Cost of a 20" box build out?

rruff

Explorer
What kind of foam did you use?
I'm using PVC foam and no wood now. Previously I used XPS with 3/4" wide wood strips every ~17", and wood around the perimeter (edges). The wood gives you hard points to screw into, which is nice. And you can screw and glue the edges together to construct the box.

With just foam and wet layup, in order to join the panels I had to build a structure to hold the panels in position, then fill all the edges, sand, lay fiberglass inside and outside all the edges and make a big mess (laying thick fiberglass when gravity is pulling it off... sucks), then sand a bunch more. Fiberglass dust is like billions of tiny needles, and it's thick all over you and your entire garage. If I'd cared about hiding all the overlaps and making it look really pretty it would have been a lot more more sanding...

If you aren't cost and weight constrained it's best to just let someone else like TC build the box. You can finish the inside however you want.
 

RoamIt

Well-known member
Thanks for the info. Once I get the measurements I'll get an exact quote from TC. I am also investigating the idea of using a reefer box. Either way, It's a matter of finishing the inside and skipping the whole box building part. I work full time, have kids, and other priorities. I want to avoid this becoming a 10yr project!
 

Alloy

Well-known member
Thanks for the info. Once I get the measurements I'll get an exact quote from TC. I am also investigating the idea of using a reefer box. Either way, It's a matter of finishing the inside and skipping the whole box building part. I work full time, have kids, and other priorities. I want to avoid this becoming a 10yr project!

Reefer is a good idea but keep in mind they require a high floor loading which can mean less insulation. Not hard to work around if a foam (hydronic?) sub floor can be added.
 

RoamIt

Well-known member
I thought about that, some have channeled aluminum floor that may lend itself to being a subfloor. Then laying in a hydronic heating system, then insulate over that(?) Still looking into it. The Mercedes does have a Webasto heater for the cab, don't know if it would have the capacity if I tapped into it, but the idea of just adding another pump and the lines sounds easy(?)

I could buy a used reefer cheap, cut to size, add new composite panels as needed. I actually got a quote of 9K from a company in Florida for a new one, no doors/windows so I could cut openings as needed.
 
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RoamIt

Well-known member
This is the materials quote. I didn't go with it as I want the truck on hand for final measuring, design. I was just trying to get a ballpark cost to see if the idea was even viable. we did go back and forth as they include things as standard that I would not need for the intended purpose.

Complete Truck Bodieslocal 706-538-6321 (no 1 necessary)
21850 Ga Hwy 85fax 706-538-6850 (no 1 if local)
Gay, Georgia 30218Toll free 800-345-6153 or 888-834-1370
CUSTOMER:
ADDRESS:
ATTN:
PHONE:
FAX:
E-MAIL:
11’ LIGHT WEIGHT- REFRIGERATED COMPOSITE VAN BODY
QUANTITY1SHOP ORDER
DATE10/11/2021
QUOTE101121LW11-JP03CUSTOMER P.O.
SALESPERSONJAMIE PURGASON
LW-11'
INT HEIGHT74"INT WIDTH90"EXTERIOR WIDTH96"
INSULATION3" Polystyrene side walls and front wall
REAR DOORTwo (2) Panel Full Opening Rear Swing Doors
Removeable Vinyl Strip Curtain
SIDE DOORNone
FLOORExtruded Aluminum "Hat" Floor, smooth surface
2 Drains and kazoos 1 in each front corner
SCUFFExtruded Aluminum 12" sides, front
LININGOne piece .040 aluminum
EXTERIOR PANELSComposite side walls and front wall
ROOF AND SUBPANOne piece fiberglass (exterior)
GRAB HANDLESCurbside and Roadside Rear
BUMPERICC Bumper
LIGHTING (interior)(1) LED Domelight with switch in rear
LIGHTING (exterior)LED lighting package per FMVSS 108
 

rruff

Explorer
Seems like a good price.

That's an 11ft long box; is that what you are planning now?

Looks like vertical internal structure on the heavy duty models; maybe not on the others.

I wonder if they'd be willing to customize?
 

RoamIt

Well-known member
I don't know the exact length I want yet. I'm trying to keep overall length down, it's going to be a big beast as it is.

One of the design plans I'm contemplating is using one of the crew cab doors as the habitat entrance. I wanted the Doka as I would like to be able to accommodate visitors, and the single cabs are a little cramped overall anyway.

So if I use the Doka space for another 2-3 seats and for storage (probably clothes), maybe another sleeping area by lowering a bed in place from above, a 'foyer' so to speak for coats/hats/shoes. Then I save the wall space in the what is probably going to be a shorter habitat box.

From my conversation's so far, they are willing to customize reefer boxes. Morgan is also one of the major commercial reefer box builders. https://www.morgancorp.com/refrigerated/cold-star/
 

Joe917

Explorer
A couple of observations:
A reefer box is a good start, if it can be customized, double rear doors will be a disaster.
Composite panels are the way to go, home made usually look like home made, professional suppliers are the best option.
Any "living space" in the cab is outside the heated envelope of the camper. Steel cabs leak heat fast.
You probably won't see any change from $100000 budget. (Unless you have very low standards)
 

RoamIt

Well-known member
A couple of observations:
A reefer box is a good start, if it can be customized, double rear doors will be a disaster.
Composite panels are the way to go, home made usually look like home made, professional suppliers are the best option.
Any "living space" in the cab is outside the heated envelope of the camper. Steel cabs leak heat fast.
You probably won't see any change from $100000 budget. (Unless you have very low standards)

That's my experience so far, they can be ordered with any configuration you'd like. The new builds are using composite panels, they bill them as their 'lightweight' options.

Once I went with importing a MB, I knew it was going to be $$$. But I think I can mitigate a lot of cost by prepping the truck myself, building out the interior. My budget is more than 100K(y)

On the heating part, you may very well be right, I may have to install a separate heating system in the box, and count on the existing heating in the cab, along with insulation, to make the cab a valid sleeping area.

But I'll save further comment for when I actually get the truck, take the measurements and more fully vet the reefer idea. It will all end up in the build thread for all to see, comment, advise, and laugh at my crazy ideas.
 

nathane

Active member
I sourced my box walls from a company that supplies panels for refrigerated lorries. They CNC cut panels and window/door cut outs. Total cost of 4 walls for a 4.2mx2.2m box was about $6k. I mounted these in an aluminium frame designed for HVAC plant retrofit installation units made by an italian company called prolam cost c$1,500. I made the floor and roof panels myself vacuum formed with structural PU foam (airex c70) and carbon/epoxy (there were some amazing deals on carbon fabric when the covid thing hit aerospace supply chains leading to a glut of high quality fabric - I stocked up with enough to last me a lifetime so don't know if this is still the case). Floor has an outer aluminium skin.

I did it this way because there was no way I would get a decent quality finish on panels as big as 4mx2m and have them perfectly square and flat. Doesn't matter for roof as you won't see it!

All internal panels and furniture (bulkheads, cupboard walls, sofa, bed frame etc.) which have a maximum dimension of 2.2m x 1m I have made myself vacuum forming onto a home made casting table that acts as a flat moulding surface. You can get a very light panel this way with a very high quality surface finish. It is a slow process though, 24 hours to mould each panel. Building from timber would be quicker, but not as strong, light or environmentally resistant.

I have yet to make the drawers that will make up much of our storage capacity. These will also be composite, but i haven't worked out how to mould them yet!
 

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