Slats over Mesh

A question was posed to me about my build, and I am going to pose it to the forum...
The trailer I have to work with has stained slats over mesh.
(Someone borrowed and improved on what was there before. Pressure treated wood)
A friend asked me if I couldn't just leave them in place? Build my box insert with some type of water proofing in between the bottom of the box insert and the top of the slats.
And if so, (thinking and typing at the same time
) Could I seal in between the slats to decrease water coming through? Having a hmmm moment
Opinions/Thought?
The trailer I have to work with has stained slats over mesh.
(Someone borrowed and improved on what was there before. Pressure treated wood)
A friend asked me if I couldn't just leave them in place? Build my box insert with some type of water proofing in between the bottom of the box insert and the top of the slats.
And if so, (thinking and typing at the same time


Opinions/Thought?