Caravan Damp Repair

  1. Barlidge

    Barlidge Member

    Messages:
    875
    Location:
    Langford, Bedfordshire, UK
    So have finally got round to looking at the damp corner of my caravan, know about it for a while and it was coming in from the awning rail which I temporarily sealed a while back and hoped it would dry out - nope!

    Have started stripping back some of the interior to let it start drying while I look at resealing the awning rail and some other external bits. Most of the timber is not too bad and am hoping it will dry but the corner plywood piece is too far gone I think and while I dont think is is integral to the strength of the box it does have the awning rail screwed into it which is under tension when fitted and it also serves to bond the GRP/side panel joint.

    So my current thought process is to make some surgical cuts as shown in the picture below with the yellow dashed lines - these should hopefully give me enough access to replace that piece while being able to hide most of the joins either behind the top of the wall unit or behind the corner shelf. The two areas that will be visible can be blended in with matching tape as the original panel joint in the red dashed lines.

    All thoughts and opinions welcome.


    Damp area
    IMG_3599.jpg

    Delaminated Plywood Corner Piece
    IMG_3600.JPEG

    Inside Rear GRP - Only the Ply seems to have suffered
    Inside Rear GRP 2.jpg

    Roof Composition - Outer plastic covering, 3mm ply bonded to polystyrene bonded to 3mm ply.
    Roof Sandwich.jpg

    Above PLY Diagonal Piece
    Top of Plywood.jpg

    Behind Awning Rail
    Behind Awning Rail.jpg

    Proposed Cuts
    Cuts.jpg
     
  2. sg66 Member

    Messages:
    544
    Location:
    northeast
    Just cut out what needs cut and replace, you can put a bigger bit of ply in top corner, make sure timbers are OK though as it would be a shame to go that far and end up with awning rail pulling away and leaking in future.
     
    Barlidge, stuvy and Parm like this.
  3. Melvyn Best Member

    Messages:
    431
    Location:
    Cambridge
    Have a look on the motorhome fun forum, there are a couple of similar repairs on there with loads of info and supplier details
     
    Barlidge and stuvy like this.
  4. Barlidge

    Barlidge Member

    Messages:
    875
    Location:
    Langford, Bedfordshire, UK
    That's what I was thinking, I have a big awning hanging off it as well.

    Will take a look, cheers.
     
  5. Barlidge

    Barlidge Member

    Messages:
    875
    Location:
    Langford, Bedfordshire, UK
    I have made more progress - finished stripping the sidewall as far as I need to go and left a little existing polystyrene to enable me to stagger the joint on reassembly to keep as much strength as possible.

    Have also stripped as much as needed on the back wall - I was going to go about 30mm larger both directions as you can see by the pencil lines in the picture so that both those cuts would be behind the cupboard vertical and horizontal pieces but I came across some nicely placed screw plates which will add strength on re assembly so I decided to sacrifice hiding the joins in favour of using those which saved me a job of adding them later which I was planning to do. The joins will still be inside the corner shelf area so hopefully not too visible.

    Same story with the ceiling, again as far as I need to go and with the overlap joint for strength, there is metal screw plates there also but I might add 2 more for good measure.

    So after a good few hours I was finally able to remove the ply corner piece which was totally shot, luckily it came out in one piece so I can use it as a template to make a new one. Next jobs will be tidying up all the edges and any polystyrene that's left and removing all the old sealant and getting it ready to start rebuilding. It would appear it was leaking both from the awning rail and also the joint between the back panel and roof skin.

    I bought a new toy - a DeWalt DCS355 18v multi cutter, I already have a drill and driver with 3 batt's so only needed the body - absolutely fantastic tool and was invaluable on this job, especially for cutting the hidden screws out - I will also use it for work afterwards.

