For serious sound insulation and or sealing the floor pan in the rear of a van goto auto shop for 'sound deadener/bitumen paint?' could be $$ and best sprayed on. Its not designed to even out the hi/lows just reduce noise and seal, use timber packers for that if support for the ply floor is needed.

If your putting ply down with rubber backed carpet or rubber mat I wouldnt bother, it should be enough to reduce road noise if fixed down, just put 'Fish oil' on the floor pan first then your ~8mm ply/carpet floor. This will seal the pan and help inhibit rust.

Re Van floors not having uniform surface, the high ribs should be at the same height, thats where you want to tech screw your ply down, just check below first and use the right length screw to do the job. Besides its the plys job to provide the uniform surface. Depending on the thickness of the ply it will flex in one direction more than the other, so run it perpendicular to the ribs to reduce flex. Idea is to use the lightest ply to do the job, no point lugging extra dead weight around save that for your gear.

If your routing cabling below the floor make sure you don't pinch/crush it.

cheers

Windsurfing kit is a good sound deadener.The more i put in my van the quieter it is.
Seariously i wouldn't go putting down a false floor.Just creates a place for sand and moisture to sit.Better off spraying some sound deadner on (the stuff that dries hard).and have a light mat in there.Then you can just hose it out every now and then.Fish oil is ok but it attracts sand....

Hi guys,
thanks for the all the help

miguel

for a cheep job go back to bunnings and get some packers, there 10mmx2,400x1,200 chip board for about $5 each, and use some rubber flooring, i have 5ply on mine, they allso have craftwod or mdf they use them on there palets for protection during transportation so they sell them cheep rather than shiping them back

I am also needing to do the floor of my van , being a car stereo nut i know of a product called DYNAMAT its used to reduce road noise and absorb vibration ,

its like a sheet of aly foil with a black tar like stuff on the back so it sticks to the surface and stays there.

it will not let any road noise thru and because its stuck to the floor it should protect it from rust aswell.

as for the floor, make it in 2 or 3 pieces separated laterally so you can remove them for washing and rust inspection.

the only downside i can see with this is that its quite expensive at about $500 for the back floor of a lwb hiace its also a bit on the heavy side because it is rather dense.

but i guess if it stops the rust then its cheap insurance for your van

Hi Miguel,

Check out some Aussie made automotive sound absorbing materials at the following link:

www.spec-net.com.au/pyrotek/sound.htm

I used a similar material many years ago to insulate a highly modified and noisy Ford Transit van. I used it on the floor under the carpet and on both sides of the firewall and engine cover. Made a big difference noise wise and didn't stink like some of the bitumen based matting I've tried.

Also try auto accessory shops or auto upholstery shops, they may have similar products.

Hi guys

I end up going to a local rubber and foam store where they recommend me some type of rubber/foam/mat kind da stuff (which I don’t know the name). They ensure that it’s good for noise and temperature insulation, tough not the best if water gets in. But since I am putting a 3mm layer of plywood on top of that plus a marine carpet on top of everything I hope little water reaches the mat.. Not being perfect it should be good for some years. The good point is that it was rather cheap 39.95sm.
Anyway thanks for all the advices

Miguel