Greetings all.
I would like to pose a question to those well versed in re-purposing.

I have very old herringbone oak floors (100 years+) with over 6mm of wear layers that were glued on to T&G pine using rabbit skin glue.
After a century of exposure and abandonment, there is now glue-line separation.
The ancient sub-floors in the house had to come out due to centuries of dry rot, so a new concrete sub-floor with heated floors (wet system) was installed.
I would like to retain these original and storied floors, as they add a lot of character to the very large rooms.

My 2 questions are as follows;
1. Can these wear layers be glued onto a new, multi-ply backing material. If so, does it have to go thru a special high pressure process.

2. Is it possible to glue dimensionally stable multi-plysheets of backing material to the heated sub-floor and then glue the reclaimed wear layer to the backing material, or does the backing need to be the exact size of the individual herringbone pieces.

I have attached a couple of pictures.
Thank you in advance.

https://www.dropbox.com/s/hisiu5ot8dyna ... r.jpg?dl=0
https://www.dropbox.com/s/ini5fvhjswxzs ... .jpeg?dl=0

You can glue plywood to the concrete. Once the concrete is covered with the exterior grade plywood you will be able to glue the pieces of flooring in your pattern. There may be a problem with compatibility with glues on the market today, since the bottom of your flooring has the animal glue residue. Hide glue is not used to fasten flooring, anymore. Latex, acrylic, or moisture cure poly-urethane types of glue are commonly used to hold wood to a concrete or plywood surface. The adhesives are made to adhere to bare wood. The bottom of your pieces may need to be sanded individually to remove remaining glue to get to bare wood to ensure good adhesion.
Looks like you have some beautiful flooring. Store the flooring in controlled environment during preparation of your concrete sub-floor. Radiant heated floors ought to be very comfortable.

Pete,
Thank you for your reply.
The ceilings are 12 ft, so underfloor heating was a no brainer
Yes, the plan is to sand the glue off the boards to obtain maximum adhesion.

In terms of ply, you mentioned exterior ply. Any reason for this?
I was wondering if high-end interior dimensionally stable multi-ply would be more suited to prevent expansion, and if smaller sized ply sheets (4x4) would make any difference.

Thank you again.

Exterior plywood is stable and resistant to delamination when it gets damp.
Smaller sheets are easier to handle. I adjust a saw so that the blade almost goes through the sheet and cut in a grid pattern so the plywood has better contact as it is glued down.

Thank you.