Sinking Roof

[vintageracer]

Here is what one person on the UHAUL site did to strengthen his trailer and mount "Stuff" on the roof of their CT-13 for off-road/Overlanding duty.

[George in BC]

I really like the idea of moving the loading from the roof to the frame!
Might try to use that on mine.
Thanks!

[Roamer]

I am about to pull the trigger.

I decided to put wood (two quality plywood pieces glued together, looks almost like a 2x4) braces on the inside on the ceiling. The green tape would represent where the support board will be glued to ceiling, and the tape is to contain the mess.

It will give me a place to put a hook to hang my wayward and homeless wok wile not driving.

I am hoping the epoxy will hold to the ceiling as it will be under tremendous load. Sanded and cleaned. I put one application of epoxy on the wood as I have heard wood soaks in the epoxy too much. The right side has 8 inches less ceiling since there is a cubby taking up space on ceiling.


To complicate things there is a center panel about 20 inches wide that runs the length of the ceiling that I do not want to trap, so the center portion will not have a glued ceiling piece. It would not have any structural integrity anyway since it is just screwed into place with a few shy screws. The center piece will have a small gap so the center ceiling panel can be slid out if needed. This makes 3 main beam pieces; two on the sides glued to the ceiling and the center one bolted firmly to those pieces. The center one can be removed and can be replaced if necessary for adjustments. I could have just cut a slot in the center panel so one long board could span across, but keeping the damage to a minimum is another goal, not that this is a collectible, but in the spirit of such, no harm done…
shown above is just the temporary osb guide pieces to represent the to-come-later support beams

When I drop the full weight of the ceiling on the new beam it will tend to pull the beam downward (or maybe just mostly towards the center), hoping the epoxy holds as mentioned, lots of stress. I imagine the jack could be pushing 300-500 lbs, but hopefully much less. I did crank it up over a couple of weeks and moved it at least two inches, maybe more-should of measured


I have pre set some guide boards to make sure the right and left boards are lined up. Later, before I remove jack, I will put finished boards where the osb is.


I have other plans for AC, so will not be putting an AC on the roof again,but that could change. All this work is now to just keep the sag out, keep water from puddling and help resale value if I sell it and want to put roof AC back.

One problems with this is that a roof AC will be blowing directly on the cross beam, but that is a small price to pay for structure. It will blow into the bed just fine and that is all that matters for me

[Roamer]

The deed is done.
Glued. I used plenty of hardener so it cured quick. The leftover almost burnt my hand…


The center board is OSB there just to keep the glued side-boards straight.


finger to block the light of window..

If I am happy with the strength of the bond, then I plan to pus an L-bracket of wood at the bed opening so I can put a board across to block the view of the mattress and bedding. It will need to be strong enough to crawl over. TMI, but the bed has HyperVent textile under the mattress so air can flow (prevent mold), the board will set away from the wall so air can flow to the HyperVent mesh. Then I can extend the mattress floor out to the board and keep the sheets from blocking the HyperVent. If that makes sense, then, wow….

[Roamer]

Here is the big moment:
The Lowering of the Roof. I tried to embed vid, but cannot.
https://youtu.be/misfbQvcP7k



[IMG]<iframe width="560" height="315" src="https://www.youtube.com/embed/misfbQvcP7k" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>[/IMG]

A creak or two and nothing broke, so far. It is a screw scissor jack, it squeeks. I have not put weight on the roof. It dropped only 3/4 of an inch.
To the far left the board was not bonded well, so I raised back a little then shoved more epoxy into the gap. I also forgot to put another board in the cubby hole on the right and screw into it. These might not make much difference except later one for overall strength…
So far so good.

Also good is that looking at the roof on top it now has an upward curve to shed water as it should, no more puddles. I was unsure how the roof would react front to back, I figured side to side, parallel to the brace would keep most of the shape.

Now just to hope this is strong enough for weight and rough roads. I have never really glued wood to fiberglass using epoxy under such a load, only for lesser fixes.

I did not worry to keep a gap for the panel to ever slide out. If so then I either jack it up again, like in vid, then remove panel, or just cut the panel. The bends at the end would have required a very big gap, so I just smacked it up close to the panel and bolted in.

rvpartscountry has a Coleman 9200 much cheaper than the undesirable amazon site, so I am considering a roof ac. my 13,500 is too much for 2200gen.

