DIY EarthRoamer (sorta)... newbie questions

[ReluctantTraveler]

Hi y'all! I've been lurking on the forums for the last few weeks, and reading as many of your DIY threads as I can, and am at the point where I have a few specific questions I was hoping to get some advice on.

As the title implies, I'm hoping to build an EarthRoamer inspired cab-over truck camper (with less lofty expectations).

Background:

I have a family of 4 (plus a small dog), and we recently completed a 3-week trip up and down the US East Coast in a 16 foot interior bunk house travel trailer.

It was amazing, but we quickly realized that a travel trailer doesn't align very well with our preferred style of travel. We like to jump from place to place every few days, rather than setting up camp in one location for a week or two. Having to constantly unhitch, level, worry about whether or not we could turn the thing around if we wanted to go explore something cool we saw along the way... it felt limiting.

And at 7 feet wide, the interior was just a touch too narrow, so we were constantly shuffling around each other on cold/rainy days.

Goals/Wants/Needs:

We aren't looking to do serious off-roading or overlanding. We mostly stay at campgrounds, but we do want the ability to boondock or go a little off the beaten path every now and then.

• 4x4 so I don't have to worry about getting stuck, but I don't think we need a raised suspension, military tires, a super-single, etc. just yet. Maybe in the future.
• 4-season camper, since we'd love to do some winter camping in the mountains.
• Space to sleep 4. I'm looking into bunk beds or a dinette + sofa to full-sized bed option.
• An adjustable suspension system that can be used to level the camper.
• Lots of water, solar and battery capacity for comfortably boondocking with 4 people (most likely at Walmarts or state parks).
• A composting toilet, because black tanks are the bane of my existence.

Plan/Details:

• F-350 or Ram 3500 crew cab long-bed gasser with dullies as the base to get a rigid chassis while maximizing payload (from my research, I can expect about at 7k max payload capacity).
• For simplicity (and the limits of my own abilities and budget), I was planning to use wooden stud framing with plywood interior/exterior.
• I plan to build it on top of an aluminum flatbed, which also provides external storage and lets me maximize internal storage space.
• I'd like a floor length of 11-14 feet, width of 8 feet, and a king-sized cab-over.
• The interior layout would be EarthRoamer LTi inspired, with some modifications for our specific needs.

Quick note: I'm not opposed to moving into something like an F-550 or Ram 5500, but the flexible chassis and need for a subframe make me nervous. Can a flatbed be mounted in a way that it would be a suitable subframe (either 3-point or with springs)?

Questions:

• Is 2x2 the recommended thickness for wall studs (vs. 2x4 like in a house)?
• Do you use batt insulation, hard foam panels, or something else?
• I know stick-and-tin RVs are typically 12 inches on center. Same for a truck camper?
• I'm assuming the floor and cab-over should use a thicker and heavier-duty frame than the walls? What about the roof?
• What do you apply over the plywood exterior to waterproof it? Stain/paint? A fiberglass epoxy? Truck bed liner? A veneer?
• What do you do to the plywood interior to make it look nice and not like a DIY project?
• How at risk of exceeding (or closely approaching) the max payload am I with something like this?
• How far beyond the rear axle can a flatbed safely extend? A 14 foot bed would be amazing, but I can make 11 work if needed.
• How do you mount racks (for bikes, kayaks, etc). to the exterior without compromising the integrity of the structure? I'd imagine 2x2's (assuming that's what you use) support far less weight than 2x4's.
• Anything I'm not thinking of and should be?

Thanks in advance! This place is amazing!

