Boler floor

[BarbaraQ]

Hi, I'm Barbara and I'm new to Fiberglass RV.
I need to replace a portion of my floor in front of the door where it is rotting. We pulled up the vinyl tiles, found rotting plywood underneath, and then it was stuffed with dirt in between the plywood and fiberglass bottom.
Is this normal??
I am buying new treated plywood, but what to I put under the plywood, in between the plywood and fiberglass bottom?
Thank you for any suggestions you can give me. This is my first DIY repair.
Barbara

[FRED SMAILES]

The wood needs to be fiberglassed into the floor.
Without seeing your problem reads like the glass is factory so placing mat and resin between the wood and old glass floor will secure it.
Remove the rot, shape the new wood to fit, glass it in place and finish top of wood in the manner it was originally.

[BarbaraQ]

Thank you for the response, I really appreciate it.
My co-worker suggested that what I initially thought was soil, was actually just the rotted plywood. He's right.... on closer inspection that's what it is.
I have it all out now, and I have the measurements to buy treated plywood, but I'm not sure what you mean when you say mat and resin, and glass it to the floor.
I'm not a very techy person, and really hope this is something I can do myself with help from my children if I need it.
Thanks again!
Barbara

[FRED SMAILES]

Although I haven't seen your project I would assume that the rotted plywood was laminated into place with fiberglass. This process would have been used to add the strength of the wood to the trailer.
Search YouTube for the process of 'laminating fglass to plywood' to understand.