Fiat Ducato Posted March 25, 2015 Share Posted March 25, 2015 We have just bought a second hand Fiat Ducato Auto-Roller motorhome, 1997/98 reg. We paid a very good price for it, but we knew there was water damage on the ceiling, I checked the floors and walls are they appear to be ok, (not spongy) I have just started removing the roof light to inspect and see how bad it exactly is. And its pretty bad, it looks like its been leaking around the roof light for quite some time. I am looking for some advice on how best to tackle this, I have removed the lights. and the roof light. I thought I would take down all the ceiling as far as the cab as it appears dry there. cut a straight edge where I can join the new ceiling and old. I'm guessing all the insulation will have had it and need replacing. Then replacing the ceiling panels, I've been looking where you can buy these from for the proper motorhome ones. I am also thinking of upgrading the lighting to LED downlighters while I have the ceiling down. Which is the best insulation to use? and sealant to use? I have been researching the different ones Silkaflex 220 & 512 also Everbuild Stixall extreme power - this is their description of the product "Hybrid PMS polymer technology. Combined building adhesive and sealant, bonds and seals virtually everything to anything. Water resistant, can be applied to wet surfaces" Also Everbuild Puraflex 40 "Premium quality one-part high modulus polyurethane sealant and adhesive that provides exceptional resistance to mechanical wear. Used in the engineering, caravan and marine industries and for sealing floor joints in ceramic installations that are subject to high traffic. Excellent chemical resistance" These are half the price of Silkaflex 512, I've heard some people using Silka Silkaflex EBT from screwfix. The reason I am taking down the inside first before going up and sealing the outside is because I'm not sure of how they construct motorhome ceiling for structural support if its timber then they could all be rotted, if its aluminium or steel they could be corroded. I would appreciate any help and guidance on this matter. Many thanks Paul Link to comment Share on other sites More sharing options...
artheytrate Posted March 26, 2015 Share Posted March 26, 2015 Hi have a look at this thread on another forum the poster has exactly the same on a van conversion and he's doing very well repairing it. John. http://www.motorhomefun.co.uk/forum/threads/total-disaster.104663/ Link to comment Share on other sites More sharing options...
Guest Peter James Posted March 26, 2015 Share Posted March 26, 2015 Sorry to hear that. Bad news first, the previous link is interesting, but relates to a PVC where there are no structural problems to consider. The best post I have seen on this subject is from Dave Newell - the link doesn't work now so will copy and paste it here; QUOTE FROM DAVE NEWELL: Being an elderly Elddis its stick built, that is to say the frame is 1" square softwood with polystyrene infill for insulation, a thin plywood skin on interior with decorative coating and a thin aluminium skin outer with thin paint finish. Rebuilding a motorhome of this type with such extensive damp is a huge task; I know I was that soldier! I re-skinned a 1990 Autohomes Highwayman a few years back and had to reframe a quarter of the entire structure. There are three main areas that water gets in and whichever is the one (or more) in your case will need dealing with or you'll just end up with a damp motorhome again. The first point of water ingress is poorly fitted window seals. Second is roof to wall joints. Third is the worst, when water has got into the structure the wooden frame will eventually rot. Wet rot in soft woods as used for motorhome framing releases chemicals that will eat through aluminium skin in short order and will appear as tiny dots on the outer skin in line with the framework sections (often referred to as aluminium cancer). One and two are easily dealt with but three is a bugger as it means the rotten timber will need removing and the skin replacing. Replacing the frame timbers is difficult if the damage is extensive as once you start to remove the interior or exterior skin and rotten timber the strength of the body just evaporates. I did mine one stick at a time after removing the entire outer aluminium skin (not an easy job in itself) and replaced all rotten timberwork with 1" square aluminium box section screwed together with stainless self-tappers. For the roof I fabricated a TIG welded framework of 1" alloy box section, which was placed on top and screwed to the sidewall frames. Re-skinning was the most challenging part and took four of us three days to do the two sidewalls, rear wall and roof. Trust me when I say handling a 5 metre by 2 metre sheet of 0.8mm alloy without kinking it is not fun and spreading twenty odd tubes of sikaflex over the surface by hand is no easy job either! Sorry if this sounds negative but I write from personal experience of a similar project. Cost wise I spent over £3K at trade prices and took nine months to do it! Link to comment Share on other sites More sharing options...
