I have purchased a ½” engineered tongue and groove wood floor product (Thomasville Jatoba) with the intention of floating it. This particular floor supports floating, glue down, and nail down. It is going on a ¾” plywood sub floor above the basement.

I really want to keep transition pieces to a minimum and planned on running the hardwood into all area’s without T-Moldings. However, I read on here in another post that one should never float it through a doorway, or any entryway smaller then 4 feet. I have attached a picture of the layout and you will see that there is a small closet doorway, a doorway going into a bathroom, and a hallway that is just short of 4 feet that connects the foyer to the large kitchen area (which is about 19 feet wide). The 5” hardwood planks would be running east-west. The manufacturer’s instruction don’t mention any maximum or minimum entry way dimensions, just that you need to have a 1/2 “ expansion gap on the width of the boards and a ¼” on the board ends.

My questions are:
Would making this into one big floating floor without T-Molding be a mistake? Should I consider nailing it down?

Can I increase the expansion joints? I have undercut the base molding and drywall and could have at least ¾ “ – 1” of expansion if it would help. I have read how important the minimum expansion gap is but I’m not clear on the ramifications of a larger expansion gap (can it lead to gapping)?

If nailing it down is a better route to go, can I still use the 3-in-1 foam underlayment?

I also want to mention what a great resource this site has been!!

Personally, I'd staple it down.

Since this floor is glued and strap clamped together when installing and not a click design, you can go through doorways, when floating.