Insulation for a panel van

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  • What’s everybody use to insulate a smallish van , VW transporter sized or maybe the smaller Fiat Scudo type vans . Maybe a future project in mind . There’s got to be better options than expanded polystyrene, my last canal boat had that and it wasn’t brilliant .

  • Hi BigBear , rock wool was the insulation in our first canal boat . The boat was second hand so whoever fitted it out chose the insulation . It’s so long ago I can’t remember any problems but I’ve no memory of being cold .

    Did you use a vapour barrier ?

    I’ve got a boat cabin to do first so insulation is top of my list . Ideally I need something rigid and easy to cut .

  • Hi Madcat. No vapour barrier all I did was paint the glass black inside then 50mm of Rockwool then clad with 8mm boards. Apart from windows the bus was already carpeted up the walls so I covered the carpet with 19mm polystyrene cos I had loads. If you need something rigid try Kingspan, but I found the rockwool easy to cut with a snap blade knife fully extending the blade. I bought a pack of it in pre cut sheets rather than on a roll, easier to deal with I reckon.

  • My experience with Kingspan or polystyrene is the creaking when on the move. Rockwool is brilliant but always use a vapour barrier and always use battens to screw or pin wall and roof panels onto otherwise there will be cold spots, (little pimples of moisture show it up where the cold comes through from the outer skin).

    This experience is from building narrow boats including my own and at least five living vans as well as all of my campervans including the LT35 I have now.

  • Thanks everybody . I haven’t thought of creaking but as any van I have is less than silent in other ways it might not be a problem . It’s a popular solution for narrowboats .

    I was cold sometimes in the boat with polystyrene insulation, if the fire wasn’t kept ticking over well at night and it was freezing out .

    I’ve seen the cold spot thing in action on a boat and will be doing my best not too have any .

  • Anybody tried the newer sound deadening and self adhesive stuff some people on YouTube have used.?

    Boat I’ve decide will be easiest fo me to use the solid panel type plus spray foam out of cans for the joins , gaps etc .

    I’m just waiting for the boatyard to do the repair on the cabin which involves a riveted seam then I can paint before insulating . Lining out will be t and g , easier to handle in a small space .

  • I'm sorry to dis-agree but with rockwool I would always use semi- permeable membrane such as the new stuff for under tiles and slates.

    If its semi permeable whats the point in using it?

    You already have a vapour barrier in a van, the body. If you fit another one inside youll trap moisture between the two and thats when youll get problems. Leave it open and breathable, yes it may get damp or wet but it will also then dry out again with the heat and air flow that you add to your van whilst living in it.

  • As I understand it, the difference in temperature between the outside of the metal and the inside of the metal causes condensation which transfers itself to the insulation. The water vapour produced by humans, kettles etc is stopped from going through the semi-permeable layer, (as long as it's the right way round) and the water vapour from the condensation in the insulation goes through the semi-permeable one way barrier and with the human produced vapour is dissipated through vents and open windows.

    Hope that helps and sorry if I offended you.

    It is very important that it is fitted the correct way round.

    So it's metal, insulation, semi-permeable barrier, cladding and then there's no condensation or black mould as long as there is adequate ventilation in the accommodation.

  • No offence taken, and thanks for reply.

    I understand now where "semi permeable" comes in, maybe badly named by the manufacturer. If it works in the way you describe then perhaps a better name/description would be one way barrier? My understanding of semi permeable in your first reply was semi waterproof hence the question what's the point.

    Think we are pretty much on the same page as regarding airflow and ventilation being the key to reducing moisture and mould.

    A lot of the FB group "experts" recommend plastic sheeting or bubble foil completely sealed as a vapour barrier. Obviously you cannot get it completely airtight or 100% coverage so moisture will get through, and IMO without the required ventilation behind it moisture and mould will build up and corrosion will occur.

    You haven't changed my mind about using a barrier, but I'll look out for some if that semi permeable stuff in skips during the course of my rooting and will try it on a small scale comparing it to nothing. Always willing to learn something new....

  • In my opinion the very best place for foil backed bubblewrap insulation is a skip. Ive used it on my van roof interior (which is fibreglass) and despite it being sealed airtight ive removed some due to condensation running down the van sides and found its detached from the roof and its had pools of water and coated with mould underneath.

    Admittedly it was used as a rush insulation job and not my ideal choice but ive had no end of issues with it.Ive also used it in a few areas in my trailer and got mildew because of it where i had non before so ill ever use the stuff again.

    Ive removed it all now and when i get round to it im lining van and any trailer surfaces with sheepswool insulation as its natural (I personally dont want synthetic materials or chemical based insulations or glues in my living space) its naturally water repellent and naturally fireproof to B standard.

    Whatever you use though will have its own drawbacks.

  • There will always be drawbacks to any choice of insulation as RT points out.

    There are always multiple variables to consider ie: time, cost, skills, number of available hands, choice of heating and cooling and ventilation, the shape and material assets/deficits of the structure... etc, etc.

    I've only experience of steel vans and little time, patience, skill and hands with which to apply insulation.

