I've just replaced my suburban floor plywood. There should be images in my profile. After much deliberation I had to opt for cutting out and then replacing in two sections as I have no power in my garage to remove spot welds from the side trim and not enough headroom to raise the body high enough to slide the timber out from underneath.
For ply I chose Birch ply as it has almost twice the amount of ply layers than the original and is a much more dense timber (even in todays standards). The birch was 12mm with a more decorative iroko deck slats at 8mm offset over the joint and bonded using marine glues and sealants.
The result I am very pleased with and it isn't going anywhere anytime soon. It weighs quite a lot but weight = strength, no?
I hope this helps.
This method means the job is not as scary as you might think.