[Nor Cal Mike]

These trailers have a lot of flex in them. I can only imagine how much one would observe if you rode in the trailer while it is traveling down the road. I am not 100% convinced that epoxy alone will do the job. But we experimenters will never know until we try One possibility if you don't mind making a perforation through the roof would be to add a mechanical fastener. I used a stainless 5/16" stove bolt through my roof to fasten each of my bulkheads with some high quality caulking beneath to make a seal. It is easy to square the hole drilled through the fiberglass with a small triangular file to create a spin free application for the stove bolt. As for the caulked seal, I figured that the factory uses caulking on pop rivets so why not a stove bolt? and I am sealing a lot fewer holes than the factory did. If water leakage ever becomes an issue, I will just apply a small patch of glass cloth over the rounded stove bolt head. It would be hard to see from the ground.

[Roamer]

Lol, I had to look up "stove bolt". Answer, its a bolt, a bit superfluous to call it that? What did you mean?

Yes, after all, I am thinking that one bolt each side, near the center, will be a good safety. It will actually have to be through the non-glued center boards, but it will work just the same.
There are solar panels taped to the roof in the way otherwise.

I haven't worked with fiberglass epoxy enough to have certainties.
If my current fix fails the repair will be more than the first attempt.

I am thinking a wide n thick flat aluminum plate across the entire gap, which is maybe 15 inches. This instead of big washers. Two carriage bolts or hex bolts 4-5 inches will do, then cut off excess. All this will be under where the AC unit hovers (used to hover) anyway, so is concealed.


Well, the aluminum bar I found was flat but not real wide, I think it will do.

I had this stuff in my metal pile. Cut to width of the beam. The long metal aluminum will be the "washer" on the roof. It has holes, but too hard to try to hit those. I will run bolts up, then match the holes, drill and install. A little Lap sealant around the bolts should do it.

Thanks for the nudge….

This is not a trailer. It is a truck camper. All fiberglass, two shells, inside and out. The interior has built in bathroom and closet that make the interior supports closer to center and much more rigid. I think your trailers are shells with just wood things built inside that shell - less rigid.
My roof will still bounce I think since it sagged in the first place.

***update…. I found one Coleman 9200 AC unit refurbished $500 on ebay so bought it. 80 lbs or so. I should be able to sell my 13500 and break even.



The roof, two angles. The aluminum bar will be about here under the AC location.
It is really nice that all the vent openings are raised so no water can pool on the seal or the screws on a vent, yet it does not help any to support an AC on the roof

Did the cubby. Extra wood inside the cabinet and put a long deck screw through it all.

Pic Needs to rotate 90 deg clockwise…

[Roamer]

***I have no idea why it says "attachment" instead of showing the photo…

I got some motivation today…

Drilled from below using the black brackets as guide.
Attachment 130902
Daylight

Which left holes in the roof.
Attachment 130901
I then transferred the width of the holes to the aluminum strip.
Drilled that out…

Put the carriage bolts in and held with tape
Attachment 130903
I had to use vice grips to hold the carriage bolt from spinning, but it went easy otherwise.

I used caulk since the gun was loaded already. Tightened the bolts and smothered the threads a little
Attachment 130900
There was some creaking since the ceiling and roof were getting pulled together with only foam between, so I did not squeeze too much.

The inside is finished
Attachment 130899
I will wait for tomorrow to remove the support since I had to add a little epoxy to the beam earlier today.

The AC unit is on the way, 9200 model, hoping it runs fine on my 2200 generator or i may be cross.

[Roamer]

Removed the remaining supports and the total drop was about 3/4 of an inch.
Some creaking. I am not sure if it is the old roof creaking, or the new epoxy breaking. I can push up on the supports and it will move just a hair, but seems solid otherwise.
85 lb AC to be installed next week, so that and a drive will be the test…

[Thomcat316]

Park it someplace nice and hot in the meantime, a high temperature post cure will help the epoxy strength.

[Roamer]

heat? how long and how hot? I dont have places to park it, it is a truck camper so that would be monumental.
I do have a space heater….

[Thomcat316]

It's not absolutely critical, though if you're in a space that is cool it would be best to throw a space heater in it. 100 to 140 degrees Fahrenheit would be a good number, and over the course of a day would be a good time.

What sort of epoxy did you use for this?

[Roamer]

It is Bondo Fiberglass Resin. No additional details on the can.

[Thomcat316]

OK, that's not epoxy. It's polyester resin. Polyester doesn't have the same strength of bond and toughness as epoxy, and lends itself more to being used in lamination with fiberglass or other reinforcements than to being used as you have.

My suggestion of heat to enhance cure isn't likely to help much.