    Based on the previous paragraph I'd currently recommend looking at multilayered foil and wadding options offered for apx £70 to £100 for 15 Square metres....

    Requires batons, staples, aluminium tape and grip fill or the like but would do the job and leave breathing space except where the inescapable sandwiching of materials is required.

    Price, speed and ease of application works out OK for many different scenarios.

  • I found a YouTube video ( from Coombe Valley Campers I think ) showing the use of some modern looking foil faced stuff and a wadding type product .

    Looks like there’s a lot of options .

    Zendaze , I think that must be the the system you suggested .

  • Not an answer to insulation, but short term if you are too cold in bed at night, slipping on some socks and wearing a beany makes a huge amount of difference.

    Builders foil aka sarking used on the roofs if new house construction placed underneath a floor covering will reflect some radiant heat. Ask nicely for a piece at a building site.

  • As years in the building trade, we use vapour barriers, however me being a tight sod id probo in a van not bother, I recon you need a vapour barrier is probo a must with rockwool or sheep wool, it stops the warm air striking the cold gaps that form with ill fitting rockwool, this causes condensation, of heat and breath of you in the van, Kingspan is a little more forgiving, as it kind of is a vapor check in a crappy way itself, proving u use foil tape to tape the joints, I was all air gaps and the like many moons ago but as iam getting older I think sod it rooms at a premium in a van,

    The confusion is with vapour barriers, theres a few types.

    Visqueen or pvc sheeting, not really the best but does the job and is a fire hazard, its really designed for damp barriers under floors.

    Breathable roofing felt, works good, remember to put it correct way around it only breathes one way.

    Fancy breathable vapur barriers I used one for lineing a wine store, I thought it was overpriced but it was good stuff,

    muti foils I know sod all about these but there expensive but they take up less space and I belive work well.

  • breathable vapour barriers, way to go !.

    What's the thinking behind this? Just curious. If it's breathable then surely the vapour is going to get through and therefore a bit pointless using it isn't it? Over the years I've done my vans insulation in all the ways suggested. I still don't know what's best. :D What I do know is that both my buses were lined with carpet and 9mm ply with rockwool stuck in the cavity. Neither had problems with condensation pooling as it was able to escape through the gaps in the lining. I've just about finished our latest van and seeing as we were a bit flush for a change I went down the silver bubble wrap, dacron, bubble wrap line. I'm now worried that the dreaded condensation is going to eat it's way through the metal from the inside, it's a Sprinter! :D

  • basicly breathable works like a gore tex jacket, or a fancy water jacket, your body allows steam to escape so you don't sweat, but the outside layer stops penetrating damp (rain), if you wore a plastic sheet you would be dry but you would sweat, in builing terms years ago ventilation was required as old bitumen felt and plastic barriers used to condensate.

    So back on topic vapour barriers allow steam to esacape but stop any water getting back in in the form of condensation or water build up. where as if you do nothing you get condensation forming. I deally air gaps work the best in building as you get a naturally vented cavity similar to a modern house.

    I used to see problems in building/roofing where the cosy wrap touched the felt, ie no air gap, the cosy used to get wet,

    I think breathblle felt has revolutionesed building but sometimes it is over kill.

    terminology terms in building there are many

    Rockwool or isowool cavity bats are desgined for full fill cavity walls there soaked in a water proof liquid in the factory and should in theory stop penetrating damp and consation, but only if they are fitted correctly woth no gaps.

    isowool ecostic is desgined for internal walls to stop mainly sound but are quite good insultorsa as well but useless at preventing damp.

    cosy wrap is designed for flat lofts and settles if used upright or on slopes causing gaps

    rule of thumb, if its wool it generally needs a moisture barrier.

    Kingspan or pir unsulation can be fitted on a risk wik no barrier providing no gaps good fit and use tape on all the joints preventing heat loss through gaps. but as pointed out itl probo squeak.

  • As I understand it, ( i'm no expert), the rockwool or whatever you use insulates the inside of the van from the outside heat or cold, therefore there should be little or no condensation formed on the metal skin because the metal is cold on both sides. (The rockwool insulates the inside of the van from cold and heat from the outside and the heat from the inside from escaping to the outside).

    The remaining problem is that humans produce a great amount of moisture through breathing and sweating and cooking and that moisture has to go somewhere, that's the reason that good ventilation is so necessary however it certainly is a balancing act and sometimes there is a surplus of moisture.

    The semi-permeable layer allows the walls to breathe, (it allows air through but not moisture).

    Sooooo not strictly necessary but a sort of extra insurance to moisture penetration either way.

    One other thing I do is be sure the ceiling slightly overlaps the vertical cladding so on the off chance that there was any moisture inside it, ( leaking sky light or vent) , then the moisture stays outside the living accommodation.

    Also, as I've said before, always wooden batten before attaching the internal cladding to stop cold channels to the inside through attaching cladding directly to the metal exterior, noticeable as small globs of moisture on the inside of the van.

    Hope this helps although it's only what I do and may be utter nonsense even though it has always worked on all my boats, vans and trailers including my current LT35, ( Sprinter look alike but different engine).