 

[Peter_n_Margaret]

Some random thoughts....
You will be severely weight compromised. Believe that and start with a weigh saving push with every decision from day 1.
20kg of water will be more useful to a family of 4 than 20kg of wood in the build.
Seriously consider fibreglass sandwich panel for superior strength, insulation, durability and weight reduction. If you can build with wood, you will have most of the tools needed and will have no problem with sandwich. It will simply be quicker.
Abandon the twin cab and engineer the house section to have 2 seats that can be occupied while travelling (with seat belts) with acess through to the cab. You gain an extra metre of living space and have lower weight. The seats in the back need to be there anyway.
Abandon the tray. Build directly on the chassis. The final product will be lighter and lower and water will be directly under the floor.
Maximise water capacity. Water determines how long you can spend in a remote spot.
Maximise window area. When the weather is bad and you are confined indoors, the more you can see outside, the better.
Add a removable urine tank under floor for the composting toilet to extend the emptying frequency.
Install a "hydraunic" diesel heater for central heating and hot water.
Maximise solar installation. You can not have too much. Reserve the roof for solar wherever possible.
Cheers,
Peter
OKA196

 

[1000arms]

Keep in mind that everything is a compromise. Figure out what works for you. A fixed wall hard-sided camper may be too tall to fit under some bridges/overpasses, but doesn't require time to set up in the rain or snow.

Go as light as you safely can to minimize the truck needed to carry your camper.

Check in to insurance for your rig before you buy anything. The answers might influence your choice.

With the above in mind, many people easily insure a 4x4 CCLB DRW pickup truck, especially with a gas engine.

Minimize weight far behind the rear axle, but keep in mind that empty bunks while driving aren't the same as putting a 100 gallon water tank over the "tailgate".

2017+ Ford F-350 pickup trucks have a very stiff fully-boxed frame.

Although it would create a tall (but road legal) rig, one could build a slide-in truck camper (from plywood, rigid foam insulation, and epoxy/fiberglass) that has a "basement" between and below the pickup truck bed-rails, with the main body above the pickup bed and extending out to the width of the DRWs. Such a rig could have a tall and comfortable cabover above the cab of the CCLB. Put any water/gray/black tanks, and batteries, in the insulated basement.

You mentioned plywood and wood, so I suggest you look at the (hopefully soon to be released) second edition of Devlin's Boat Building Manual: How to Build Your Boat the Stitch-and-Glue Way, Second Edition or the much older first edition to get you started.



Consider making a frame from plywood. Three pieces of "3/4 inch" plywood could be glued together to allow 2" foam insulation to fit between skinning panels.

https://www.homedepot.com/p/Owens-Corning-FOAMULAR-NGX-F-250-2-in-x-4-ft-x-8-ft-SSE-R-10-XPS-Rigid-Foam-Board-Insulation-52DDNGX/315197962

Look up @IdaSHO 's camper.

Check the following link for a link to GacoRoof and for a link to an image of IdaSHO's camper.

Roof coatings

After a really bad experience with Hy Tech coatings in Florida, I won't be using any of their products anymore so I am looking for an alternative roof coating. Theirs is like many others except they add tiny ceramic balls for insulation. I know I have seen others mentioned on here like Gaco but...

expeditionportal.com

Take a look at Alaskan Campers for possible ideas.

TCM EXCLUSIVE: Alaskan Campers Debuts Modular Flatbed Solution

The Alaskan Camper rig for Overland Expo West presents an economical and highly versatile solution for a flatbed and traditional camper.

www.truckcampermagazine.com

An Ultimate Alaskan Camper Rig

After fire destroyed his first Alaskan Camper, Carl Isner went all out designing his new off-road ready Alaskan Camper and Dodge Ram 5500.

www.truckcampermagazine.com

 

[simple]

For safety reasons, I'm a fan of the crew cab for family travel. Everyone is belted into a crash tested vehicle and there are likely 2 walls blocking DIY bits that would become projectiles flying forward in a crash.

Regarding you comment about a 16 x 7 trailer feeling cramped. For your build are you thinking about a 12' x 7.5' box with an extension over the cab?

 

[ReluctantTraveler]

@1000arms - amazing response, thank you!

