Cargo trailer issues?

[RVServiceGuy]

I recently started servicing RVs and figured out on day one how horrendous they are. I joined this forum because my wife and I want to build our own cargo conversion since RVs are overpriced junk heaps with a ton of features we don't need. I was wondering if there are any common problems or Achilles heels to them. If our build is successful I may have a few friends who want me to build theirs. I would like to get a general idea of things to prep and look out for so I can make this trailer something that will hold up more than the fifteen minutes RVs do.

[tnriverluver]

A good quality cargo trailer should last you a lifetime if properly cared for. I have a 1995 5 x 10 I use daily for work and most of those years it even sat out in the weather. Still about like new after a good buffing. My 2007 7 x 14 conversion has never had a single issue of any kind and I have towed it approx 20,000 miles now. It stays under a metal carport as well as the other trailer now when not in use. I look at buying a (real) camper or motorhome at times and just have to shake my head and walk away when I start thinking about all the leak issues most have in just a short matter of time.

[Rainier70]

Issues:
Check the trailer wiring for places it may rub or where they used poor connectors.

Install roof vents and windows if possible for good ventilation.

I think that no matter where you live, you need to insulate the walls, ceiling, and for coldest areas... the floor too, with foam board insulation. After insulating try and tape and seal the inner layer as a vapor barrier.

Watch out for the interior panels being put in with pneumatic nails (some may look like screws, but aren't). Request screws when you order.

When you are doing finishes keep the plywood on the walls under whatever you put on top. It supplies diagonal support bracing.

For less battery use replace incandescent bulbs with LEDs.

[RVServiceGuy]

Good to know. I've been doing service work in various fields for years. I got into RVs a month ago. It's great fun but I wouldn't own one. Most come brand new with leaks or other major issues.

[RVServiceGuy]

I know rounded roofs are tougher to do cabinets and finish work as they are more labor intensive. Any opions on the flat roof ct? I haven't gotten on one yet. Are they usually just straight aluminum with seals at edges or are they done like RVs where they have to be resurfaced every few years?

[Rainier70]

Spend LOTS of time reading the posts on this site. You won't believe the insight and help you will get before you buy.

Look at the Professor's cabinets on his build and how he compensated for the curved roof. I have a curved roof also. It does present challenges, but there are lots of ways to overcome them. Looking at how others did their conversion will give you ideas and inspiration for what you want to do. Everybody does it different. viewtopic.php?f=42&t=61680&start=75

I think most of the ct roofs are factory sealed or one piece. I don't think they have all the same issues as the RVs. I could be wrong there though.

Are you converting one to be a dedicated camper, or a toy hauler, or a camper/cargo hauler? How moveable or removable will parts of your interior be? Do you have a maximum towing weight to stay under?

6 wide or 7 wide?

The 7 ft wide cargo trailers allow you to put your bed in across the ct. Good for space, but harder for one person to crawl over. It also has more room, and usually is set up to haul heavier loads with brakes and tandem axles.

A 6 ft wide is lighter, less expensive, better for small mountain roads and seeing behind in your mirrors without extensions.

Then there is the extra height vs mileage question...... etc etc etc

Deciding some of those things will dictate many of your build decisions.

[lrrowe]

Same as Cindy said.

[RVServiceGuy]

I've been scanning over the builds. I've got a smaller build in mind for starters. Camper only, along the lines of a teardrop. I was looking at a tea drop build but it's just a little too small. Less than 4000lbs and I'd like to do a 6ft wide unit. Height needs to fit in my garage. If this build goes well enough I have several friends that may have me build them units as well.
My biggest concern are roof seams, front cap leaks. Those are among the biggest killers in rvs. I want this build to be a tank so I can do some long haul trips with my wife eventually.

[Rainier70]

Sounds good.

Roof are usually seamless or one piece in the cts. Front caps could fail though. I vaguely remember a post about a used ct that had a leak on the front seams that caused problems. I think some of the floor board had to be replaced.

The main difference is that the steel structure and foam insulation of the cargo trailers, doesn't all rot out even if you do get a leak. Most everything on a ct is repairable or replaceable. If it leaks a long time, you may lose some floor board or maybe even some interior wall board. I have seen pictures of a door that developed a leak and rotted out its wood framing. But all were fixable and the main structure was still intact.

On the other hand a leak in a RV with wood framing and fiberglass insulation is a disaster that all too frequently totals the camper.

[MtnDon]

Roofs: There is no standard roof. Some may be seamless one piece aluminum or galvalume, whatever. Others have machine crimped seams between panels. Check with the manufacturer, not the dealer.

