Massive condensation behind roof liner

RidersofRohan said:
Presumably it’s not just PVC’s that might have this problem. The cab area of most Mhs will need a lot of work for a converter to do as the commercial van cabs will start life with minimal insulation.
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Thats an interesting comment as a common comment is regarding the cab area as being cold or cooler, I thought it may be just the windows but now you mention it there could be other causes.
 
Had a similar experience when installing a 4G MIMO aerial in our PVC (a 2014 Wildax Europa). I installed it in the cab roof over the driver's seat. Not sure about current models, but in ours everywhere is well insulated apart from the cab roof. This just has a thin felt-type material stuck to the metal. When installing the aerial, I noticed that the material had come unstuck from the metal. And bare metal equals instant condensation (and plenty of it if the temperature dips), so it was pretty wet! After installing the aerial, I stuck the material back onto the metal and it is now dry again.
 
Thank you everyone for your replies and thoughts.

The roof insulation in our van comprises
24 mm of rigid foam
3 mm ply
3 mm head liner

However as we have 3 large roof vents on a 5.4m PVC the overall value of having insulation must be questionable.

The roof insulation is not bonded to the metal roof of the van although foam panels have been stuck down in other areas such as around windows and over the cab but it is by no means complete or continuous. The whole headliner can't be removed as it was probably installed BEFORE the toilet/shower was fitted and due to the ribs and panel arrangements it will be very difficult to retro fit additional stuck down insulation but it is a task to add to my projects list.

For some perspective consider that in terms of volume there can only be about half an eggcup full of actual water present.

What I found interesting about this situation was that until large sections of roof liner were removed there was no evidence of any condensation and so I wonder how many other makes of van may similarly affected with the owners unaware.

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I insulate with Thinsulate in all of the accessible cavities but I'm well aware that there are many nooks and crannies that get cold and cannot be reached to insulate. Whilst we use the camper (high roof LWB VW T6) as an everyday vehicle it's these inaccessible places that get damp and concern me. When we sleep in the van in cold weather we always try to drive the next day with the maximum flow, not necessarily heat, from the vehicle heater to get maximum air through the body. The VW has air outlets with flap valves in the lower rear corners exiting behind the rear bumper.
 
Mark and Mindy said:
Thank you everyone for your replies and thoughts.

The roof insulation in our van comprises
24 mm of rigid foam
3 mm ply
3 mm head liner

However as we have 3 large roof vents on a 5.4m PVC the overall value of having insulation must be questionable.

The roof insulation is not bonded to the metal roof of the van although foam panels have been stuck down in other areas such as around windows and over the cab but it is by no means complete or continuous. The whole headliner can't be removed as it was probably installed BEFORE the toilet/shower was fitted and due to the ribs and panel arrangements it will be very difficult to retro fit additional stuck down insulation but it is a task to add to my projects list.

For some perspective consider that in terms of volume there can only be about half an eggcup full of actual water present.

What I found interesting about this situation was that until large sections of roof liner were removed there was no evidence of any condensation and so I wonder how many other makes of van may similarly affected with the owners unaware.
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Its interesting and food for thought, on one side its a shock to find the condensation as you described and suspect you are right other manufacturers may be the same it also may be that its within 'design limits' but the manufacturer need to state this after all they claim to test and provide winterised vehicles including the PVC's
 
So we've just rubbished loads of PVCs, you have to get the insulation correct at time of build it is no good trying to rectify after all the other stuff has been put in.

Must say in our Murvi when we had it, used loads in winter and never noticed anything.

In fact I took some insulation out and it was in perfect condition behind, wall panels though not above cab.

Murvi use cheap 2 bit loft insulation as well which was surprising. But no issue with it at all, DBK could maybe confirm?
 
CazPaul said:
So we've just rubbished loads of PVCs, you have to get the insulation correct at time of build it is no good trying to rectify after all the other stuff has been put in.

Must say in our Murvi when we had it, used loads in winter and never noticed anything.

In fact I took some insulation out and it was in perfect condition behind, wall panels though not above cab.

