New camper trailer restoration

[Danimal1]

Starting a new camper build for either a 5x10 or 6x12. Presently this boat trailer I recently purchased is a 5x10 but could widen around the wheels and extend the rear to a 6x12. Since it measures 60” between the wheels, I’ll end up losing interior width with the wall thickness for a queen size mattress, I thought widening it would help from losing any bed width and having to trim it down. Adding 2ft at the rear for the galley would give be 12ft for an overall length. Just concerned though about the balance of the trailer relative to the axle location? Have a question about using a 1974 axle and springs? I plan to replace wheel bearings but is it prudent to replace such an old axle and springs with new? I think the GVW rating on this trailer is about #2500 pounds which should be adequate for my build.

 

[saltydawg-TNT]

First for axle location we need pics or measurements.

Next age of springs are probably fine, but they are cheap to replace. Dont replace them yet, build your camper then get it weighed and then get new springs 10-20% more than your loaded weight.

The width, its 60 inches for a reason, most fenders are 9 inches. So 60 + 9 + 9 = 78, that keeps the lighting requirements simpler. As soon as you get over 80 you need more lighting. The mattress wont care if you squish it a little

 

[KCStudly]

... and be careful. On a UT of mine, the state inspector measured 79-3/4 inches.... and rounded up to 80 inches on the inspection form, making me have to add the extra 3-lamp clearance lights. What a dork.

 

[Danimal1]

First for axle location we need pics or measurements.

From the axle to the rear frame it’s 48” and from the axle to the apex at the frame at the front is 84”. I plan to square off the frame at the front. I could come back a foot to 6 ft at the front to get that perfect 40/60 ratio. I’m also planning on a front storage box for battery/electrical and will add some tongue weight. I can also probably project my rear galley back a foot if I choose the 11 ft. length? As for 5 or 6ft. width, I’m leaning towards 6ft. but worried about weight as I’m also planning on standing height inside. My Dilly Trailer’s GVWR is 2060 pounds on 8” tires which obviously I won’t be running. I think the present tires are 12” and will probably increase to 15” which should help my GVWR?

 

[KCStudly]

Gross vehicle weight rating is based on the weakest link, be it tire rating, wheel rating, spring rating, axle rating, hitch rating or trailer frame design. Increasing one does not necessarily increase them all.

 

[Danimal1]

Curious, is there a reason why most camper builds are usually no more than 5ft. I understand this may be primarily weight savings but is it also because aluminum comes in 60” stock to get a seamless roof?

 

[DrewsBrews]

Probably because most standard trailer frames people use come in 4ft and 5ft deck widths. People seem to like having the fenders rather than building over the wheels for aesthetics and ease of build. You can find 5ft wide plywood but I don't think 6ft wide is much of a thing unless special ordered. Though most folks get around dimension limitations by joining pieces together.

Beyond that there are aerodynamic issues the wider the trailer gets as it is not hiding as much behind the slip stream of the tow vehicle, adding extra MPG penalty which can really hurt on long trips. Then you have the additional light requirements, as noted previously, if the very outside dimensions are 80" or greater (including fenders, ect) but I doubt that is much of an obstacle.

 

[Danimal1]

Beyond that there are aerodynamic issues the wider the trailer gets as it is not hiding as much behind the slip stream of the tow vehicle, adding extra MPG penalty which can really hurt on long trips. Then you have the additional light requirements, as noted previously, if the very outside dimensions are 80" or greater (including fenders, ect) but I doubt that is much of an obstacle.

Good point about the wind drag with increasing width to 6ft. Since this will be a long distance rig, as our 6 kids and 13 grandchildren live far away, we need enhanced aerodynamics. Everything so far seems to point to staying with our 5ft width.

 

[DrewsBrews]

Going taller can probably hurt as much too. My build is going to have a 5ft tall cabin which puts the total height roughly 6.5ft on a trailer shaped like a brick. Current tow vehicle is a 5.4l f150 with open bed. Not looking forward to the MPG that combo will get...