Flat roofs, from what I have seen are not truly flat, there is some curve towards the center. The corners tend to be square in a so-called flat roof CT.

IMO, the biggest potential issue is in potential condensation of water vapor within the walls / ceiling. The aluminum skin is often going to be colder than the interior. That makes it a surface that water vapor will condense on. IMO, the ideal solution is the CarMate solution. CarMate trailers will build you a trailer with the plywood walls on the exterior. The plywood is a structural component. Most CT's have the plywood affixed on the inside. In order to insulate you need to remove the plywood , insulate and re-install the plywood. That gives you 1 inch of insulation . If you want more you have to decide how to proceed.

[Rainier70]

Not arguing with MtDon, but here is my reservation about the plywood on the outside under the skin. I don't own a CarMate, and I am not knocking them My thoughts on this are just theory and conjecture, and I am quite possibly all wrong. But IF there is condensation anywhere, it will most likely be on the inside of the metal skin. Having plywood next to the skin puts that wood in a very moist environment and subject to possible mold or rot issues.

On my cargo trailer the outside skin seams over lap from front to back. Those seams are not sealed. I could see thin slivers of daylight between the screws. I think that is a good thing as it allows an escape route for any moisture/water vapor that works its way in there. Maybe the CarMate is the same way, and maybe that is enough ventilation to make it a non-issue. Still I personally prefer a metal frame and all the wood components be on the inside where problems can be seen, corrected, and replaced if needed.

[lrrowe]

I guess time will tell on the plywood on the outside techique. I hope it will not be an issue.

To hedge my bets, my layering will be (from the outside in) exterior aluminum, 1/4 " plywood, 1 1/2" EPS foam, sealant tape over seams and interior plywood.

Now beofre I add the interior plywood, I will water seal the interior surface of the wall covering (probably with a marine polyurethane.

And when any chance of condensation being formed is present, I will crack the fan vent and maybe a window. I do not plan ???) on running a condensation making heat source at night either. Again time will tell. Oh and all my covering will be removeable should I ever want to check on things.

(Cindy, I do not know how the Nuway stove will factor into this equation should I that way)

[MtnDon]

I am extrapolating data from building homes, garages and barns. Metal walls and roofs over plywood or OSB have been used for decades with no issues with the underlying wood panels. A metal wall or roof with an airspace behind/under it does have condensation. And lots of it. The same metal over plywood, actually over plywood over something like building felt (tar paper) has no air space under/behind it. With no air space there is no condensation. At least that has been the track record with stationary structures. Time will tell if the extrapolation is/was accurate. My money (and trailer) has been bet on that.

[OverTheTopCargoTrailer]

Not arguing with MtDon, but here is my reservation about the plywood on the outside under the skin. I don't own a CarMate, and I am not knocking them My thoughts on this are just theory and conjecture, and I am quite possibly all wrong. But IF there is condensation anywhere, it will most likely be on the inside of the metal skin. Having plywood next to the skin puts that wood in a very moist environment and subject to possible mold or rot issues.

On my cargo trailer the outside skin seams over lap from front to back. Those seams are not sealed. I could see thin slivers of daylight between the screws. I think that is a good thing as it allows an escape route for any moisture/water vapor that works its way in there. Maybe the CarMate is the same way, and maybe that is enough ventilation to make it a non-issue. Still I personally prefer a metal frame and all the wood components be on the inside where problems can be seen, corrected, and replaced if needed.

Cindy

Let me put your mind at rest, there is no condensation problem with CarMate trailers.....other then they cost 2 x what GA trailers cost.

RVServiceGuy

....if you want the very best trailer for conversion start with a CarMate Trailer, wood walls & alum roof.
If you want it cheap get a GA trailer ..... I got both so I know.....

MY PET PEV HERE.... is that a lota folks got really strong opinions on something they (( they don't own , have never used, have never seen & they cant afford it )) but they sure can tell you what might be wrong with it.......
and I exclude MtnDon ....because he is very well read & educated and mostly 99% right on the money.....

Cheers OTTCT


http://overthetopcargotrailer.blogspot.com/

[RVServiceGuy]

My plan is to make it as modular as possible for quicker repairs. The RVs I have been dealing with are not conducive to easy repairs and long term maintenance. My goal is to produce something that will last for long periods of time with basic maintenance and care. I guess I'm thinking in terms of a 1950s product that was built to withstand a bomb blast. A lot of builds seem to go aluminum, insulation panels, interior plywood. I'm guessing they do well as we don't see many returns once the builds are done.