Black Tank Galv Box

[TomW]

My Airstream, before I bought it, sat many years with leaks which wasted the bathroom floor, and the galvanized box which supports the black water tank. I have completed building a new galvanized box, repaired cracks to the black water tank, and removed the bathroom floor up to the first seam (roughly 4X8 foot area).

Since my floor had turned to mulch, I have no idea of what many things looked, like how close the galvanized box was to the decking. There appeared to be the remnants of a [foam?] seal between the box, and the decking. Also, once holes are cut for the waste drain valve, and the gray water line (I do not have a gray tank), it does not look like there will be a whole lot of support for the weight of the toilet.

I am now ready to cut new decking for the bath area. Does anyone happen to have pictures of what the decking, with holes, is supposed to look like. If not, has anyone done a similar procedure to a rear bath Airstream I could PM to get more insight?

Thanks,
Tom