Is the advantage of building directly on the frame that you can store water + waste in an insulated basement, resulting in a lower build height? I had planned to put the liquids underneath the couch or a dinette seat.

One of the draws to a flatbed build is that we could jack up the camper and still have a usable truck. Useful when not camping, but also if we need to run to the store while at a site and don't want to bring the whole "house" with us.

Regarding plywood and rigid foam: is the idea to create a "foam sandwich", with the plywood as external and internal veneer, and the foam doing the insulating and sound proofing? How do you join them together?

I also have no idea what this thing might weight. Our 16' travel trailer is 3200 lbs dry, but I know they build those with super light, super cheap materials. Is the 7k cargo capacity of the F-350/Ram 3500 not enough, realistically, for what I'm looking to do?

I'd be open to an F-550 if necessary.

And if I'm understanding you correctly, it's ok to go beyond the rear axle, so long as you most of the weight is ahead of it (particularly while driving)?

@Peter_n_Margaret - Sounds like you think I'll be too close to max weight with a wood build? From what I've read, wood is light and strong (though obviously not as much as fiberglass panels).

How do you join fiberglass panels together? How do you mount cabinets and things to it? Are you just screwing stuff in, same as with wood?

I agree with @simple though: building "while driving" seating in the living space is a non-starter. Even if I trusted myself to mount seatbelts into the frame correctly (I don't), there's no world in which a fiberglass or wood living space has anywhere near the crash safety as a truck cab.

"Regarding you comment about a 16 x 7 trailer feeling cramped. For your build are you thinking about a 12' x 7.5' box with an extension over the cab?"

11x8 floor or 14x8 floor, plus the cab-over, yes. We have this camper right now, and while the floor dimensions are 16x7, there's very little actually floor space. The bunks eat up a huge portion of space, as does the queen bed, and the storage is very poorly though out. The design of it plays a huge impact on the livability, more so than the raw dimensions of the space.

 

[Peter_n_Margaret]

@Peter_n_Margaret - Sounds like you think I'll be too close to max weight with a wood build? From what I've read, wood is light and strong (though obviously not as much as fiberglass panels).
How do you join fiberglass panels together? How do you mount cabinets and things to it? Are you just screwing stuff in, same as with wood?

EVERYTHING will finish up heavier than you plan. No matter what. Once built you are stuck with that weight. A family of 4 will have great demands on space and weight. Then, everyone will want their toys, and fair enough.
Sandwich panel is simply glued together with a good quality simgle pack polyurethane glue like Sikaflex 252 with some small aluminium angles in the corners for extra surface area. There are a few simple tricks for attaching stuff. No screws.
Add the fact that the gel coat finish is extremely durable and lasts decades. Glue it together and it is almost finished.
Cheers,
Peter
OKA196 motorhome

 

[1000arms]

@1000arms - amazing response, thank you!

Is the advantage of building directly on the frame that you can store water + waste in an insulated basement, resulting in a lower build height? I had planned to put the liquids underneath the couch or a dinette seat.

One of the draws to a flatbed build is that we could jack up the camper and still have a usable truck. Useful when not camping, but also if we need to run to the store while at a site and don't want to bring the whole "house" with us.

Regarding plywood and rigid foam: is the idea to create a "foam sandwich", with the plywood as external and internal veneer, and the foam doing the insulating and sound proofing? How do you join them together?

I also have no idea what this thing might weight. Our 16' travel trailer is 3200 lbs dry, but I know they build those with super light, super cheap materials. Is the 7k cargo capacity of the F-350/Ram 3500 not enough, realistically, for what I'm looking to do?

I'd be open to an F-550 if necessary.

And if I'm understanding you correctly, it's ok to go beyond the rear axle, so long as you most of the weight is ahead of it (particularly while driving)?

You are welcome!

The Ford 2017+ F-350 is available as a pickup truck (complete vehicle) and as a chassis cab (incomplete vehicle). The Ford 2017+ F-350 pickup truck has a fully boxed frame, but the Ford 2017+ F-350 chassis cab has c-channel aft of the cab.

