Sagging ABS Roof Repair with Photos & How to tips

Discussion in 'Roof/Floor Repair & Maintenance' started by Miss Karla, Aug 9, 2018.

  1. Miss Karla

    Miss Karla New Member

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    Jul 10, 2017
    I have a 1997 Coleman Sun Valley with the dreaded ABS roof. Overall the roof was in fairly decent shape except for one major thing: serious sag. Unfortunately I don't have any photos of how bad it was, but we're talking at LEAST a 4.5 -5 inch sag in the middle of the roof, especially around (and likely in large part due to the weight of) the air conditioner. This substantial sag in roof led to another problem: a water leak around my AC unit as water pooled on the roof when the AC was used & spilled over the top of the gasket & into the inside of my newly remodeled camper!

    After a bit of research on the Pop Up Portal & YouTube, I knew what I had to do! Off to Menards to buy some Uni-strut, Uni-Strut plates & bolts & spray paint. Supplies came to $160.

    Below are pictures of the internal bracing system we installed. Luckily I have a friend who is handy with a welder. After I sent him some photos & videos of what I thought needed to be done, he was willing to take on the job.

    Basically the two end pieces were welded to fit the arch of the roof & screwed to the metal plates on the lift system at the ends of the camper near each bunkend first. This was the most time consuming part of the project because it was important to measure the angles & get the first piece just right. After that things went quicker. The beauty of this bracing system is that we never had to drill any new holes into the ABS roof.

    Normally the camper door fits into glides & snaps onto the ABS ceiling when not in use & the camper is folded down. These glides, snaps, and also the cord channel for the AC unit had to be removed so that the two lengthwise Uni-Strut braces could fit flush against the camper ceiling. On my Sun Valley model the cross piece of Uni-Strut on the couch end of the camper ran into a fold-down clothes hanger. We just cut a notch in the Uni-Strut to accomodate it. The clothes hanger is no longer useable, but it seemed like a small price to pay for a roof that doesn't leak.

    After the lengthwise braces were attached to the crosswise pieces with the Uni-Strut plates & bolts, a simple A-frame suport was made out of scrap 2x4's with a leftover piece of Uni-Strut attached to the top. This support was then placed underneath each lengthwise brace & the roof was then jacked up & tightened into place using an ordinary hydraulic car jack. My own opinion is that it's important to try to do this on as hot a day as possible so that your roof is its most malleable from the heat, giving you the best chance of jacking it up without cracking the ABS. On the day we actually jacked the roof up the temperature was in the low to mid 90's. (Welcome to summer in August in Iowa! Lol) One of the things I didn't like when I talked to commercial camping outfits was that the very few who were even willing to look at my roof problem would only consider it as a winter job. To me, trying to jack up an ABS roof in the winter in Iowa, even if it was in a heated garage, sounded like a great way to crack my roof & then have to sell me either a new roof or a whole new camper, (which all of them had already tried to do at least once when they heard what my problem was anyhow.) NO THANKS! This is part of what gave me greater incentive to try & fix it myself with the help of my welder buddy, & I'm so glad I did!

    All in all, the project took about 20 hours, which included shopping, measuring, drawing the angles on computer software, cutting & welding the Uni-Strut, spray-painting, sanding, removing the door & AC cord glides from the camper, final installation & jacking up the roof. Being a first -time try, if it had to be done all over again, I think it would probably only take about 12 hours.

    I am THRILLED with the results! There is ZERO sag around the AC unit now & at its worse spot, there is maybe only 3/4 - 1 inch of sag left max, where before it was easily 4-5 inches of sag. Best of all, the roof drains as it should & no more water leaks! Now I'm on to my next roof project: MEK & ABS pellet repair for a few minor hairline cracks around the edges of my NON-sagging ABS Coleman roof, & a beautiful coat of bright orange Grizzley Grip for a whole new sun-resistant, crack-free look. I'll let you know how it turns out!