    IMG_3647.JPG
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    IMG_3649.JPG
    IMG_3650.JPG IMG_3651.JPG IMG_3653.JPG
     
    sg66 likes this.
  6. sg66 Member

    Messages:
    544
    Location:
    northeast
    Looking good, have you got panels and bonding yet
     
  7. octo0072000

    octo0072000 Member

    Messages:
    5,345
    Location:
    south yorks
    you need to do the roof seam as well at the back by the look of it too ask me how i know :clapping::clapping:
     
  8. gaz1

    gaz1 Forum Supporter

    Messages:
    10,441
    Location:
    westyorkshire
    im going to stick my nose in here and ask some questions

    how old is your caravan?

    can you provide an external picture of it front side and back if possible cover number plate up

    that seal looks so poor and the roof seal well its not good thats definate

    I can see a way around this issue and to really sort the caravan out to fully seal it

    weight is the issue here i presume its aluminium outside by the look of it ?

    or is it plastic as theres other tech nowadays with plastic does a much better seal and can also be used as an extra insulation barrier
     
  9. sg66 Member

    Messages:
    544
    Location:
    northeast
    Modern vans use fully bonded construction with no screws, they still leak, not as bad as older ones but leak non the less.

    There is a lot of flexing, the awning side in particular gets a lot of strain when the awning is used.
     
    Barlidge likes this.
  10. Barlidge

    Barlidge Member

    Messages:
    875
    Location:
    Langford, Bedfordshire, UK
    Thanks Steve, no not ordered anything yet, probably get the panels from O'leary's or Halesowen, sort of fitting the caravan in around other jobs round the house. I often use a full size awning with annex on so wont me will need to make sure everything is bonded up well.


    Yeah as above that was part of the problem - will be stripping that joint completely back soon and re doing it.



    Its a 2005, aluminium skin forming a bonded sandwich with the insulation and 3mm inner ply skin, I will be removing and resealing resealing all the trims over the next couple of months, weight is always an issue.

    IMG_3657.jpeg
     
  11. Barlidge

    Barlidge Member

    Messages:
    875
    Location:
    Langford, Bedfordshire, UK
    Thought I better get on with sticking it back together, I am adding some supplemental battens not so much for strength but to give extra surface area for the inner skin to bond to as I can't really staple it at the edges like the original was. Sikaflex 512 applied to both surfaces.

    After sticking the corner piece in and as I was cleaning up the surface for the batten in the next section down I found a small pinhole :mad: I am thinking a small piece of aluminium patch sika'd on from the inside then clean the outside up and JB weld over it and paint.


    IMG_3988.JPEG IMG_4047.JPEG IMG_4049.JPEG IMG_4050.JPEG IMG_4051.jpg IMG_4052.jpg
     
    monky harris likes this.
  12. octo0072000

    octo0072000 Member

    Messages:
    5,345
    Location:
    south yorks
    that's the trouble with older vans they was built from the inside out tin went on last
     
    Barlidge likes this.
  13. tom2207 Member

    Messages:
    1,607
    Location:
    uk northern ireland
    Devcon A is very good .
     
    Barlidge likes this.
  14. Barlidge

    Barlidge Member

    Messages:
    875
    Location:
    Langford, Bedfordshire, UK
    Thanks, I would have maybe tried that but already had some JB in the shed.

    One step forward and two steps back :clapping:

    Making more progress, filled the pin hole, stuck the side marker cable in place, finished the extra battens, cleaned up all the panels ready for glue and started cutting the insulation.

    I wasn't happy with the bottom corner as some of the timbers looked a bit suspect so cut another access hole which also nicely gave me access to the back of a fiberglass repair I also need to do. The timbers for the walls were actually ok but while poking around in that corner I found a small area of rot in the floor, doesn't seem to extend very far but that will be something else that needs looking at.

    Pics ...

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    jsf55, tom2207 and sg66 like this.
  15. sg66 Member

    Messages:
    544
    Location:
    northeast


    Sides are bonded complete sections and installed as such, you have to go back to pre bonded construction when they were skinned
     
  16. EddyP

    EddyP Member

    Messages:
    493
    Location:
    Northants
    I did a damp repair to our caravan last year, it's put me off having another one seeing how badly built they are!

    I think I've got some vinyl wall paper the same pattern as your walls left over, was going to put it on Ebay....
     
    Ashley Burton likes this.
  17. TechnicAl

    TechnicAl Member

    Messages:
    7,477
    Location:
    Rotherham
    Its only 2 years older than mine....no damp at all...mind you we have had it about 10 years now....I get it serviced every year and for the past 5 its probably done less than 500 miles per year
     
  18. sg66 Member

    Messages:
    544
    Location:
    northeast
    It's got it its just not been found.
     
  19. TechnicAl

    TechnicAl Member

    Messages:
    7,477
    Location:
    Rotherham
    checked every year....no damp at all.......ive also got a meter but if its damp you can smell it.....dont use an awning which is a big cause
     
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