Came across an old back seat from a fiesta today which had a thin (18g) steel back with ribs pressed into it. I've cut this down and plan to use it for the forward part of the floor pan -as shown here. The rest (under the seat etc.) will be paneled in 'normal' steel with the seat mountes on tubes. Any thoughts? (The photo is 'flipped' hence the ceiling at the bottom - sorry if it makes you feel sick!!!!! )
Rescued attachment DSCF1000.jpg

how thick are your box/tubes?
I assume there will be some cross-members?

If they are more then 1.8 mm i would use aluminium panels. Around 1.2-1.5 mm

personally I like ally checkplate with the ribs ground off where they contact the frame tubes would contact it. the thin stuff is about 2mm thick and could be fixed to the tubes with rivits and sikaflex this would be consistant with the minimilist design paramaters (no floor mats required)

I would not use it. In course of time it can becomes rusty. Use some ally checkplate like niceperson709 says. Or some flate ally panels. On my car I used 2mm ally for the floor.

Greets Roy.

If painted/looked after properly that could do nicely under the seats to stop the floor "popping" as some find this really annoying.

I would say cracking idea, nice to stop the floor popping in and out!

Not the best quality steel so paint it well, but good idea!

As 'the book' advocates use of the donor roof for the floorpan - this has to be better!

I used steel for mine.

But I actually put swages or ribs into the steel sheet with a machine at college.

Floor certainly doesn't pop with normal usage!

Cheers,
James