Unless I get around to fixing my manual trans Saturn Vue that has had a replacement engine sitting next to it for a year and a half

 

[Danimal1]

Going taller can probably hurt as much too. My build is going to have a 5ft tall cabin which puts the total height roughly 6.5ft on a trailer shaped like a brick. Current tow vehicle is a 5.4l f150 with open bed. Not looking forward to the MPG that combo will get...

Unless I get around to fixing my manual trans Saturn Vue that has had a replacement engine sitting next to it for a year and a half

Originally, I tried talking my wife into buying a tear drop trailer however she doesn’t like the low height and the inability to stand up. I realize it will cost me with wind drag. Compared through to a 20 ft/3000 pound + UL travel trailer, that we had considered purchasing, my 5x10 will be a fly weight. Perhaps this is more reason to cut my camper down to a 5x10. We got 18mpg pulling our popup camper (12 ft. box/2500 pounds) on our last trip to Utah/Colorado towing with a Honda Ridgeline. I realize the popup had a low profile so I expect my numbers my go down with a standee. It would be cool to do a simulated wind tunnel test of various camper shapes and sizes, particularly for taller rigs to find the most efficient shape for the front.

 

[Danimal1]

Working on frame prep and restoration and wondered; what is the benefit to building a floor frame sandwiched with plywood top and bottom. Is this just for insulating or is there a structural purpose? Reason I ask, is that we live in a mild climate and seldom snows in Texas. Summer heat is our nemesis.

 

[DrewsBrews]

I just built a floor on top of my frame. A skeleton with perimeter of 1x4s with 1x3 ribs (all laid flat). Filled in between with 3/4" foam board and sandwiched by 1/2" and 1/4" ply. Though I wont be standing up in it so 1/2" should suffice for me.

Encapsulating the frame might potentially gain some small bit of drag reduction by preventing air from catching on all the frame bits. Or I suppose for some sort of protection for any delicate items installed underneath. But I suspect it is most practically used to create some hidden storage in the floor.

Pretty sure I've seen some folks just glue foam board insulation to the underside of the floor within the frame and coat the insulation and any exposed portions of the floor with tar or bed liner to seal moisture from wicking up into the floor... omitting any skin on the underside of the frame. As long as the frame itself has sufficient support for floor underlayment that could save some weight and additional height by not needing additional wood framing to support it.

A big reason for insulation in campers is moisture reduction. It is a small space and the human body expels alot of moisture. It will condense on the walls and floor typically overnight due to the temp difference. Not fun to wake up in being dripped on or in a soggy mattress. vent fans do help, though I imagine it is an uphill battle with no insulation. You obviously wouldn't need to go overboard on insulation due to your climate and comfort level, but some is helpful.

 

[Danimal1]

A big reason for insulation in campers is moisture reduction. It is a small space and the human body expels alot of moisture. It will condense on the walls and floor typically overnight due to the temp difference. Not fun to wake up in being dripped on or in a soggy mattress. vent fans do help, though I imagine it is an uphill battle with no insulation. You obviously wouldn't need to go overboard on insulation due to your climate and comfort level, but some is helpful.

I recall reading about moisture relative to tent camping. It comes from the ground and not from above like dew or rain. Therefore insulating the camper from below sounds about right. Wonder if Tyvek might work well as a moisture barrier too. Since I’m on my frame restoration these things need to be considered now.

 

[Danimal1]

A question regarding building an insulated floor to mount to my trailer frame. The frame measures 53 3/4” wide between the wheels. The frame is backset from the wheels about 3 1/2”. I’d like to build the floor out over the frame about 2 3/4” and obtain an overall exterior width of 59 1/4”. I considered using a 2x6 base plate to wrap around the perimeter in a plywood sandwiched insulated floor and bolt to the C channel. It will cantilever the 2x6 over the edge of the frame 2 3/4”. Is this structurally sound or should I weld outriggers and keep the floor system totally supported at the perimeter?

 

[DrewsBrews]

IMO using 2x6 would be adding alot of weight. Running the board down lengthwise is using the weaker direction for the grain. Id suspect 1x boards oriented laterally would be able to handle the cantilever forces since it would be perpendicular to the grain. That is typically how any cantilever structure is built. Should be less weight too.