Nobby Posted March 26, 2015 Share Posted March 26, 2015 Hi. Sorry to hear that you have damp problems. I have used Everbuild Stixall in a number of applications including some structural motorhome work. I have also previously used Sika and Soudal products and have found Stixall to be an excellent cost-effective alternative. Stixall comes in different colours and has good grab qualities that can be worked for an hour or so. Although it will stick wet items, I would advise removing any rotted wood and dry, treat and harden any edges before adding new wood. My only additional advice would be to not use sealant adhesives in an application where you may need to later remove it as it is VERY tough. For example, use a non-setting mastic for windows, rooflights etc as these can break or crack and need replacing later. Good luck. Modern adhesives such as those named make structural repairs much less problematic than they appear when you are tearing the rotten stuff out. Nobby Link to comment Share on other sites More sharing options...
Steve928 Posted March 26, 2015 Share Posted March 26, 2015 Regarding your 'ceiling panels' the technical term is wallboards and if you search Google using 'caravan wallboards' will you find quite a few suppliers such as O'Learys and Magnum. If you're not too bothered about getting an exact match then there are some bargains to be had. Ebay is also a source. A good yet cheap polyurethane sealant that I use frequently is Bond-It PU18, available on Ebay at just over £3 per tube: http://www.ebay.co.uk/itm/4-x-PU18-Polyurethane-Sealant-Adhesive-Koi-Fish-Pond-Car-Auto-Boat-Marine-GRP-/400728544517 Link to comment Share on other sites More sharing options...
Fiat Ducato Posted March 26, 2015 Author Share Posted March 26, 2015 Thank you for all your helpful comments, I'm not panicking or so shocked like the previous thread. I was aware of the problem when I bought it, and quite aware its a big job. But I'm a qualified carpenter and fully competent DIY'er so not phased by the scale of the job. I'm jJust not sure how the ceiling/roof of a coachbuilt motorhome is contructed. And until I satrt stripping it all out I won't know. Size of timber supports etc, Once again I appreciate all your comments, please keep them coming :-) Paul Link to comment Share on other sites More sharing options...
Guest Peter James Posted March 26, 2015 Share Posted March 26, 2015 Nobby - 2015-03-26 7:54 AM use a non-setting mastic for windows, rooflights etc as these can break or crack and need replacing later. Nobby My thoughts too. I used Plumbers Mait and it doesn't leak Link to comment Share on other sites More sharing options...
Tracker Posted March 26, 2015 Share Posted March 26, 2015 I did the same job on a Bedford CF Dormobile Deauville in the early 80s and the wet went on for much further than I realised which meant rebuilding most of the ceiling and wall panels and their framework. I took ages but time was more plentiful than money in them days but at least once all the wood and insulation, such as it was, was out finding the leaks was easy and it turned out the seams and windows were all OK as it was corrosion in the exterior aluminium roof panels. With all the holes resealed and a second aluminium skin fixed inside (recycled caravan panels stuck in place with marine grade sealant whose name escapes me now) I rebuilt the wooden frame and fitted polystyrene insulation tightly to help hold it all together then reskinned the inside with 1/8" marine ply which was painted both sides to seal it then wallpapered with a vinyl paper on the inside to finish before refitting all the furniture etc. Sorry I can't remember which sealants I used. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 26, 2015 Share Posted March 26, 2015 The first thing to do (as I’m aware Paul appreciates) will be to confirm how the motorhome’s roof has been constructed and what harm has been caused to its structure by the water ingress. If the roof’s structure has been extensively damaged (as shown in the example on this link) http://ivys.org/post/2010/07/06/Motor-home-progress.aspx it may be preferable (or necessary) to replace the complete roof rather than attempt to repair a badly rotted wooden framework. Link to comment Share on other sites More sharing options...
Steve928 Posted March 26, 2015 Share Posted March 26, 2015 Derek Uzzell - 2015-03-26 1:47 PM If the roof’s structure has been extensively damaged (as shown in the example on this link) Makes me shiver. German vans eh! Link to comment Share on other sites More sharing options...
Fiat Ducato Posted March 27, 2015 Author Share Posted March 27, 2015 What a state, here a few pics of what the ceiling looks like once I started taking it down. Link to comment Share on other sites More sharing options...
globebuster Posted March 27, 2015 Share Posted March 27, 2015 Who on earth would use Plumbers Mait !!!!!!! (lol) Link to comment Share on other sites More sharing options...
Brian Kirby Posted March 27, 2015 Share Posted March 27, 2015 globebuster - 2015-03-27 3:21 PM Who on earth would use Plumbers Mait !!!!!!! (lol) Retired plumber? :-D Link to comment Share on other sites More sharing options...
