed glued and nailed down. I found some posts saying that if floor is 4" and more then glue and nail/staple is recommended.
My questions are:
- Is it really better for my type of floor to do glue and staple (on ply sub-floor)? i am not worry about financial side of it but the quality.
- What are the pluses of glue and nail/staple installation.
- What are the minuses of glue and nail/staple installation.
- If you have all time (no time constrains) relatively open budget (let say can afford a glue) and it was your own house what would you do in my case just staple or glue and staple?

Greatly appreciate your reply.

unfinished red oak engineered

There are as many opinions on this subject as there are people in the hardwood business. Here is mine: There is no need to glue down as well as nail a 4 inch board ove a sound plywood base. However, my installers always use tongue and groove glue in the end joints of any floor over 3 1/4 inch width. This can help eliminate squeaks in these end joints while still allowing the floor to react to changing humidity conditions.

Thank you dennis. I am not familiar with all terminology so i just want to make sure that i understand this correctly it means the glue applied to each side of the board (short side) but not the front and back (long side) so literally you ending up with one long (glued) plank.

Another question.
How technically you do glue and staple? I never saw any one doing that so i can only guess. Do you apply glue with trowel same way as you installing floor on concrete and then stapling down? But in this case the base of stapler will be always in glue, very messy. Or apply glue to the back of each board then how to apply? Trowel? Same way as butt buttering when doing tile work? Sounds very messy too.