Blisters on motorhome roof

[Greenman14]

Hi, my new Roller Team TL590, bought last November, has quite large blisters on the centre roof panel. I think these could be a problem and I'm not happy. I'll be taking the van back to the supplier but before I do I'd welcome some ideas as to the possible causes. I have to admit I never inspected the roof until August when I returned from a month in Spain and France, so they could have been there from new.

 

Hopefully I'll be able to attach a photo.

[Keithl]

Hi David,

 

Is this a fibreglass roof? If so you are likely suffering from 'Osmosis'.

 

Have a read here for some more details.. http://www.yachtsnet.co.uk/osmosis.htm or Google 'Fibreglass Osmosis', most hits will likely be for boats but the cause is the same.

 

Keith.

[Greenman14]

Thanks Keith. According to the brochure the van roof and walls are fibreglass. Photo now attached and as you see the blisters are large and have occurred over a relatively short time. The osmosis blisters seem to be smaller and take longer to appear.

 

 

David.

[AlanS]

Roller Team are part of the Trigano Group as are AutoTrail. Are you talking about a blister on the over cab unit, i.e. the fibreglass part ?

 

In the AutoTrail handbook it states that:-

" Within the first twelve months cracks and

blisters can appear in the surface of moulded

GRP components. These are cosmetic only

and have no effect on the vehicles structure.

These components can be readily repaired

using the correct procedure (please refer this

to your supplying dealer)."

 

On our previous AT Navajo we had a blister on the roof which was dealt with under warranty via our supplying dealer/AutoTrail by a company called Lamplas who manufacture the roof components. The guy, who goes around the country doing these repairs, visited our house and effected the repair. He did a fantastic job and you wouldn't know it had been done.

 

Alan

 

PS Having seen your photo now this is not the same as we had - ours were quite small. If yours were an aluminium roof I would have put it down to the aluminium expanding and stretching in the heat, maybe the fibreglass has expanded as after all the roof covering is usually 'loose laid' over the sandwich roof construction.

[Greenman14]

The roof is in 2 sections: a front section over the cab, up to the back of the over-cab roof light, and a rear section that covers the rest of the roof and ends a short way down the back wall of the van. It's the middle of this rear section that is affected.

 

Ps, my first thoughts were that the top skin had delaminates from the body of the roof (if it was ever bonded, or supposed to be bonded? in the first place) and the blisters were expansion, as you suggest.

[mgnbuk]

My T-Line 670 has a couple of similar "bulges" where the curved section of the roof meets the flat section & has had them from new. Not as pronounced as yours, & they have not changed noticably or caused problems in the 2 1/2 years since.

 

As far as I know the reason is that the GRP outer skin is floating over the roof structure and is only sealed & secured at the edges. With expansion, the bulges form.

 

[Wasnt Me]

Not sure if this will be of any help.......

 

I notice you have accessories fitted on the roof, were these done by the supplying dealer or another agent.

 

Surely if the roof was like this from new they would have noticed the blisters?

 

The dealer would not have supplied the vehicle knowing the roof was like this would they, or am I being naive?

 

Just an idea

 

Hope this helps

[George Collings]

As I understand it boats suffer from osmosis due to prolonged periods in water when the percentage of moisture in the composite of glass and plastic exceeds a certain level. It is not usually a problem when boats are hauled out for the winter as they dry out enough to stay below the critical level.

 

While motorcaravans get wet its for relatively short periods and they regularly dry off so its unlikely moisture content gets anywhere the critical level.

 

Its more likely bubbles that formed too late in the resin curing process and became trapped close to the surface but under the suns heat have expanded and gone pop. Ugly but easily patched.

[Greenman14]

Wasn't Me - 2015-08-24 11:00 AM

 

Not sure if this will be of any help.......

 

I notice you have accessories fitted on the roof, were these done by the supplying dealer or another agent.

 

Surely if the roof was like this from new they would have noticed the blisters?

 

The dealer would not have supplied the vehicle knowing the roof was like this would they, or am I being naive?

 

Just an idea

 

Hope this helps

 

The van was on the dealer's forecourt with the solar panel already fitted. The TV aerial was retro-fitted by the dealer prior to me collecting the van- for exactly this reason- warranty protection. Good point though, I'll ask whether this was noticed when they fitted the aerial.