I must admin I am somewhat going against my own suggestion on my build as I used 1x boards running down the sides uninterrupted, though the overhang is only 3/4" and the front and back perimeter boards are running full width to support the wall at the corners with the perpendicular grain.

 

[Danimal1]

IMO using 2x6 would be adding alot of weight. Running the board down lengthwise is using the weaker direction for the grain. Id suspect 1x boards oriented laterally would be able to handle the cantilever forces since it would be perpendicular to the grain. That is typically how any cantilever structure is built. Should be less weight too.

I must admin I am somewhat going against my own suggestion on my build as I used 1x boards running down the sides uninterrupted, though the overhang is only 3/4" and the front and back perimeter boards are running full width to support the wall at the corners with the perpendicular grain.

Good point at installing 1x6 boards perpendicular. I thought perhaps a 2x6, though heavier, would be beefier/stronger and could resist the 2 3/4” cantilever. The 2x6 or 1x6 is still nearly centered over the frame where it would bolt up so it’s not like the entire 1x or 2x is hanging out in mid air. So you would recommend 1x6’s clad with plywood. What thickness and type would you use top and bottom?

 

[DrewsBrews]

I'm not saying it wont handle it, just that it is a very heavy way to get around using the wood in it's least strong orientation.

At every point in the build It is rather important to be sure there is not a lighter option that will work just as well. Otherwise it is easy to wind up with a very heavy trailer for it's size.

Floor ply thickness.. depends on the design/materials and intended use. Im not sure I have enough experience to answer it well enough. I used 1/2" bcx and that seems a bit more flimsy than a hardwood ply (very $$$ in my areas so I don't have much experience with it). But should suffice for non standing purposes. If building a trailer to stand in, that concentrates your body weight more so thicker/stronger material would be prudent.

 

[Danimal1]

At every point in the build It is rather important to be sure there is not a lighter option that will work just as well. Otherwise it is easy to wind up with a very heavy trailer for it's size.

Thanks for your thoughts on this and I see your point about weight as an issue. I own and operate a foundation repair business and I’m so used to using pressure treated 2x and 4x material. My build is a standee so I may need to go thicker on the floor since my wife and I will both be standing and moving about around the inside galley. I think 1/2” plywood would be adequate for the top floor if I had enough wood blocking and used foam insulation. Perhaps the bottom ply could be 1/4 or 3/8”. Quarter inch BC plywood from the big box stores is interior grade and not sure I want it facing down in the rain and moisture? I realize it could be coated with undercoating but not sure it’s not 100% protected from wood rot or delamination. What are your thoughts about the bottom ply on an insulated floor?

My pop up camper didn’t have an insulated floor and also wasn’t undercoated. It looked like a treated OSB single ply floor. On a pop up forum I visited, there was much discussion about not coating the floor to waterproof it but to leave it like it came from the manufacturer so it could dry out without having moisture trapped and rotting out the floor. So, I’m scratching my head on what to use for the bottom flooring and if it should be sealed/treated?

 

[rjgimp]

Remember, you aren't building a house here. I think you might be very pleasantly surprised at the strength and stiffness of a sandwich floor framed with 1x2 with 1/4" plywood skin glued and screwed top and bottom and the cavities filled with rigid foam. Resist big dimensional lumber like the plague that it is. You'll end up with a 4500# trailer before you even get all your stuff in there.

 

[Danimal1]

IMO using 2x6 would be adding alot of weight. Running the board down lengthwise is using the weaker direction for the grain. Id suspect 1x boards oriented laterally would be able to handle the cantilever forces since it would be perpendicular to the grain. That is typically how any cantilever structure is built. Should be less weight too.

Thanks buddy, I need to think UL on this build. I’m leaning towards making this a 2” Foamie to really lighten it up. Still undecided on making it 5 or 6 ft. wide? With foam I can go wider without taking a big weight hit. Just not sure about the increased wind resistance since this a higher profile standee at the rear? As for the the issue of cantilevering the floor over the trailer frame if I go with a 5ft build, I’ll just weld outriggers out to have positive contact between the floor system and trailer frame.