Tracker Posted March 27, 2015 Share Posted March 27, 2015 Brian Kirby - 2015-03-27 5:30 PM globebuster - 2015-03-27 3:21 PM Who on earth would use Plumbers Mait !!!!!!! (lol) Retired plumber? :-D Unretired plumber? I too have a tub of it in the garage as it is very good at what it does and I wouldn't be without it - but not for use on a motorhome! On the other hand if you have a holy bulkhead it is quite good for stoppering up bulkhead holes and leaky grommets - according to Wallace! Link to comment Share on other sites More sharing options...
Brian Kirby Posted March 27, 2015 Share Posted March 27, 2015 Tracker - 2015-03-27 6:06 PM................On the other hand if you have a holy bulkhead ........... Perhaps you could open your motorhome as a shrine, charge to visit the bulkhead, and sell indulgencies to the converts. Used to be a nice little earner, I hear! :-D Link to comment Share on other sites More sharing options...
Tracker Posted March 27, 2015 Share Posted March 27, 2015 Brian Kirby - 2015-03-27 6:55 PM Tracker - 2015-03-27 6:06 PM................On the other hand if you have a holy bulkhead ........... Perhaps you could open your motorhome as a shrine, charge to visit the bulkhead, and sell indulgencies to the converts. Used to be a nice little earner, I hear! :-D Nice idea Brian but as my bulkhead forms part of the unholy alliance between the oily bits and the clean bits the idea might better suit The Rev 'Holy' Dave Pelmet more than I! His bulkhead is much older than mine and more likely to need divine intervention to preserve it's holiness - besides which Dave needs the income to feed his penchant for collecting dogs - 4 legged and 4 wheeled! Link to comment Share on other sites More sharing options...
Guest Peter James Posted March 27, 2015 Share Posted March 27, 2015 globebuster - 2015-03-27 3:21 PM Who on earth would use Plumbers Mait !!!!!!! (lol) I used it for my roof fan 5 years ago, because it was all I had to hand, and it doesn't leak. B-) (Photo is a bit deceptive as van side door is open, so you are looking through it to the garden and it looks like flowers growing through the roof) Link to comment Share on other sites More sharing options...
Fiat Ducato Posted March 28, 2015 Author Share Posted March 28, 2015 Just an UPDATE on my progress, on starting removing the ceiling it was clear that all the structural timbers were soaking wet and rotted, I ended up removing everything right back to the Aluminium shell/sheet. The edge timbers were dry and could be saved. The existing ceiling that I took down was constructed probably pre-fabricated by Auto Roller in their own workshop and was made up of a sandwich of 1 sheet of hardboard, 25 mm polystyrene insulation and 40 mm x 25 mm timber supports with plastic cable ducts for the 12v cables then another sheet of white finished hardboard. And was not stuck in any way to the aluminium sheet, which I found weird. I located the holes responsible for the water ingress and temporarily sealed until inside is done, then the outside will be completely re-sealed around the roof edges, roof light boiler roof flu and bathroom vent. Thinking of using 25 mm Kingspan PIR celotex for insulation, 3 mm oil tempered hardboard for 1st layer and some 3 mm exterior plywood for the finishing layer. Was going to use the proper white caravan wall boards but due to the sizes will end up having 3 joins/seams - not keen on this.So thought I will use some white vinyl wallpaper with a nice pattern this way there will be no visible joins. Better on the eye. Will be replacing the 2 tatty existing ceiling lights with either 4 or 6 chrome flush LED down lights. Also the existing rooflight as been screwed down to the timber surround, now the timbers have gone I'm left with about 20 nail holes around the roof light. I am contemplating cutting the hole larger to cut out these holes installing a larger more modern roof light and just sealing it in with the correct product. Also all the softwood timber I put in I will treat with Cuprinol clear preservative and will be using galvanised screws. The are a couple of small surface rusty spots on the Aluminium where there as been water in the ceiling for so long, not corroded - thank God :-D Was wondering what I could use to treat and protect the Aluminium. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 28, 2015 Share Posted March 28, 2015 Fiat Ducato - 2015-03-28 10:36 AM ...Was wondering what I could use to treat and protect the Aluminium. How about Hammerite Special Metals Primer followed by Hammerite Smooth Finish (Silver)? Wouldn’t you be better to switch the 3mm hardboard and 3mm plywood around so that the hardboard is the ‘finishing layer? That way you ought to get a smoother surface for your wallpaper. It’s not going to be easy to manipulate large pieces of hardboard/plywood working from within the vehicle, so it might be preferable to accept that there will be several lateral joints in the ceiling and mask those joints with cover strips. Besides which motorhomes expand and contract significantly and, if you wallpaper the complete ceiling over the top of ‘filled’ joints, there’s every chance that the paper will split later on. I also suggest you use good quality stainless-steel fasteners rather than galvanised ones. Link to comment Share on other sites More sharing options...
