Box construction for DIY

[Oakland Mike]

So my thought is that rather than build a box from steel tube (like showhauler) it would be much easier and probably save a lot of time to use a dry van box (like a 26ft'er).

Is there any problems with going this route? I can't think of any. Morgan Van body makes a nice box with FRP smooth sides with a door and stairwell already built in. I have talked with a company that manufactures them close to where I live and if I need to walk on the top, they can put in extra roof bows.

Any comments are welcome!

Thanks,
Mike

[rwrr001]

Here's one that someone did.

[Warpath]

What is going to hold up the cabinets, tv, ect..? Box trucks are not designed to carry weight on the walls or roof, there is no real structure. You are going to need to add steel structure which will need to be attached to the floor frame rails. So why not begin with the proper structure and add the panels yourself. I know when I first started this site, I hunted around the net and found a number of trailer component suppliers who handle the panels, trim, caps, ect.. I would hate to see ya buy a box and then have to dismantle it to add steel(or aluminum)framing.

I did read somewhere in here about a member who was converting a box truck, but have not heard any updates.

Bill

[KAYE RIVERCITY]

.....I'd think if you used expanding bolts on the hat channels that they would stay in place.....after all, a lot of dry vans have hangers/e-track/rings/eyes and hooks to keep cargo form shifting....geof

If you were considering using a FRP body go look at a Penske, Ryder rental truck. They use a FRP body and then inside the FRP they use a Z metal stud. Attached to the Z metal, running horizontal, are woods runners, probably hardwood 1" x 4".

This does create a space for insulation and this style of construction would support the cabinets. Also a cavity for wiring. Wiring cound be run at the top and bottom of the walls using a 45 degree panel to cover it. This is done in some RV construction. One advantage would be by removing the panel you could service, change, the wiring.

In some ways the steel framed body mfrs, Showhauler, NRC and United Specialities, are similar except on the inside of their steel wall studs they put OSB panels. They then glue a metal skin on the outside of their steel studs. The Z studs would be better for insualtion because there would be less gaps in the walls that are not insulated. Tubing creates a air space with no insulation.

The appearance of using a dry van body would be similar to a Renegade. Check with the manufacturer of the body to see if they offer a FRP with a smoother exterior finish. Some of the FRP panels have a rough texture.

FRP is heavy and adding interior studs will be more weight. But steel construction is not light either. You could probably find aluminum for the Z studs. Or you could use aluminum C channel also.

[Oakland Mike]

I currently have a van box on the back of the truck for hauling my drag racing motorcycles and I pull a toy trailer. The box has the wood slats that you mention. I put up 3/8 ply over the wood slats and some wainscoating over that. It seems pretty sturdy, I would not have a problem hanging cabinets on them, especially if they were screwed into the hardwood slats.

I had the idea of possibly putting electrical wiring behind the plywood and along the wood runners. Seems like it would be easier to run and as you noted, easier to access later if needed.

I mean, these boxes have forklifts crashing into them with loaded pallets. Seems to me like the construction would be more than adequate.

Mike

[KAYE RIVERCITY]

....wiring could go into the roof or under the floor and pop up/drop down where you need it. Increased insulation means more comfort and less energy usage which equates to smaller generator and less propane use-also less energy use when pluged into a camp ground system-meaning no brown outs and less blown fuses/circuit breakers....Ideally, use of homeowner appliances mean less overall cost of construction[HOME DEPOT WALMART K-MART HH GREGG-or used]. I don't know about others but I'm less than impressed with RV appliances....they seem very junky and oiverpriced as heell....Look at some of the new "Smart House Systems" they seem better designed and built....just adding a switch near an appliance would in most cases allow you to balance a system in case you run into a 30 amp park....modern housing appliances are much more energy efficient than RV stuff.....geof

[KAYE RIVERCITY]

.....BTW I calculated the insulated space inside my trailer's steel tubing studs which ammounted to 2.75 square feet of non insulated air space.....hardly worth worrying about out of 1200 square feet of R-12+ insulated space.....geof

[KAYE RIVERCITY]

....yes-I was bored that day and it was raining....geof

geof. What type of insulation were you planning to use to get the R-12+?

[KAYE RIVERCITY]

....I use something called R-Max...It's a polyisocynate foam board with facings that are aluminum foil... 4X8 sheets 1"=R-7+ Factor....easy to cut with a sharp dry wall knife-glue in place with Liquid Nails/Silicone and fill in gaps, if any, with spray can foam.....my drywall hangers did my whole trailer in 5 hours.....2 layers thick-after I removed the walls and ceiling-which, we put back as soon as they were finished.....there are newer products that have even a better R-Factor but they are expensive....Reflectix bubble wrap is over rated and will degrade if there is any rubbing in the wall-though I have used in in the ceiling of my Volvo over the drivers area/in doors and along with spray can foam and some R-MAX....not really enough space to be super effective but I had the interior out to clean it and fill all passage ways with foam sealent....I have discontimued the air exchange system in the tractor in favor of forced ventulation as I have a under bunk heater/ac unite which is powered by the Onan Generator on the back of the truck....using a HVAC program I have calculated a Maximum 14,000btu usage out of the 36,000 available.....If it gets that cold or hot I'm heading back home....geof

if building you own ,what size metal studs would you use? and how far about on center? thanks

[KAYE RIVERCITY]

.....what is the side panels made of on your truck Body.....that will determine "Z" channel or Studs and a number of other possibilities...LMK...It's easier than you think!....geof

geof. I did some reading on spray-in-place polyurethane. Very interesting. One big advantage is that it seals much better than any panel type insulation. I believe this is the same thing used in refrigerator trucks.

