Floor ply/insulation questions

[Frosty3006]

Hi guys. Been spending all day today stripping rust from my mk6 SWB floor. Brushed on a thick coat of red oxide and will top coat tommorow then fill any small screw holes using silkaflex.

Couple of questions regarding my next steps as I hope to never have to come back and redo old work in the future!

I know there is a wealth of info online regarding campers and insulation but any specific awnsers would be great for guys that have been there and done it.

I was originally going to use battens and 25mm celotex, then something like 9 or 12mm ply. But im thinking that if I lay down my battens they will sit either too high or too low in the dips in the floor which will mean the ply will have gaps in certain areas. Possibly desierable for trapping air?

If i was to cut strips and lay them onto the lower sections of the floor, then celotex, then board again I dont know how I feel about the timber strips being laid straight onto the metal work. Maybe im being over cautious.....Im just wanting to make sure moisture dosnt get in at all!!

Secondly.... Vapour barrier sheeting before plying...is this pointless on the floor?

Sorry for the same old questions! But Im just unsure about sticking timber straight onto the floor!

[Jambofive]

how much rust did you have to remove i would always have painted a rust convertor/inhibitor on first before your red oxide its helps alot at keeping rust at bay ,vapour barrier is a good idea but ventilation is always the most important thing

[Frosty3006]

Hello, thanks for your reply!

There wasnt much on the main seciton of the floor. But around the wheel arches and along some of the wheel arch seems there was quite a bit of surface rust. No holes mind.
I used a drill and wire bruch attachment and got it as best I could, wiped with heavy duty cleaner and then painted. Hope this will be ok! I did think after I should have applied a rust inhibitor....but It was raining and I needed to get something onto the bare metal whilst I had the chance! Recon this will come back through soon?

I plan to stick a roof vent in Main thing is getting the floor done so I can just use the van again for a few weeks! Any methods you prefere for the floor?

Thanks

[Jambofive]

i would just lay that 2 layers of silver bubble paper then 12mm ply i think thats enough unless you plan using it on staying in middle of winter . some waxoil wouldnt go a miss aswell

[Frosty3006]

Thanks mate. Once I glue the foil down, shall I then just silkaflex the ply on top? Don't want to screw into the floor again! Equally I want the floor nice an solid and not moving around

[Jambofive]

i would pot rivet ply down lets your put paint in drill holes i do this with my work vans never had floor move and we abuse them alot. unless u can get nice tight fit then pin it down round the edges with your wall board ,i am a big fan of sikaflex but if your board starts to warp for some reason dont tink sikaflex would stop it .