6x14 enclosed cargo trailer structural support.

Hello everyone and thank you for helping. I have been to many forums but have not seen an answer to my specific question.

 

I have bought a 6x14 enclosed cargo trailer and plan on making it a small living quarters.

I asked for no plywood on the walls, but they said they had to for transport, so this got me to thinking.

 

I want to keep the weight down. The trailer weighs 1300 pounds with 3.8 inch playwood on the walls and I was thinking of insulating the walls with foam board then covering with paneling or some light weight material to save weight.

 

So what is the best way to keep the structural safe and decrease the weight of the walls at the same time? 

Would foam insualation be strong enough?

Do I need to add cross members to the frame?

Can I use lighter plywood? Which I really do not want too because it is still heavy. I would like to keep the wallboards below 10 pounds each for a 4x8 sheet.

 

Any help would be appreciated, this is my first attempt and I do not want the trailer ripping apart while hitting 40 or 50 mile per hour crosswinds or headwinds.

 

Thank you.

  • Manufacturer:Cargo Mate
  • Model:BL614SA
  • Length:14'
  • Width:6'
  • Weight:1400 lbs
  • GVWR:2990 lbs
  • Axle Capacity:3500 lbs
  • Axles1
  • ConstructionSteel Frame Aluminum
  • Pull TypeBumper
  • RampsYes
  • Roof TypeRound
  • Nose TypeRound
  • ColorWhite

EAR RAMP DOOR W/SPRING ASSIST

DOOR HOLD-BACK
LEAF SPRING AXLES
SILVER POWDER COATED WHEELS
STEEL BELTED TIRES
LED LIGHTS
36" RV SIDE DOOR UPGRADE
BLACK CENTER CAPS
GALVANIZED ROOF
16" STONEGUARD
2 INTERIOR DOME LIGHTS
1 WALL SWITCH
ROOF VENT
3/8" PLYWOOD WALLS WITH LUAN TRIM
3/4" PLYWOOD FLOORING 
ATP EXTERIOR ALUMINUM FENDERS
TPO RADIUS FRONT CAP
DOT APPROVED LIGHTING
LICENSE PLATE HOLDER WITH BUILT IN LIGHT
.030 ALUMINUM EXTERIOR
Z-TECH UNDERCOATED FRAME
WELDED SAFETY CHAINS
STEEL SEALED SIDEWALLS

I am not sure of your goals or reason on keeping the trailer light.   Is it because you are going to be transporting stuff and you do not want to exceed the tire / axle capacity or are you trying to conserve energy or is your tow vehicle a little stretched on pulling the larger trailer?    - Assuming it is one of the first two.   

Things worth considering:

1/ Wind loading - due to motion down the road - a force will be applied to the front of the trailer pushing toward the trailer axle.

        - Side Loading - heavy crosss winds and about any time a semi passes you or you pass a semi

        - diagonal wind loading

      The trailer structure is a skeleton of steel vertical supports and roof cross members - the .030 aluminum skin adds near zero structural integrity. I am sure there is some but not a factor in trying to determine where you can lighten your load.    Most of the trailers i have seen come standard with sheating on the sides.   If you want it on the roof it is extra.

  I am not sure what type of wood your ply wood is - 3/8" general weight is 34lbs., 1/4" is 22-3/4lbs. per sheet.  Insulation is about 1 lb. per cubic foot.  or 4 lbs for a 4 x 8 x 1-1/2 sheet

 

I live in Grand Junction Colorado and usually base camp at about 9,500 feet.     - in early September it gets in the low 40's or colder.  I am leaving my side walls as they are and insulating the ceiling only to start with.   1-1/2" insulation with the reflective sheet on one side - I used two 3/4" sheets - I am reflecting both toward the ceiling and toward the living quarters.   Trying to keep it cool when I am in Moab.

 

My trailer is 8' id x 24' id x 7' tall - I only insulated 16' of it.   I use a piece of 8' x 7' carpet that I hang to make the living quarters 16' long - if it is just me, I reduce the living quarters to about 10' - less to heat.   I used luan for the ceiling - alot of people will use FRP board that is quite a bit lighter and you do not have to spend money and time painting it.   

 

If you are going to insulate the sides, I would keep the front of the trailer and 4' of the sides (from the front) at 3/8" - this will provide the majority of the structural support that is needed to keep your trailer from folding like an accordian. If you are going to put the fasterners in the same holes you took them out of, I would add additional fasteners into new holes. I would be concerned that the fasteners may want to loosen up a bit due to the road vibration.     Go with Luan or FRP on the remaining sides and use plenty of fasteners - 

 

For reducing weight - Minimize everything you are hauling.  Do not haul gas until you get to the last reputable station toward your destination. Do not duplicate tools - my bike tool bag and fanny pack hold all of the tools I need for any repairs that can be performed on the trail.  Same thing goes picking up food, water and ice.    I carry a spare front and rear tire as when I need a new one due to a major issue, The nearest place to get a new tire is over two hours away and I usually will need one on a Saturday afternoon when they are closed.

 

You can get a plastic drive on "wedge" to lift one of the axles off the ground when you get a trailer flat - saves several pounds over a floor jack.     If you get creative you can keep the weight out of the trailer.   It is something you need to manage all the time.    

 

Make sure your trailer brakes are adjusted correctly and keep your wheel bearings lubed and adjusted. -  

 

Last September (2016) it was in the low 30's at night for about 5 days and I did not have my trailer insulated - my heater (Mr Buddy) on Low with a couple of  medium sleeping bags made it comfortable.  

 

Good luck with your project. 

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