That said, your structure may work for a while, or forever, just fine. Don't try to fix it unless it breaks. If you do need to fix it, go to https://www.westsystem.com/instruction-manuals/ and https://www.epoxyworks.com/index.php...et-your-needs/ and read up on what can be done.

I've only worked with polyester resins to a very limited extent, as their problems don't outweigh their lower cost, for me.

[Roamer]

Thanks,
Well, that's not good. What I bought this Resin for originally was fine, but didn't realize it was not epoxy…

So, then the two bolts near center will not help so much, I instead need a bolt through the roof at the edges of this wood beam. The right side has been bolted through that cubby so probably will not break off, but the left could.

It may just take a minimal fastener. A screw and big washer….

[Thomcat316]

It may work great for a long time, also. That's a lot of surface area for adhesion. You may want to just see how it holds up, rather than adding another roof penetration.

[Roamer]

I hope it holds forever.
But, I put a small bolt through the roof, through the left beam on it's end. I used an aluminum 1 inch square tube about 10-12 inches long as the brace on the outside and gave it a little downward bow, it was from my metal pile again. There is no reason now that the resin would let go, the bolts are doing the work too.
My trips tend to be 6,000-7,000 miles at a time, so I couldn't risk it.

Well, the roof sagged 1/4 inch more overnight, but the resin held.
As I suspected when I jacked it up it not only bowed side to side as intended, but front to back also. The beam supports to the sides, but the 1/4 inch sag came from front to back,maybe. There is a downward bow to the top aluminum bar which was flat yesterday.
It will now puddle with water when rains, but not too bad. The beam seems to still be straight, it would take a lot to bend it, though maybe there is some play with the two bolts going through a wooden hole; today I cranked down on the bolts even more.

I was able to stand on the roof, then bounce a little and it is solid - no problem for 80lb AC unit then.

The settling will have a limit, and in the end should still give a lot of structural support to the roof. Somewhat disappointing…

Anyone attempting such a repair I would suggest a way to put tension across the beam to counter the forces. A cable with a turnbuckle would help, or a long threaded rod where tightening it would tend to bow things back up…

Since I built it in 3 sections and the middle is not glued, just bolted, I can at a later date, jack up the sides and put in a new center piece and drill new holes through it. I would have to jack it up an inch or more than I had with the current repair so when it sags is at the height I want.

For now I will see how it goes, no rush and this is all adjustable at any time.

It does not look bad, but is not the sleek fiberglass interior George Jetson is used to. The wood and combo with steel plate and bolts reminds me of really old wood ships, old technology, juxtaposed against the fiberglass shaped interior…

thanks for watching

__________________________________________

This is repost of my previous post which I cannt edit anymore. Pics in the message now. I tried to put the same pics in the same spot…

Drilled from below using the black brackets as guide.

Daylight

Which left holes in the roof.

I then transferred the width of the holes to the aluminum strip.
Drilled that out…

Put the carriage bolts in and held with tape

I had to use vice grips to hold the carriage bolt from spinning, but it went easy otherwise.

I used caulk since the gun was loaded already. Tightened the bolts and smothered the threads a little

There was some creaking since the ceiling and roof were getting pulled together with only foam between, so I did not squeeze too much.
In the end, I do not think this step was necessary, but given I used resin and not epoxy as I thought then this will help.
It seems this site only like for pics to be wider than they are tall, so apologize pic is sideways

The inside is finished

I will wait for tomorrow to remove the support since I had to add a little epoxy to the beam earlier today.

The AC unit is on the way, 9200 model, hoping it runs fine on my 2200 generator or i may be cross.

[Roamer]

I installed the AC, it felt quite heavy lifting it, but says 82 lbs on the ad, plus a few lbs for the ceiling assembly.
The measurement from floor to ceiling beam did not change. It dropped initially after I built the beam in there, but has stayed the same height even with time and AC unit.

I ended up moving the solar panels since the AC lapped over by about an inch. I didn't want them in any shade.

Hindsight:
Using threaded bolts was not wise. I either needed the threads only at the end, or need a metal sleeve to go inside the hole through the wood. I think what can happen is the threads will dig into the wood a little, at least down to the bottom of the thread groove. This is a little movement at the bolt, but leverages out to more movement elsewhere.
I am not sure this even happened; maybe the sheer friction of being tightly bolted together kept the wood from creeping any and letting the threads dig in. I won't know unless I take it apart and inspect it.

With this 3-piece beam I always have the option to jack up ceiling, and make a new center beam with new bolt holes in a position that will keep the ceiling higher than it currently is. The adjustment is limited only by how much and how far the roof/ceiling will move.