Caravan floor replacement material

Hi Andrew,

We just had a brand new off-road van built this year and had some options for the floor.
After considering the pros & cons we chose a composite floor (or sandwich panel) - i.e. two fibreglass sheets with polystyrene foam in between.
The benefits include:
(1) Lightweight - significantly lighter than ply floors.
(2) One continuous piece used - no joins necessary (so when the vinyl floor is put down you cannot see any joins)
(3) Will never rust, rot or decay.
(4) Excellent insulator - against cold frosty air in the winter or the hot air above the bitumen road buffeting underneath your van as you travel in summer.
It costs a liitle more but then everything in life thats worthwhile does.
Here is a link to a site that sells the composite sheeting (no relation).
www.vanglass.homestead.com/
Cheers,

Look up a few of the boatbuilding suppliers , they do some extremely lightweight plywoods that would be lighter than the cheque plate and much easier to work with .
Can't remember the name of the plywood offhand but I am sure you will find it.

Aluminium sheet realy is not going to give you a strength to weight ratio improvement over basic plywood, and it will be expensive in comparison.
Unless you are very particular how you do it, the combination of aluminium and steel will present a dis-similar metals issue and the corrosion that it brings.

then you have the issue of how you are going to glue the aluminium to the ply....unless you own a vac bag or a press.

The other issue with aluminium is it will be cold under foot.

There are some very funky composites available starting with foamed PVC which is a viable material ( 10mm foamed PVC is stronger than 12mm CD radiata) and stepping thru to things like astroboard and the other ultralight honeycomb sandwedges.

there are also some good light weight plywoods out there.....in the past caravans would have the cheapest waterproof ply available as the floor and that could have been radiata pine, spash pine or if you where lucky hoop....and probably structrual CD grade.

Bang for bucks its hard to beat BB HOOP, but there is lighter.

there are some light weight grades available, Giboon is popular in the boating world....last time a baught some BB exterior it was some un specified chinese timber but it was pretty light.

Giboon is about half the weight of most common CD radiata.....BUT, the lighter weight plies are often a little softer and less surface durable.

BY far the best strength to weight ratio is good quality light weight ply with fibreglass and laid up using epoxy.

10mm ply with a single sheet of 200GSM glass on each side laid up with either boat coat or west system epoxy is incredibly strong.

In a caravan you may only need to lay up the fibreglass on the underside and lay ya vinyl on the top, with or without a coat of epoxy on the top surface to seal and harden the ply.

Have a lurk on a wooden boat forum , the wooden boat section of woodworkforums.com is a start.
both the west system and boatcoat web sites have some information on fiberglass & epoxy used with plywood.
There is heaps of information on boat building with ply and epoxy on www.storerboatplans.com.

that should give you something the chew on.
cheers

Hi Andrew
I would be very weary of using aluminium sheet as flooring. You will get very high condensation the aluminium will work as heat/cold conductor. We have had extremely bad experience with roof top tent. It had encased insulated aluminium floor, and on end we glued another 5mm insulation on top. Floor was sweating and it was so bad we couldn’t sleep in cold weather there at all.
Good luck Dana

Thanks for your info so far all. I agree that given the aluminium will act as a conductor condensation will likely be a problem. I am interested in the sandwich material so will make some enquiries. Any more suggestions are welcomed.
Thanks all Andrew

You can't just use a of fiberglass foam sandwich sheet!
Any areas that are being fastened or fixed to need plywood or aluminum pads inserted when the panel is being laminated & vacuum bagged.
I would suggest using marine ply sheathed with fiberglass on the underside, or saturated with Everdure & them coated with an underbody coating.

Thanks for your input everyone.. I have narrowed it down to choosing either Marine or Form Ply and thinking 12mm with potentially more support under the floor.
Would I need to further seal the marine ply or for that matter Form Ply with an acrylic water based paint? I have no experience in using type of ply.