Murvi use cheap 2 bit loft insulation as well which was surprising. But no issue with it at all, DBK could maybe confirm?
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My experience also and I'm fairly familiar with the "roof space" of our van so to speak.

Although loose glass insulation is sniffed at by home converters from what I've read on here, in combination with a non-porous and well fitted lining it seems to work. I think this is because it more or less prevents the air circulating between the cold outer skin and the warmer inner bits. It isn't airtight but it stops air movement sufficiently to prevent condensation.
 
DBK said:
My experience also and I'm fairly familiar with the "roof space" of our van so to speak.

Although loose glass insulation is sniffed at by home converters from what I've read on here, in combination with a non-porous and well fitted lining it seems to work. I think this is because it more or less prevents the air circulating between the cold outer skin and the warmer inner bits. It isn't airtight but it stops air movement sufficiently to prevent condensation.
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Yes agree, the insulation, although not the best to use by far was like brand new after 10 years, as was the walls behind.

So the question is, which PVC converters DO build them right then, apart from Murvi who seem to.

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Well we have a Hymer a class absolutely no insulation in the doors, and our previous Rapido a class had absolutely no insulation in the over head cover above the drop down bed.
I know this for a fact as I have dismantled both for one reason or another.
 
CazPaul said:
Very poor from Hymer, that's the problem with building a van, it's the bits you can't see that are the most important.

One of the reasons I was considering designing my own PVC van.
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When I built my van the most important job was getting it properly insulated all else came second /later.
 
Chris51 said:
When I built my van the most important job was getting it properly insulated all else came second /later.
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Yes to do it properly you have to spend time getting it right, before anything goes in.
 
Very pleased we decided to go with insulation stuck to all metal surfaces but as a general observation, this is not only a problem with vans, it happens in houses too! We had a brand new house in the eighties, very well insulated, except... that the built in wardrobe didn't get as warm as the room and condensation formed on the outside wall: my leather boots went mouldy! The wall wasn't even particularly cold, just colder than the moisture laden warm air that got in every time we opened the wardrobe. Warm air holds a lot of moisture.
 
Most PVCs are likely to have this issue to some extent at least somewhere. Unless it's a self
build like the one pictured, I can't see any commercial converter covering everything like that. I've only had PVCs, two of them converted by myself and although I did make an effort, I simply couldn't access many places. I've never had a problem with condensation.

One thing I would add is that other than some Mercedes built before 2004, and old VWs (especially the wide square 90s models) which rusted badly, most vans have galvanised bodies, or at least have anti-rust treatment inside and out, so internal rust is less of a problem. Their outsides are directly subjected to volumes rain and lots of cold weather and generally last well. It is mostly the likelihood of internal discomfort that could be a problem, but as I have said I've never had a problem like that.

The first van had suspended roof lining as is the case with virtually all cars. This doesn't seem to be a problem on cars, though of course they're not often used for sleeping and cooking. The second van had directly-applied lining felt, which stayed stuck, and was just fine. My present one (AT Trigano 670) is poorly insulated, if at all. I've insulated in those places I can reach, such as the sliding door and inside cupboards, but again, have had no problems. I've never taken the roof lining off to inspect, but would not be surprised if it is not insulated.

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After reading this article about the lack of insulation in some of the “ supposedly “ top of the market PVC campers I had a thought about our Auto Trail V Line ( 635 SE ).
Shortly after taking delivery we went off to the Netherlands and experienced so very hot weather. The rear doors were getting extremely warm inside. On our return home I removed the rear panels, they had printed on the backs that they were insulation panels. The insulation that Auto Trail had also fitted was a fairly thick sticky backed foam, however it had been stuck over the top of wiring in several places and was not stuck to the actual outer metal and there were some areas behind strengthening panels that must have been difficult to get at in a hurry. I ordered some from, I think it was CAK, I then secured it , with difficulty, to where there were gaps. As the summer went we felt more comfortable after that
I also managed to find a couple of other areas, including inside the side door, again stuck over wiring. The rest of what I could get at was pretty good.
Today I have taken the overcab area, where we keep our sleeping bags, we do use our van throughout the year, to bits, expecting to find what all the other contributors have, damp/wet. No the roof is nicely dry and the same foam insulation stuck to the roof. I’v now got to put the lining and surrounds back together, but at least I’v now got piece of mind.
The actual ceiling/roof throughout the camper is as well insulated as any coach build we have had in 25 years of motorhoming. Well done Auto Trail.
 