The frames are different. In addition, the pickup bed has wheel wells, but a true flatbed (think of the name "flatbed") is mounted high enough that wheel wells aren't needed (this is true for flatbeds designed for the pickup frame and for flatbeds designed for chassis cab frames). Making the best use of your available volume is important, but, how much money can/do you want to spend to get it?

If you make a removable camper, designed for either a flatbed or designed for a pickup truck bed, you have a removable camper. How difficult it will be to remove and install at a campsite? Will wind be any of issue, especially if you make a strong but light camper? Will you feel comfortable leaving the camper at a campsite? Will you want any bathroom/kitchen/cooler/fridge/freezer capabilities if you leave your camper behind for the day?

How big do you want your cabover to be? Many are pretty low, which does keep the overall height down, but really limits the cabover to cramped sleeping height.

Consider the gap between truck cab and cabover to avoid any contact due to flex, a cabover with an insulated floor and roof (and sides), an air gap under the mattress to help avoid mold, the mattress thickness, whether you want to be able to sit up in bed, and how much time will be spent awake in the cabover due to the number of people in a small volume camper.

Consider the above, calculate the height of the outside roof of the cabover, and then consider making the height of the outside main-body-roof the same. Doing so would allow you to put a basement below the main body while allowing a lot of headroom.

Especially with a crew cab, it makes sense to design a camper with a cabover bed, but, with a long enough truck bed, one could build a small cabover for storage and put all the beds down in the main body to keep the overall height down.

Stitch and glue boatbuilding has been going on for quite a while, and many boats are light but take a pounding. Really look into it because it will allow you to build a light, strong, waterproof camper. There are people on this forum making very good use of composites, but, you mentioned using plywood in your first post.

Take a look at Loctite PL-Premium construction adhesive, and at epoxy + fiberglass.

Products

www.loctiteproducts.com

For foam:

Loctite PL300 Foamboard

Bonding foamboard to other materials. Low odor, low VOC formula and water clean-up.

www.loctiteproducts.com

Find a place to "build" your ideas out of tape-marks and cardboard. Test the fitting and arrangement.

Consider a flip-down shower-stall if you will be including a shower, and a swing-out toilet if you will be including a toilet. These can be out of the way as part of the cabinets when not in use.

Consider a couple of twin-XL-mattress Murphy beds, mounted sideways, to fold down into bunks, mounted on the back inside wall. Make them so they can be operated independently, allowing the bottom one to be used as a seat for two. Use a passenger-side entrance just in front where the beds would be in the down position and allow the "hallway" to be a place for TV-trays or another form of table. Keep the "corridor" going to the cabover about 4' wide with cabinets on each side. this will allow for internal space and moving around each other without feeling as if one is in a mosh pit.

Keep in mind that it is a balancing act. Do your best to keep any weight as low as you can, such as water and batteries, and above the the rear axle or slightly forward, but not so far forward that your front axle is overloaded. With a big cabover, a rear overhang can sort of balance it (but keep overall weight forward), which allow for light bunks and open space behind the axle. Just keep in mind that the longer the camper is, the more surface more wind to push against.

Look at marine plywood weights, as well as Baltic Birch plywood if you can get it. You could calculate frame weights and skin weights. Check on epoxy and fiberglass too. Remember, you don't need to make the frame out 4x4s and the skins from 3/4" plywood.

Your cabinets can be part of your structural design to support the roof (and overnight snow).

Make sure everything can be glued-and-screwed to something solid. (Stitch and glue.)

1/4" plywood skins over a frame with 2" rigid foam plus epoxy and fiberglass will be strong and light.

Basement model slide-in truck-campers tend to be taller than none-basement models.