 

[Brambles]

I think I have got my eyes around the pictire now, and you did say blisters and not ripples. I can see them now, really large blisters and this is not normal ripples you get from expansion of the sheet. I think its been bonded down on the curved area and air has been trapped or gases for some reason have build up. Maybe from treatmnet to the wood battens (or trapped moisture) or some other reaction taking place. The pressure has built up in pockets and the fibreglass panel has lifted in areas.

 

Simple test. Press down one side of a blister and see if the other side lifts. If it does it means you have air/gasses trapped under the panel.

 

Maybe it is my imagination but I can almost make out the zigzaging of how glue has been applied.

[Derek Uzzell]

Greenman14 - 2015-08-24 10:03 AM

 

Ps, my first thoughts were that the top skin had delaminates from the body of the roof (if it was ever bonded, or supposed to be bonded? in the first place) and the blisters were expansion...

 

I would also have thought that your Roller Team motorhome's GRP roof’s outer skin ought to have been bonded to the insulation beneath. Some motorhomes (eg. certain of the more expensive Rapido models) do have a roof construction with a ‘floating’ GRP outer skin but I’m doubtful that Roller Team would have done this.

 

Whatever the type of roof construction that’s been used, the blisters/bulges in your motorhome’s roof need addressing. It’s unfortunate that you did not inspect the roof last November (as then you’d know for sure that the bulges/blisters were not there originally) but no buyer could reasonably be expected to accept a brand-new motorhome with a roof in the state yours is in and - present originally or having developed during the last 10 months - the bulges/blisters are never right.

 

I strongly advise you not to present your supplying dealership with a DIY diagnosis. If - for example - you said “I think the roof’s outer skin has delaminated from the insulation, possibly because of heat expansion. I only noticed this after spending a month in Spain and France during July/August”, you’ll be inviting a response on the lines of this being what one might expect if the roof were exposed to very hot sun for a prolonged period. You’d be wiser merely telling the dealership that you have noticed the problem and are very unhappy about it. Just begin by letting them inspect the vehicle, draw their own conclusions and tell you what they believe can be done.

[kevina]

I used to make fibreglass (grp) products which were bonded with polyurethane foam. Sometimes a void in the foam would later show as this type of blister (palm sized or hand sized) after exposure to hot sun, more especially on coloured grp rather than white which stays cooler.

 

I'm not sure what the construction of your roof is but if t is grp there is a reasonable chance that the laminate (skin) is bonded to a foam core and what I describe has happened. It could happen with both the grp being bonded to the foam and the foam being bonded to the grp.

 

I'd like to see more photos and get a confirmation of the roof construction before saying more but if it is this type of delamination there is no way of fixing it.

 

Kev

[Greenman14]

kevina - 2015-08-24 3:06 PM

 

I used to make fibreglass (grp) products which were bonded with polyurethane foam. Sometimes a void in the foam would later show as this type of blister (palm sized or hand sized) after exposure to hot sun, more especially on coloured grp rather than white which stays cooler.

 

I'm not sure what the construction of your roof is but if t is grp there is a reasonable chance that the laminate (skin) is bonded to a foam core and what I describe has happened. It could happen with both the grp being bonded to the foam and the foam being bonded to the grp.

 

I'd like to see more photos and get a confirmation of the roof construction before saying more but if it is this type of delamination there is no way of fixing it.

 

Kev

 

This is my worst case fear, that what it might need is a new roof section assuming that this is possible as a repair. What I hoped to get from the collective wisdom of the forum is a feeling for whether this is a normal thing and not a problem other than cosmetic, or whether it's a significant issue arising from the original build,many right now, sadly for me, it looks like the latter.

 

[AlanS]

If you go on the AutoTrail website and look at the Autotrail TV there is a YouTube video of the factory construction of a Tribute motorhome which is almost identical to the Roller Team (same parent company). You will see the same part of the roof as you have on yours being installed and it looks as if it is a bonded roof with no floating roof at that point.

Alan

[Derek Uzzell]

Greenman14 - 2015-08-24 6:12 PM

 

...This is my worst case fear, that what it might need is a new roof section assuming that this is possible as a repair. What I hoped to get from the collective wisdom of the forum is a feeling for whether this is a normal thing and not a problem other than cosmetic, or whether it's a significant issue arising from the original build,many right now, sadly for me, it looks like the latter.

 

Athough delamination of body panels is not that common, it certainly does happen.This 2013 discussion relates to bulges/blisters on habitation/locker doors

 

https://www.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Delaminated-Panel/31464/

 

and I remember a dealer telling me (some years back) of an Auto-Sleepers coachbuilt motorhome needing to be returned to the factory as the GRP skin on one of the side body-panels had detached from the insulation beneath.

