damp repairs to kontiki

[griff71]

hi guys n gals. been having a proper rummage through our new acquisition, i knew the old girl had a few issues of damp but i now found a couple others, the issues are around the hatches at the rear, not much rot on the wall board and about 6 to 8 inches from the edge. the main timber ledger is totally rotten so i'm gonna have a go at fixing it myself.
my main question for you all is this:-
if i use marine ply, could i also resin some marine ply together to make the main timber sections that the outside skirt screws to? i've seen similar done on boats so was thinking of doing this myself as i don't want my repair to rot in the future.
i have 4 areas i need to deal with, (that i can see) the main one being the hab door step, again the main ledger has rotted and also about 8-10 inches up the door frame.
i read a post on here the other day where a similar repair was done so i have a good bit of info to be going on with, just wanted to check the marine ply question.
thank you for reading.

p.s.
i'll post more pics as i start the job, just gonna order in some materials and get everything ready for the task.

 

[68c]

Not sure what age your Kontiki is. My old 1998 Swift Sundance, was a similar model. The floor had two layers of ply with a blue polystyrene foam inner. The sidewalls had an outer alloy skin, a white polystyrene foam inner with a wooden frame and thin ply wallboard inner.
Assuming yours is a similar construction I suggest cutting back the rotten sections and then rebuild rather than just overlay with marine ply. May seem like a lot of work but will give you a good van.

 

[rb62]

Plenty of information in this thread,it does move on to the lockers

My DIY damp repair project

Hi, This thread is intended to be a documented progress report on tackling some damp repairs in my motorhome. I hope it helps others and would like to invite anyone to chip in with help, suggestions, technical info and support.....because I am completely new to this. Firstly, some background...

www.motorhomefun.co.uk

 

[griff71]

68c i do plan on fully rebuilding where needed, what i was referring to with marine ply was glueing 2 or 3 pieces of 23mm marine ply together to make the wooden framework rather than using plain wooden joists, the ply would be cut to same dimensions as a piece of timber and used as the framework as well as used to replace the actual rotten bits of floor.

 

[68c]

Good to hear that, sorry I mistook your intention with the marine ply.

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[griff71]

68c, yeah i probably could have done a better job at explaining, i'm not looking forward to doing the whole job to be honest so i just want to try and use the most water resistant materials as possible so i never get the damp issue there again. the old girl needs reasealing top to bottom but all the damp is around the floor/wall joins, the outside bottom trim/skirt is cracked in several places so i will need to fix all that up too.
i've just spent the last year building a hot tub surround and gazebo with patios so was looking forward to chilling out for a bit, but now it looks like a new project is about to begin.
just got a few little jobs to finish out the back yard first so thought i'd spend the next couple of weeks trawling here for any info i will soon need.

 

[griff71]

rb62, thanks for the link, some of his issues are similar so more handy info. cheers

 

[Jamesh]

I'd not use ply as battens rather tanalised timber.

Cheers James

 

[Swifter]

Good luck . I’ve experienced this myself and although it’s irritating to have to deal with .when it’s sorted you will know the job is done properly.

 

[griff71]

cheers james, i was originally thinking that but just thought maybe laminating a3 or four strips of marine ply would work better but i'm probably trying to re-invent the wheel aren't i!
i'll probably source some hardwood rather than pine instead of my marine ply brainwave.
cheers again

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[griff71]

swifter, thats exactly right mate, i'm a brickie by trade but can put my hand to most things though i tend to avoid plumbing and electrics, i'm sure i'll manage to do the job to a pretty high standard if i've got the right materials and info.
i've got plenty of powertools, ie, multi tool, sander, grinder, mitresaw, drill, impact driver. got a few various hand tools too, so thats half the battle.

 

[Swifter]

Here’s my repair . You will do a fantastic job given your experience

https://www.motorhomefun.co.uk/forum/threads/☹%EF%B8%8F-rotting-floor-.237323/

 

[Eggs]

griff just be careful, doing damp repairs drives people to wearing outlandish shirts, doesn't it Swifter.

 

[griff71]

cheers swifter, i like your optimism.
the weather is gonna be my biggest foe but i've bought a cover so at least i can close the old girl up every night even if she's in bits.

 

[Eggs]

cheers swifter, i like your optimism.
the weather is gonna be my biggest foe but i've bought a cover so at least i can close the old girl up every night even if she's in bits.

Swifter nailed his damp in a matter of days, he did a great job of it.

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[griff71]

i'll have to go shirt shopping then eggs

 

[griff71]

here's a couple pics of the cracked trim, i don't think the cracks are the cause of the damp as some of them are below floor level, the seals on the tops of the trim are pretty much non existent and also the hatches need new rubbers as the old ones are pretty tired, so that is the probable cause. basically i'm gonna fix the damp, then reseal from top to bottom, i'm gonna take off every opening 1 by 1 and reinstall, ( maybe get some new vents as the old ones are yellow and ugly. then after all that crap is done and the inside has been reupholstered, etc, i may get to have a chillax somewhere with not a powertool in sight.

 

[Itsmcb]

That's identical to mine a 96 kontiki. When you remove the fiberglass skirt you will find that angled bit of plastic trip at the top of is just stapled on. The outer aluminium skin runs down below that and is screwed to the bottom timber frame. The rain just runs down behind that plastic trim and straight onto the batten.
I found that 25mm (treated) roofing batten is exactly the right size for replacing any rotted wall timbers. Sorry I didn't take any outside photos.
I've used external PU (gorilla) glue to fix all the timber and CT1 for all the sealing.