[rwrr001]

Just found this,

High R Double Sided Foil Insulation: *Out performs R30 fiberglass batt insulation. Preferred over fiberglass blanket insulation in metal buildings. Our most versatile insulaton. Consistent 14.5 R value. Great for all climates. Strong recommedation!
The two layers of reflective foil that surrounds the 1/4- inch closed cell center, forms a radiant heat and vapor barrier.

Key Benefits:

Double-Sided Foil
Vapor Barrier
Radiant Barrier
Class A / Class 1 Fire Rating
Convenient flange tabs on sides
Provides 19 DB Soundproofing
Clean
Lightweight
Very Strong
Saves Money and Energy

http://www.steelbuildingsetc.com/default.asp

A 14.5 R value is very high for 1/4" material, wonder how good it really works?

Spray-in-place polyurethane is good but very expensive.

[KAYE RIVERCITY]

....one of the issues that my partners and I are looking into is the spray in place poly foam business....we have been interested in this for 2 years now and haven't done a damn thing but send for information. I have a 2700 sqft house with SPF walls and combination foam board and fiberglass batt ceilings[R-30 walls and R-60 ceiling]....my HVAC costs are 25% of my neighbors....so the stuff works!....It's already paid for itself in the 5 years I have lived in this house by a factor of 3. Aside from that and the cost which is around $1.00 a board foot currently....the place is so quiet I can't hear what's going on outside-dog barking-[my coon hound]local police car siren on yelp till it's in front of the house....SPF is used in most trailers[reefer] but I use foam board because of the labor cost-I use Mexican drywallers-and bridge the joints with alum. tape that we use in the HVAC department.It has a R-factor the same as any polyisocynate foam of R-7 per inch then add the foil for radiant and air movement....1" foam board is $10.00 for a 4X8 at out cost and we have plenty of scrap....I have contacted the bubble wrap supplier and they can't give me any R-value ASME/ASHRE Certification....though I do use it on duct work at a cost of about 30 cents a linal foot...I have used it in my Volvo over the drivers seat and in the doors for some added insulation and infiltration control...My feeling is it is location specific....I haven't looked into it...the supplier told me not to use it around machinery as the vibration makes it break down quickly....we will see....geof

The foil insulation that you describe sounds similar to the Reflectix brand. This is the type of insulation that Showhauler uses in their units.

I have used Reflectix in some house insulation situations. But I am not sure if I want that as the only insulation.

My requirements for insulation are different than most people's due to where I live. I live at 9,100 feet with regular trips on roads at 11,000 feet to 12,000 feet elevations. We have already had night time lows of 30 degrees. But we are still getting daytime highs of 70 degrees. Depending on the weather we might have snow skiing in 6 to 7 weeks.

[KAYE RIVERCITY]

.....cm:....I wish I could still ski-but the knees are shot along with a whole list of other broken-cracked-mis-aligned parts....so I have to watch it on tv...[which sucks]....anyway your coach will have to be almost superinsulated and air tight to keep your heat even through out and at a reasonable cost-also the isssue of an air exchanger to keep moisture and odors under control...my coonhound gets a little "fresh" in damp weather and I turn on the air to air heat exchanger to freshen up the house-or when I walk back in I start wondering if it's me or the dog?....anyway a system of air exchange will also have to be addressed-but it too must be controlable...Much more than a air change each 3 hours and your heating bill will shoot up....maybe you could just run it with a timer for short periods of time or when you have guests.....Interesting problem-give me a few days to think about it I'll get back to you on it when I have a proposal for you to think about. Assumptions: that the outside of the box is 30' Long X 8'6" wide by 7'6" high will give me a starting point-you can modify from there.....I'll consider both propane and electric heat...geof

[rwrr001]

Reflectix is not good, two layers of alum foil and plastic with air can not do much. High R Double Sided Foil Insulation sounds like it is filled with tiny plastic balls. A 14.5 R value sounds very high for just 1/4" material and the price is close to Reflectix. I would not trust either one.

Check out the tests at: http://www.glacierbay.com/Instresult.asp

Reflectix has an Actual "R" Value of 0.67!

Vacuum Panel insulation has an Actual "R" Value of 24.06 at 1 inch, wonder how much it costs?

They have a Loose-Fill Insulation that is sprayed on, they add a little glue and water to it. This type of insulation is the best for sound deadening. Foam is rigid and it can carry sound threw the walls.

[KAYE RIVERCITY]

....loose fill with glue or without-settles and has issues with moisture and MOLD....we no longer use shreaded newspaper" in walls because of the liability issue.[as per our insurer] Bubblewrap has No ASHRE certification that I have found. SPF and Foam board are the only products that I'd use for Coach building. Spray can foam is good also for small spaces. The issue of noise can be overcome by using "white noise generators"- I use one personally in an electrostatic air cleaner made by Crystal-aire....It's the same thing as a SMOKETTRE for use in bars and restraunts to keep the cigarette smoke form being overpowering....as far as external noise is concerned...pick a good campground that enforces the rules....No noise after 11pm...Additionally limit windows-glass it is like drum head-reflects the vibrations....SPF and Foam board also have fire an smoke ratings which many insulations don't have as the [RVAA] associations are a little lax in enforcement......as far as an insulation that is light weight and limited thickness we have been looking at the space shuttle tiles-but there isn't a manufacture that produces it in a 4X8 sheet that we have found....when there as a market for the insulation we will carry it-as for now your options are rather limited and the most cost effective/safe/durable/installable is SPF or Polyisonate Foam Board......If there is anything out on the market I will have a hundred salesmen knocking at the door....geof