    I hope this helps anyone who might be thinking of tackling their own sagging ABS roof. Trust me, for easily less than $200 it's TOTALLY worth it!
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    katdancin, FlyboyTR and megcabra like this.
  2. Sjm9911

    Sjm9911 Well-Known Member

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    May 31, 2018
    Nj
    Nice tutorial! And happy it's fixed.
     
    Miss Karla likes this.
  3. myride

    myride Well-Known Member

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    May 14, 2015
    Edmonton, AB
    Well planned and executed Miss Karla....well done.
     
  4. Miss Karla

    Miss Karla New Member

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    Jul 10, 2017
    Thank you! It turned out to be a pretty cheap fix. Hopefully it will help other folks with the same problem. As long as you can find someone to weld the end pieces for you, it's really pretty straightforward
     
  5. Miss Karla

    Miss Karla New Member

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    Jul 10, 2017
    Thank you! (And me too! )
     
  6. CoolCanuck

    CoolCanuck New Member

    Great it worked for you. I'm about to start the same repair project on my '97 Coleman SunRidge.
    I priced out the Unistrut here locally (10ft sections, Galvanized) at CAD18.00 a piece, plus the bolts, T-joiners and 90 degree angles for attaching the Unistrut to the camper. I will be using the solid style without the holes on the back. These are a bit stronger.

    I will be using a white paint (brushed) called Corrostop 631. I have used it in the past on some auto projects and it is very tough.

    I will be removing the clothes hanger, as it is also in my way, rather than cut the Unistrut. Cutting the Unistrut to fit around the hanger will weaken it quite dramatically in that area, as it has lost its' rear back. It is no longer an inverted "U" beam, rather, just two single vertical pieces of metal, so to speak. It is easy to seal the holes in the interior ABS using white Sikaflex or 3M 5200 sealant. Don't use Silicone. Inject the Sikaflex/3M5200 into the hole by pressing the nozzle right in. Then using a wet finger, flatten it out on top of the hole. This is a permanent, waterproof repair.
    I use these products quite a bit, anywhere where I want something 100% watertight and I don't envision having to remove the part. Only way to get it off is to cut it/saw it etc.

    I can then relocate the hanger or add another one.

    I'm still wondering though about bolting the Unistrut to the 'beauty covers' over the lift struts. Though I have not removed mine yet, it appears as if the covers are only screwed into the ABS with 4 sheet metal screws each. The top bent over flap of the cover is resting on the outside part of the lift strut. By bolting the Unistruts in this way, would the load path not be ending in those 4 itty-bitty sheetmetal screws attached to the ABS? If so, then he longterm effect here will be cracking of the ABS where these screws go in.

    I will investigate attaching a flat sheetmetal piece to the top of the two bent over lips of the lift struts, at the top, facing the inside of the camper. These would then be hidden by the beauty panel. This would transfer the load path directly to the lift struts and not the ABS shell, thereby preventing further problems down the road.

    There are some good pics of this area (and for the same repair using Unistrut) at https://www.hybridexplorer.com/forum/index.php?topic=129866.0 . See post #5 for the area I'm talking about.
     
    Last edited: Aug 18, 2018
  7. Miss Karla

    Miss Karla New Member

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    Jul 10, 2017
    Good ideas. Yeah, the guy that was helping me with this project didn't ask me about the clotheshanger, he just notched out the unistrut & it was already done. Like you said, it certainly weakened the unistrut, & if it was me, I probably would have just taken the clothes hanger out, but I wasn't going to mke him do it over at that point. The Unistrut without the holes would have been stronger too, but this will probably outlast my camper which is already over 20 years old, & the holes are handy to zip tie light stuff to! Good luck with your project. I just live having an AC that doesn't leak into my camper anymore!
     
    myride likes this.
  8. CoolCanuck

    CoolCanuck New Member

    Well, I started mine today...
    Removed the clothes hanger by drilling off the 4 rivet heads holding it in place. Removed the hanger and then pushed in the short rivet remnants, so that I can Sikaflex the hole after I'm done.