Look though the following websites for any ideas you might find useful:

Extreme Rigs Archives

Extreme rigs features the outrageous world of matching truck campers with Unimogs, Mitsubishi Fusos, and beyond.

www.truckcampermagazine.com

Aftermarket Truck Bed Manufacturers for Truck Campers

A recommended list of the top aftermarket truck bed manufacturers in the industry supporting truck campers. Aluma Tray Manufactured by Overland Explorer

www.truckcamperadventure.com

Check out ShaChaGra:

Ever Wondered What a $171,000 DIY Motorhome Looks Like? I am Speechless.

I've never seen anything like this monstrosity of a DIY motorhome. It's got 4 bedrooms and a hot tub and survived a 20,000+ mile, 16 month European journey.

www.doityourselfrv.com

Shachagra- Family of 5 traveles Europe and Turkey, International 7500

Great threads here, great to see lots of projects. We just finished touring Europe and Turkey in our home built on a International 7500 chassis. Large, 33K, 400 gallons water, 200 gal diesel, all diesel fired (stove, heating) with a 2K W solar array and 2100 AH of Lifeline batteries. The trip...

expeditionportal.com

 

[The Artisan]

My buddy and I built this 2" frp composite 12.4 x 7.4 x 7 weight was 455lbs. Sika 252 14ga angle added 350lbs. My new proto will be premade wetlayed 12k carbon fiber angles. Sold proto and they have been using it and trips to baja etc. NO issues
Kevin

 

[Peter_n_Margaret]

Find a place to "build" your ideas out of tape-marks and cardboard.

Cardboard and hotmelt glue is good too.


Cheers,
Peter
OKA196 motorhome

 

[tacollie]

And 11-ft bed is pretty long.To get a 11 feet or more of floor space you should look at a long wheelbase F450/550 Ram 4500/5500. The good news is you'll have lots of payload. The bad news is you'll have to drive a truck with over 200 inches of wheelbase?

 

[1000arms]

Cardboard and hotmelt glue is good too.
View attachment 720496
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Cheers,
Peter
OKA196 motorhome

Good point!

 

[ReluctantTraveler]

@1000arms @tacollie From what I'm reading here, sounds like I should just accept that I'll need an F-550 or 5500 for this build, given the size I'm looking for.

Love the idea of cardboard prototyping.

@Peter_n_Margaret Thanks for the details on Sikaflex, and @The Artisan, thanks for the example!

I can ask this in the DIY build channel if that's more appropriate, but for both composite panels and glue-and-stitch...

• How do you affix things like cabinets or fold-down bunk beds to the wall? Can you screw into the panels? I can't imagine that glue would hold weight on something like a fold-down bunk.
• How do you mount external load-bearing items? I'm planning to add a full-sized spare and some rear racks for bikes, snowboards, and such.

 

[ReluctantTraveler]

I'm also assuming this is a dumb and obvious question, but this would be my first truck: can you use a flatbed as a subframe and attach it in a way that it can move near the front or rear (I know which end you use for fixed attachments is a hot debate here)?

 

[rruff]

I'm also assuming this is a dumb and obvious question, but this would be my first truck: can you use a flatbed as a subframe and attach it in a way that it can move near the front or rear (I know which end you use for fixed attachments is a hot debate here)?

The mass produced flatbeds aren't designed for this, AFAIK. Just want to emphasize that many newer pickups (not cab-chassis) in the F350 range have fully boxed frames. You can hard mount those and don't need springs or pivots in between the subframe and truck chassis.

Important question... what is your budget?

 

[ReluctantTraveler]

@rruff Based on some feedback above, I think I need to look into the F-550 instead of the 350, based on weight and dimensions. It's been pointed out that I'd be close on max cargo weight and probably pushing it with the wheelbase if I want an 11-14' floor.

And as you already know, the 550 is only a chassis cab with a flexible frame.

I'm still trying to figure budget out, TBH. Not including the truck, somewhere between $20k-40k, maybe? I'm viewing this is an investment in family memories.