Ye all should have a listen to Greg on YT...
Actual heating / insulation expert :)
 
Steve and Denise said:
Well we have a Hymer a class absolutely no insulation in the doors, and our previous Rapido a class had absolutely no insulation in the over head cover above the drop down bed.
I know this for a fact as I have dismantled both for one reason or another.
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I had to drop the roof lining on my Rapido A Class (2010) to reseal the Antenna - plenty of insulation in mine.

1A845C89-E0A6-462D-91BD-35B2930524A4.jpeg
 
Well ours had none whatsoever 2011 tag Rapido but still a great van with very few minor problems.

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Ooo er, you've got me thinking-worried now.

2006 E745 Bessacarr , I've always thought the headliner for the over cab bed seems to be mighty thin and hollow. Mind you the outer skin is plastic/ gel coat fibre glass, so maybe-just maybe, less condensation?

So has anyone had experience with a similar vehicle, the liner over the front cab bed on a Bessaccarr/ before I take mine to pieces you might save me tons of work please.
 
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I expect there are many motorhomes like Hymer and Carthago A Class where the walls and roofs are built from insulated panels, where no additional insulation is needed. However if I had something with thin metal motor panels I would want to find some additional insulation bonded to the internal surfaces.
 
I wish I had not dismantled the overcab storage area in our V Line as it is harder to get it all back together so that it looks factory fit. I have the lights off at the moment trying to rewire the 230v/12v/tv socket unit under the roof locker behind the overcab storage , I had taken down the locker to gain access to the screws holding up the facia panel across the storage area.
The wife has gone out for the day with her friends, good job it’s tipping down with rain, I could have done with some help in holding the roof locker in place whilst I got the screws in. I think I’ll report the credit card stolen !
I have just watched Henry Walpole video of the disgusting build of his Hymer, some of our Funsters have taken Auto Trail to task regarding leaky coach builds and I fully understand the frustration this causes but in my case I am satisfied with our particular PVS.
Auto Trail owned by the giant Tigano group also build the Tribute PVS range, Benimar PVS campers and a couple of other manufacturers PVS models, it would be interesting to see if they have the cab roof areas insulated as well, perhaps that is one of the reasons the V Line range is a bit more expensive.

BernieT
 
This is unusual, a thread extolling the virtues of British build quality in comparison with our European friends.
I always thought European vans specialised in insulation and winterising their vans.
 
Just a thought.

I had a very minor leak from a roof-light, it was minor and only leaked when it rained (obviously) so difficult to spot. The water evaporated, but gave condensation on any exposed metal, anywhere in the van. OK, normal habitation causes moisture from breath etc, but to a lesser extent. There could be a leak somewhere putting moisture into the air, which is then condensing anywhere that it can (eg your metal roof).

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I also have a HymerCar Ayers Rock so was quite worried by reading the OP. I went to check and over the cab is a plastic liner not fabric so I guess they know that condensation happens in that area. I am not skilled enough to remove it to check but I might mention to the dealer at the next visit. I have the lifting roof and I do follow the makers instructions to open the roof to air it and the van every three weeks and the humidity levels seem OK. The van stays warm enough in the Winter but I guess the mattress and folded canvas act as good insulation in the roof area. I think a cheap humidity meter might be on my Christmas list just in case.
 
This couple have an adria twin



They are insulating the doors with Armourflex, they are assuming that there is no condensation in the roof but if the doors are then the roof probably is I suspect this is an industry wide issue whether it is something to worry about is something else
 

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