Insulation - Fibreglass or Polystyrene Foam?

[comstech]

Hi everyone, I have purchased a Jumbo van which I want to insulate but am not sure on using fibreglass batts or polystyrene foam
My thoughts are if I use fibreglass the vibrations from the road could turn it in to dust which could build up in the bottom of the panels and get wet causing rust

So my question is for the people that have insulated there vans what did you use and if it was fibreglass batts have you ever done a rebuild and what condition was the batts in.

Also any other suggestions would be good

Thanks

[TIMO]

Hi everyone, I have purchased a Jumbo van which I want to insulate but am not sure on using fibreglass batts or polystyrene foam
My thoughts are if I use fibreglass the vibrations from the road could turn it in to dust which could build up in the bottom of the panels and get wet causing rust

So my question is for the people that have insulated there vans what did you use and if it was fibreglass batts have you ever done a rebuild and what condition was the batts in.

Also any other suggestions would be good

Thanks

Sheet material is always a better choice as the wont hold moisture , you could always try that aliminium foil stuff thats 10mm thick but its expensive,,, caravans still use polystyrene as its been the favoured choice for years,, or you could go kingspan .

[jolly olly]

I have used kingspan and it's lasting very well, checked it this summer when I redid the ply lining and the foil bubble stuff on the roof and it's worked a treat.

[comstech]

So no one has used rock wool or similar with success?

For the floor will just putting foam in the gaps be enough then put a thin ply sheet down for the floow

[jolly olly]

I did read somewhere someone used rock wool and plastic sheeting as a vapor barrier then the plied over the top, i personally don't like this method or using expanding foam assuming by foam you mean the expanding stuff.

[TIMO]

Apart from rockwool being totally sheite .... it doesnt have no where near the R value of polystyrene but the creme de,la creme is kingspan by far .

[trannydenz]

i agree with timo, rockwool is shite, itches you to bits and will rot your van from the inside out, polystyrene sheets are better and easier to work with,

[snakey]

I used 25mm polystyrene sheet from B&Q and Wickes on my build. Doubled up on the deeper sections and broken into smallish pieces and dropped into the air spaces in all the strengthening supports.

[Aardvark]

From my experience with building steel yachts...........I wouldn't (couldn't) use fibreglas insulation. I was once called in to run some new wiring behind the cabin roof lining panels and when I took the panels off I found there was ordinary fibreglass insulation behind them and it was totally saturated. So heavy with water that it literally fell out. The metal surface behind it was in a pretty rusty state. This boat had never been near the water at the time, it was still being finished off! I hate the fibreglass stuff in all its forms because of the itch factor. I have always used either slab polystyrene foam or the silver multi-layer high tech stuff that is very easy to install in odd shaped areas. With my current van, LWB high top, I went with an idea they use in production steel boats, reefer vans, and lots of industrial installations. Sprayed on foam. It comes in a kit with a bottle, some plastic hose, and a mini spray gun. You can spray it on to any clean dry surface and it hardens of in 10-15 minutes. Its just like the stuff they used to spray on the surface of hot water cylinders in houses. When its cured it leaves a hard impervious surface skin that doesn't allow water to soak in and rot the metal behind. In my case it also stopped a lot of the rattles and booming noise I had when running empty. May be a little expensive to do a large area but its good stuff. If you must use fibreglass wool types then the key is to stop any damp air getting to the surface of the metal. That's where the condensation (and hence the rust) begins. Put on a good thick coat of any sort of paint to protect the metal, then add your insulation, then try to exclude all air movement into the cavity. That means either some sort of continuous vapor barrier or at least careful taping of all joints before you put on your final decorative lining. Back in the 70's I did a Beford CF and used vermiculite loose fill insulation. Poured in from a high point in each area and after it had settled down, added enough to top up each cavity. When you shut the side loader (on hinges, not sliders) it sounded like closing a vault. Warm and toasty when camping in Norfolk at New Years Eve.

[comstech]

Thanks for all the replied, the answers I got about the fibreglass rockwool type was sort of as expected and I will be going with sheet polystyrene foam

[Homersaysdoh]

Foil board I.e. Celotex, Xtratherm,, ecotherm, Kingspan, has roughly double the insulation properties of polystyrene so 25mm of foil board is equal to 50mm polystyrene, as it's foiled both sides it's also more moisture resistant and can be joined with duct tape, and is easier to cut and shape. Fibreglass can bunch up, best place to buy is a builders merchant, or if you want small bits builders often have off cuts to dump, hope this help.

[andycaca]

just to add to this, if you want to use expanding foam to fill gaps, its wise to use "closed cell" expanding foam. this is waterrepellent and wont rot your van from the inside out (apparently).

i am going to use this type of foam to fill the joining gaps and little bits and pieces inbetween the celotex board

[Davesbackbone]

Hi all, im about to start my insulation process, what shall i put on the bare metal if using polystirien board/sheet and then ply??

[comstech]

Do you mean bare metal or painted metal?
If bare put on a all in one rust proof paint / primer....

[Davesbackbone]

Sorry, i mean painted metal the inside of the van as they come, then i was led to believe that applying flashing tape on first then sticking the polystyrene onto that followed by ply, ive read about the spray stuff but is expensive and i dont like the idea of the wool type loft insulation due to fibres and getting wet, i wast too keen on polystyrene sheets as ive read its noisey as it squeeks when driving and the natural flex of the van when cornering and braking, just need a pointer where to start as im desperate to get cracking but there is so many different ways, im on a bit of a tightish budget but i understand this is probs the most important bit, any help apreciated
Thanks