Fiat Ducato Posted March 28, 2015 Author Share Posted March 28, 2015 Thanks Derek You've raised some good points, the only reason I was thinking of doing the sheets of board that way as when the motorhome was originally constructed it had hardboard towards/against the Aluminium, and looking at the decorative wall panels you can buy from several caravan and motorhome suppliers, they describe them as 3mm Plywood with a decorative faced front. They come in all different colours and designs however they are £23.00 each plus £19.20 p&p, And a lot if the companies say that the edges get scuffed during transit and there is nothing they can do about it. They need to be trimmed 10 mm all round. I've spotted some vinyl white wallpaper that looks almost identical to the pattern/design wallboard I was going to choose. Also the ceiling I took down the original one was in one piece with some paper covering the hardboard and that as remained in tact even with the sagging water logged ceiling ;-) I wonder if its even necessary to have a sheet of ply or hardboard against the Aluminium or whether you could just treat the Aluminium and then using an adhesive/sealant stick the celotex directly to the Aluminium skin. Seems strange how when they constructed the motorhome and fitted the interior ceiling they didn't glue it to the aluminium or fasten it in anyway. Link to comment Share on other sites More sharing options...
Guest pelmetman Posted March 28, 2015 Share Posted March 28, 2015 Tracker - 2015-03-27 7:10 PM Brian Kirby - 2015-03-27 6:55 PM Tracker - 2015-03-27 6:06 PM................On the other hand if you have a holy bulkhead ........... Perhaps you could open your motorhome as a shrine, charge to visit the bulkhead, and sell indulgencies to the converts. Used to be a nice little earner, I hear! :-D Nice idea Brian but as my bulkhead forms part of the unholy alliance between the oily bits and the clean bits the idea might better suit The Rev 'Holy' Dave Pelmet more than I! His bulkhead is much older than mine and more likely to need divine intervention to preserve it's holiness - besides which Dave needs the income to feed his penchant for collecting dogs - 4 legged and 4 wheeled! OI!.........I'll have you know there's nothing holy about Horace's bulkhead...........He's a devout atheist like his owner :D .............and similar to the OP I have no ceiling to my sponginess...........can you give us a tenner? :-S ...........my dogging costs have been astronomical this trip 8-).............. Link to comment Share on other sites More sharing options...
mgnbuk Posted March 28, 2015 Share Posted March 28, 2015 I don't think you should be attaching anything to the outer aluminium skin. As far as I know, the outer skin is "floating" so that it can expand or contract as required. The aluminium sheet will expand at a different rate to the composite wood / insulation panel beneath it. The board that sits directly underneath the skin will be to support it over it's entire area, as the thin aluminium will have very little strength in itself. As you are framing the roof yourself, it should be starightforward to replace the existing rooflights with larger replacements & frame accordingly. I had the standard opaque 400mm square central vent replaced with a Midi Heki on my last van, to good effect. This was fitted for me by Lowdhans, who changed the framing to suit. Lowdhams used Soudal polyurathane adhesive sealant (I asked at the time). I also had the opaque kitchen vent replaced witha clear Fiamma fanned vent, again to good effect - as you have easy access now, getting the 12v supply to the fan would be straightforward. I cannot emphasis enough how much difference these changes made to our Carioca - the living area was a much nicer place to be due to the large, light Heki & the extractor fan did double duty extracting from both the the kitchen and the adjacent bathroom if the bathroom door was wedged ajar. Aluminium can be primed with an etching primer - I got some intended for outboard motor bottom units from a boat chandlers for priming motorcycle alloy wheels. This was a 2 pack paint that went on yellow & changed to a greenish colour after the acidic content had reacted with (and keyed to) the aluminium. HTH & best of luck with the project ! Link to comment Share on other sites More sharing options...
