Hello,
In a few weeks, we are having a prefinished hickory floor installed in our house. Our current floor is an old heart pine, and as the house is old, it has no subfloor, which is common in our area of Houston. So, we would like to use our current pine floor as a subfloor, underneath the new hickory.
I have a couple of questions. What should be between the pine floor and the hickory? The installer is just planning to use kraft paper in between, but I was wondering what you guys would recommend.
Also, the current flooring, which is 3 1/4" wide, runs from the front of the house to the back of the house. The new hickory is 5" wide, and we would prefer that it run the same direction, but intuition tells me that we're asking for trouble by doing that. What do you think? Would the floor feel more stable and be less noisy if we run the boards perpendicular to the current ones?
Thanks so much!

What is underneath the pine... a crawl space? We need to know that first.

Flooring installed on top of existing strip or plank floors should be ran on a diagonal or perpendicular, not parallel.

Has anyone informed you that 5" solid Hickory is problematic at best, even with ideal situations?

There is a crawl space underneath the pine.
What is problematic about 5" hickory? Hadn't read or heard that; curious to know what you think!
Thanks-

Solid hickory flooring, especially in wider planks, tends to expand and contract more than other, more stable wood species. In your case, I would recommend installing a layer of 3/8" CDX plywood over your existing pine floors IF you wish to run the new flooring in the same direction, parallel to the old. Then, I would consider gluing and nailing, which has been shown to help plank flooring move less. Also, your crawl space under your house must be absolutely dry year round and should be well vented. A layer of black 6 mil polyethylene should cover the entire ground/dirt under the house as a moisture vapor retarder. The hickory flooring and subfloor should be within 2% points as measured with a moisture meter. Since your flooring is prefinished, I would bet it comes with detailed installation instructions. You should have the installer follow those to a "t". Plus, follow the maintenance and precaution notes for the home owner to a "t". Failure to follow directions is usually the #1 cause of floor failures.