3.5 ton horse box rotten floor

[ollski]

Hi I need to replace the floor on my 3.5 ton horse box. I was intending on cutting out the rotten section and then replacing it with a bit of mild steel plate. Do I need to weld the new floor in or is it ok to rivet it to the cross members?. From there I was thinking of painting the whole floor in a bitumen paint inside and out and relining with 18mm phenolic plyboard and then rubber floor. Would you put some drains in then?. Thanks

[ollski]

Actually thinking about it I think I'll just put a 600mm wide 3mm plate over the top, rivet the old floor to it and then paint and treat and lay a new 18mm buffalo board floor on top.

[bazjude2998]

If the floor has rusted from the top down I would have concerns for the chassis sections below.
With respect if you don't know what is deemed as a structural part of the vehicle I would seek advice.MOT don't like pop rivets

[ollski]

Thanks but its a conversion so this old tin floor is not structural like in a van. The cross members are solid.