Brian Kirby Posted March 28, 2015 Share Posted March 28, 2015 Unless the aluminium is showing signs of corrosion, it should not need painting. It oxidises with a fine powdery oxide that is thereafter generally protective. I assume you must have your van under cover to have got as far as you have. On that basis, I'd suggest you take a deep breath and remove the aluminium roof sheet as well. Then, you will be able to fabricate the new roof and ceiling as a panel, and install and fit it in onepiece as was done originally, working from the outside. That way, you could use full length facing panels, as you wouldn't have to try to work the boards etc through the van door. You have said you would finish by re-sealing the roof all round so, unless there are particularly complex joints to the rear wall and above the cab, I think removal/re-fitting the roof sheet would ultimately prove more straightforward. Be careful what you choose for the facing under the aluminium. If using 3mm ply, look for a thin fleece or similar as a separating layer to place over it before re-fitting the aly sheet. Make sure all ply is WBP grade, you don't want it to start de-laminating as soon as it sniffs moisture. If possible I'd avoid hardboard, as it tends to sag over time when it picks up atmospheric moisture. You should anticipate that some condensation will form on the underside of the aly sheet in cold weather and most timber will release an acid in the presence of moisture. I suspect that is what the "paper" you describe was for. I agree it would be better to leave the aluminium to float in preference to trying to bond it. It will expand more than the remaining structure and, if left floating, will absorb that expansion where it can. If bonded, it will tend to let go in places resulting in ripples that may cause otherwise avoidable problems. I very much agree with Derek that stainless steel screws etc will be better than galvanised. Best of all would be aluminium woodscrews, as there would then be no question of galvanic reaction between the different metals. Above all, do not use brass! Link to comment Share on other sites More sharing options...
Fiat Ducato Posted March 29, 2015 Author Share Posted March 29, 2015 Hi Brian Thank you for your input, and believe it or not, I've done all the work in my parking space just off the road, not under any cover. And that is why I really don't want to remove the outer aluminium skin if I can help it, creating more work for myself. So far I've left the cab area alone as its all dry the water damage seems to have only got as far as just above the dining seating area. I removed past this and the hardboard was incredibly hard to remove as it was so dry. The Aluminium skin is in very good condition overall, even on the outside. Apart from one hole the size of a 50p coin in the rear above one of the cupboards, looks like something as poked through, ally as been bent in. This looks like the main culprit for all the water, and not the roof light as I first thought. And about 5 tiny pin holes on the left hand side, probably caused by reaction from the chemicals released by the rotting wood. If I can treat these areas along with the rusty coloured patches which have appeared all over the ceiling, then I think this is the better option well at least for me, my circumstances, budget, lack of people to ask to help me (previous thread said it took him months, 3K of money and 4 men to help get the new Aluminium skin on) Done some research and I've found a product which is used on Commercial Aircraft's, Military vehicles and Marine called Zinc Chromate apparently is the best for applying to bare Aluminium for Anti Corrosion. A lot of the Etch primers are Acrylic - water based and come off quite easy if sanded or rubbed hardish. I have bought some Cuprinol Clear Wood preservative to treat all the timbers, existing and new with, I will be using Exterior Plywood with probably an extra coat of preservative for good measure on the outside facing side at least. The original roof that was fitted is a very small one 280 x 280 mm and not the sandwich type, but screwed all round from the outside down into the timber supports around it. These Timbers were completely rotted and all had to be removed. I am now left with about 20 or so screws left poking through. Potential water problem, So I am going to construct a larger timber opening probably 500 x 500 mm the cut out the holes/screws, and fit a Fiamma Vent 50 Roof light, sandwich type, more modern, opens 4 ways, fly mesh and roller blind and larger for more light. The existing one is tiny, winds up, fly net needs an hole in it for the handle, only opens one way and no permanent vent or roller blind. Think I will had one or two more timber structures in the ceiling too as from the roof light to the cab is a large gap of about a meter seems inadequate. I have ordered stainless steel screws and angle brackets. My plan is to pre fabricate the panels in 4 sections before carrying them in and fitting up into place, they will be 2032mm length by 1220mm wide, with the timber structures and celotex already fixed bonded to the oil tempered hardboard (to go against the Alloy skin) then late I will fit a finshing layer of either proper motorhome wallboards (white) with joining strips or exterior ply finished with some similar matching vinyl wallpaper, with joining strips to allow movement. Link to comment Share on other sites More sharing options...
Will86 Posted March 29, 2015 Share Posted March 29, 2015 Paul, Sound like you're well set up to conquer the problem. I'm not in favour of Alloy screws or any sort even if treated they can become scuffed in use. Always use stainless as you describe. I would also lightly grease the shanks before fixing. If the job were mine I would "consider" fixing a tarred industrial material to the underside of the roof. Even the old fashioned 'Underseal' to minimise moisture contact with the Alloy skin.The 50p hole could be sealed by a pair of stainless washers plus a stainless nut and bolt, and of course plenty of sealant. You could also add a pair of thin nylon washers to bed against the alloy skin. I cannot recommend any sealer's as I'm well past using any, but in my aircraft days (Gatwick) we used a yellow compound between all bolted or riveted fixings. Again where the pinholes are a similar method could be applied. You don't indicate where you are ... I make all manner of small stainless-brass-alloy and steel things and have presses and guillotines etc so if you have a problem shout, you can see where I live. Will Link to comment Share on other sites More sharing options...
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