    Then on to removing the door tracks. Same procedure, drilled out the four rivets holding the ends. Mine were solidly, yes, really solidly glued to the inner ABS shell. I used an offset flat screwdriver (to get more leverage) under the tracks, protecting the ABS from all too much damage by using a wooden stir stick from HD under the screwdriver 'Head'. HAd to go over the remaining glue and plastic with a sharp chisel, perpendicular to the glue line. With some sharp blows of a hammer, the remaining glue/plastic came off reasonably well.

    Guess tomorrow I'll build the inner temporary shore walls and lower the roof onto them for a few days to hopefully 'condition' the ABS roof to take it's old shape back. Guess it'll be similar to me trying on jeans from my early 20's...
     
  9. tlee01

    tlee01 New Member

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    Aug 27, 2017
     
  10. tlee01

    tlee01 New Member

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    Aug 27, 2017
    CoolCanuck,

    Very interested in how you end up attaching the struts. I too wonder about the strength and longevity of attaching struts to the beauty covers of the lift struts. I see pictures of it being done on several posts but I am also concerned. Please post updates or pictures if you can. Thanks
     
  11. tlee01

    tlee01 New Member

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    Aug 27, 2017
    Miss Karla,

    I have a 98 Niagra with the same size roof. Any way you can post a close up photo of your plans so I can see the dimensions your friend used to modify the uni struts. Fantastic job. Thanks
     
  12. CoolCanuck

    CoolCanuck New Member

    I don't have any pics yet, but will post soon.

    I put some green painters masking tape sideways across the bend on the inside. The location is easy to determine with
    a. your fingers
    b. an 18" straight ruler. You'll readily see when it hits the bend.
    Place a mark on the tape on each side. The flat center portion OF MY roof measured 36" between the marks. Then measure out to the beauty covers.
    These measurements vary from camper to camper.
    The center 36" is flat on my trailer within the first foot or so towards the center, then dips slightly. It appears as if my 97 only has the crown in one direction.

    My welder only was able to get the Unistrut done this morning. Still have to file and fit it in, then paint.

    I found that that it may be counter-productive to hard-mount the Unistrut to the lifter struts.
    The beauty cover has a folded over flap near the top, to which are welded two screws. These screws fit into two slots on top of the struts. I'll try to get some pics tomorrow. It was already dark tonight and I'm working outside. As it is quite windy these days, I am only able to remove one beauty cover at a time, even though I have 2x6 and 2x4 bracing under the roof. Once the beauty cover is loosened and removed, there is nothing apart from the fabric holding the ABS roof onto the camper. Not a good idea with gusting wind.

    It appears to me that the struts are allowed to "float" in a fore-aft direction where they are bolted to the beauty cover. This may be to accommodate movement on uneven terrain. Unless of course the nuts on my camper were not tightened fully. Don't know yet.

    I also found that after finding the vertical centerline on the beaty covers, I have a bit more than 10 ft between the two Unistrut cross braces, which means that I have to move each one of these slightly inwards from the centerline (around 3/16" on each one, so far).
    ***EDIT 2-Jan-2019 : It turned out to be even less than that, just needed to file a bit of the outside facing edge of each hole. I actually ended up using my Dremel rotary tool with a Carbide insert. ***
     
    Last edited: Jan 3, 2019
  13. tlee01

    tlee01 New Member

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    Aug 27, 2017
    Really helpful insights that I've never seen before on many posts on the repair. Thanks for sharing. Please continue to share along with pictures as you proceed on the repair. Every bit of knowledge builds one's confidence to take this on.
     
  14. Miss Karla

    Miss Karla New Member

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    Jul 10, 2017
     
  15. Miss Karla

    Miss Karla New Member

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    Jul 10, 2017
    Thank you. I'm thrilled the sag is gone & the roof no longer leaks!
     
  16. katdancin

    katdancin New Member

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    Oct 19, 2016
    Great job!!
     

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