 

This 2012 video-clip relates to the construction of GRP sandwich-construction body panels in the French Fleurette factory

 

 

Fleurette makes bodywork panels itself rather than buying them in and it will be seen that the procedure is labour intensive.

[Malo37]

As a sailor of many years experience I can tell you that osmosis found in GRP yacht hulls is due to - well -'osmosis'. This is where small pockets of uncured resin (due to poor lay up techniques) remain in the structure. The gel coat acts as a semi permeable membrane so water passes through and pressurises the resin pocket causing a blister, usually no bigger that a thumb nail at most. For osmosis to occur the GRP has to be permanently immersed in water.

Not the case here which in my view looks like a much more serious case of structural delamination where the gel coat and/or a layer of matting has lifted away from the underlying structure do to poor bonding. This will not fix itself and can only get worse.

Personally I would consider this to be a major structural fault and demand my money back.

[kevina]

Interesting watching that Fleurete video Derek. They bond the cured grp outer skin to the foam/wood core with what looks like an (non contact) adhesive and then vacuum bag to pull it down tight. If someone could translate the piece at 1minute 58 that might confirm the adhesive used.

 

It's quite possible that Rollerteam have a different method of construction on the part concerned.

 

Kev

[Guest mikethe bike]

It is not osmosis. You only get that when the Gel Coat is submerged and being semi porous it absorbs a minute amount of water. If this water meets un-reacted resin it forms an acidic fluid that forms small blisters on the surface. When the blisters are burst they have an acrid smell.

Doh.....missed Malos post above.

[Brian Kirby]

kevina - 2015-08-25 11:12 AM

 

Interesting watching that Fleurete video Derek. They bond the cured grp outer skin to the foam/wood core with what looks like an (non contact) adhesive and then vacuum bag to pull it down tight. If someone could translate the piece at 1minute 58 that might confirm the adhesive used.

 

It's quite possible that Rollerteam have a different method of construction on the part concerned.

 

Kev

Doesn't shed any light, I'm afraid. All it says is that the surface of the polyester is rubbed down (poncé) before glue (colle) is applied. No specifics.

 

Back to the photo of the roof: definitely not normal, definitely take back to the dealer, and I agree don't attempt any diagnosis yourself. It is perfectly reasonable not to inspect the roof of a new van, few of us do. It might be reasonable to say how/why you came to notice it - presumably when you were cleaning the van. ;-)

 

I doubt that a spell in Spain would have any bearing on the appearance of the blisters: Roller Team are made in Italy (Cusona) where it also gets quite hot. Our daughter recently fled Rome for the Costa Brava because Rome was too hot! An Italian made van should be quite at home with temperatures we don't experience in UK - though it may not be quite so good with rain! :-)

 

There may be a perfectly simple fix, or a simple explanation. I hope so.

 

If not, and from what has been said above, I don't think it will be easy to fix, so you may have to push quite a bit. The main question will be whether it is detrimental to the integrity of the roof. It may genuinely be cosmetic rather than damaging, and I'd somewhat anticipate assurances along those being given. If they are (and IMO they'd need to be in writing, from Roller Team, and not just from the dealer), and you can live with that, the most practical approach may be to accept it as it is.

 

If you can't accept the van as it is, and want permanent rectification, I rather suspect (but I'm guessing) that the van would have to go back to Cusona for a new roof to be fitted. However, I have no idea whether Roller Team are geared up for that sort of remedial work. In view of all the adhesive bonded joints to walls and the rest of the roof it would not be easy. From your point of view, a replacement van would be the most straightforward solution, but that rather begs the question as to whether the defect is sufficiently serious to warrant its legal rejection.

 

But, until you get the van to the dealer, and he has consulted Roller Team on what is to be done, the above is speculation based on guesswork. Not intended to worry you with disaster scenarios, but intended as food for thought as to what you may need to consider if the dealer's answer is not satisfactory to you. Let's hope it is the simple remedy that is forthcoming.

[Greenman14]

Brian,

 

Thanks very much for this considered view. I agree and with my limited knowledge don't think I should be diagnosing the problem. I also think it's likely I'll be offered assurances that it's only cosmetic and if backed up by Roller Team that might be ok. I am thinking that a major repair carries its own risks and if the problem is genuinely cosmetic it would be best to leave well alone.

 

Thanks for all the advice.

 

David.