 

[TheBig1]

Laminated marine ply does work, but easy to get wrong and lose the structural integrity. Be careful how you source the timber. Tanalised is fine, so long as it has fully dried and seasoned. Otherwise the green can send stains through the ply wallboard. Use moisture activated PU glue, as it foams and seals any extra gaps in joints

Shame you are not local, as I have some very well seasoned hardwood, sat in my van waiting to be put away into my storage for future projects

 

[Badknee]

Earlier in the year we did Brassed Off Kontiki. The problems can fairly and squarely blamed on Swift’s terrible build systems and the quality of the materials used.
the floor as you have found is a ply sandwich with blue dense polystyrene but the ply is internal beech not external! The walls are just sat on the floor section and a very thin butyl tape silver backed stuck over it.
Keith cut all the floor rot out which was right across the back in the bathroom and put solid timber in there (ex woodwork teacher) and we glued and sealed all the joints. Then we used 50x50mm plastic angle glued in place of the rubbish butyl tape Swift used.
To do this we had to remove the whole of the fancy trim on the back but very carefull. It did go back well and was again all sealed up.

If you need any info give me a shout. Good luck

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[Itsmcb]

Use moisture activated PU glue, as it foams and seals any extra gaps in joints

Yes, excellent stuff

 

[griff71]

thanks for the tips guys, i've not had much chance to do any work yet as the weather has been shocking, i did yesterday take off the rear hatch and cut some exploratory bits out of the floor. the hatch had hardly any seal behind it and pretty much fell off one i'd loosened the screws, tomorrow i'm going to remove the gas box hatch and habitation door which will then allow me to remove the lower skirt.
i've got a good stock of tannelised timber, west systems epoxy, marine ply, sikaflex 522, do you guys recommend any other sealers or maybe even butyl tape to reattach door frames. any info will be muchly appreciated.
i'll upload some pics of the extent of damage once i'stripped it all back.

 

[TheBig1]

thanks for the tips guys, i've not had much chance to do any work yet as the weather has been shocking, i did yesterday take off the rear hatch and cut some exploratory bits out of the floor. the hatch had hardly any seal behind it and pretty much fell off one i'd loosened the screws, tomorrow i'm going to remove the gas box hatch and habitation door which will then allow me to remove the lower skirt.
i've got a good stock of tannelised timber, west systems epoxy, marine ply, sikaflex 522, do you guys recommend any other sealers or maybe even butyl tape to reattach door frames. any info will be muchly appreciated.
i'll upload some pics of the extent of damage once i'stripped it all back.

Be VERY aware that removing the door frame and refitting can cause major issues as they deform, then twist if not put back exactly as they were. The mastic tape is ideal for refitting as it gives a consistent bedding thickness

 

[griff71]

Be VERY aware that removing the door frame and refitting can cause major issues as they deform, then twist if not put back exactly as they were. The mastic tape is ideal for refitting as it gives a consistent bedding thickness

thing is the door frame has to come out as the lower timbers are rotten, the step is also rotten.
any tips for ensuring it doesn't buckle?

 

[TheBig1]

thing is the door frame has to come out as the lower timbers are rotten, the step is also rotten.
any tips for ensuring it doesn't buckle?

Open the door,
Remove screws
Close door and
Very carefully ease the door and frame out bit by bit
Don't lever or pull hard on any one point

Re-fit with door closed
With an assistant taking the weight of the door, put screws in without over tightening
Then tighten down evenly without distorting the frame

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[ashley 1340]

Hi I have had similar problems with my '91 kontiki which included a side wall and window opening . I stripped out all of the rot from the inside, not disturbing the outer finished panels, and then machined treated wood so that it was 1 mm smaller than the original . This was then covered in fibre glass resin and very fine fibre glass tissue which brought it back to the original size. After that I replaced the inner 4mm ply and decorated it. On the basis that if it works on a boat in the water its got to keep it dry on a camper van. It was a horrible job and there were times when I doubted the wisdom of such a drastic repair, but several very enjoyable years on it was worth the grief.......good luck

 

[griff71]

thanks for the advice, RE, the door, I'm gonna try get the main door off today. i don't think there will be much levering to do as the mastic seal looks pretty much non existant.
i took one of the locker doors off and that almost fell out. i'll need to braze one corner of the locker door frame as it has cracked on the joint due to the rotted timber not supporting it properly, luckily i have the tools for that as i had to braze aluminium profiles for a different project last year.
once i get doors and skirts off i'll post some pics as i'll be able to fully expose the damage properly,

 

[griff71]

well i got the doors off, also removed the metal step well which will need welding as its cracked, the sealant behind doors and skirts was pretty much doing nothing. the skirt needs some major repairs and the doorframe will need some straightening as it is not looking too great but i reckon if i use thin packers strategically placed when refitting i will be able to put it back better than it was.
gonna first start by repairing all rot damaged timber and ply, then fix skirt before moving on to doors. thankfully the days are getting lighter and fingers crossed the weather is gonna get better.

 

[jockaneezer]

griff71 when you mentioned "aluminium brazing" did you mean something like the Lumiweld rods you use with a gas torch ?

 

[griff71]

yes mate, i did some a while ago on some aluminium box sections so i have all the kit here, theres a broken weld on one hatch frame corner so i'll braze it together. aluminium is a bitch to work with as it takes ages to get to temperature because it sucks up the heat and dissipates it. But a bit of patience and plenty of gas to get it up to temp and she's a good'n

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