Material costs and compromises

tirod3

Active member
We like to build the best we can, and this is the reason for moving away from "stick and tin" fabrication toward better methods. One of the constraints, of course, are costs. The better materials are typically priced double, to get double the performance. Why that happens is another subject, we have to deal with the reality of pricing as available. The work around for most is to literally do it ourself - manufacture what others buy complete, such as prefab panels.

Insulation, for one specific material, gets difficult to justify, especially when an RV is used as a three season habitat. Deep winter, as recent users have discovered, isn't the best application for a thin walled mobile domicile with no foundation. If, when constructing it, we choose to use insulation with twice the R value per inch, we'd likely prefer R6 vs R3. if that insulation is also highly water repellant/resistant, has excellent sealing ability, and adds rigidity to the wall while also gluing itself in place filling every nook and cranny, so much the better.

I ran the math and a small squaredrop with about 400 square feet of surface area could cost $1,000 for a DIY application of 2" spray closed cell foam. How many camping days would it take to recover the cost vs the higher heating expense for a cheaper R value? That app isn't out there for us. It takes pencil work. Off the top of our heads, a longer time than we may want. Some would accept a lower R value knowing the few times they needed more heat they could simply turn up the "furnace" and do ok. It then gets into which fuel and it's cost perform sufficiently well. Having gone thru that with propane heaters and gas powered gensets, lessons learned lean toward diesel heaters and propane gensets. Modern life returns results we don't expect when you do the math. We compromise when money is involved.

Same problem for floors. We can build a non wood upper shelter. But putting down a subfloor on the trailer joists and not using a cellulose based sheeting is darn near impossible. Subfloor = structural sheeting that spans the space and which supports the top layer we tread on. It can't sag or cause the upper surface to detach, crack, separate, etc, all while holding things together. Being highly water resistant is another factor, and low weight, too, or we'd just pour concrete and tile it. In this case, it's a matter of the materials industry simply not offering much in the way of an alternative, and the few I've found in marine decking don't have a quick return on the cost. Things like aluminum extruded snap together planks or fiberglass grating get pricey for a DIY, even with the small footprint, much less aluminum step tread.

Strangely enough, synthetic decking at the lower end is now competitive with treated lumber. Who knew? Five years ago treated held a price advantage. I've got a trailer to redeck (over expanded metal) and running the numbers shows synthetic has the advantage resisting rot, etc. Oh, wait . . . Is that my answer to subflooring?

We balance our desires with our budgets. We accept the compromise to accomplish the job - getting out on the road for the weekend. We enjoy the RV while we can, knowing it has a limited life because of its inherent weaknesses - just like the vehicle we tow it with.
 

Fenderfour

Active member
I used Coosa Board for the floor and bed platform of my camper (link to build thread). It's much more expensive than plywood, I think it was $300/sheet. It wouldn't hold up to heavy use like a utility trailer deck, but it seems to be great for a camper floor. I insulated under it with XPS board and spray foam, covered that with filon.

I spent a lot of time cruising marketplace and craigslist looking for cheap composite decking, but never found something that I liked.
 

tirod3

Active member
It's easy to spend hours trying to find products that don't exist. I've yet to find a copy of "All you need to know about women". I have found a lot of answers right under my nose, tho. Flattened expanded metal as a subfloor is what thousands of utility trailers use. Thin, strong, cheap, what's not to like? Fairly lightweight considering it's 40 - 60 % holes. There's a lot of retro tech that works, it's the leading edge ultralight that they charge an arm and a leg for.

While not a great deck for rough use, there is a 'redeck' synthetic plank that goes over old wood decks. It's pretty inexpensive, thinner and lighter weight, and wouldn't look bad as a flooring in a small squaredrop. Getting an idea of what size/part number for the expanded is the real trick, like a lot of other stuff, the internet is saying less these days. "Call for your quote."

A lot of "great leap forwards" have often been a new combination of existing materials that simply haven't been tried yet. As I was typing that it came to mind that corrugating expanded metal would result in handling heavier loads, and in aluminum could be "inexpensive" because it used less. Searched and its out there.
 

6912

New member
2" spray closed waste money use sheet sealed with can foam
Do you want a trailer that is going to last for a couple of hundred years the easiest way to build I mean there is no easier way .
Goes together like the Legos . Well first of all you have to get away from the b*******seems people are racing to the bottom . Wood will rot The FT owns 9 RV repair shops.
Most trailers now that we see coming in that are the biggest pieces of garbage are made from a steel frame with aluminum bound type crap on the outside. Aluminum bound crap gets ripped easy . it gets condensation that depending on your insulation you're going to get black mold.
A way to build a trailer that is going to last for a long time is look at an aluminum semi-flatbed when it is empty you see that bow in it well that pushes against everything and every direction when it gets weight on it .
You can do a hand laid panel you do it in two stages with REAL fiberglass with woven and you get the same effect. As small as these trailer are no bs frame in the pod.
We have built trailers that have been rolled off of a cliff ,rear-ended on the freeway and just a little bit of repair going to Walmart again it seems like everyone who is building a trailer now is a race to the bottom. .If you get a fiberglass skin that is on a roll it is weak crap. We use Home Depot foam ploy resin .Any fool that tells you cant use H D foam and ploy resin is full of ############## . YOU use $12 hardboard as a mold . you have to do your lay up in 2 parts to put panel under load. We do a 5 by 9 one inch foam
about $ 125 about 85 pounds per panel. the pod 190





sm6.jpgtopband1.jpgsm6.jpgtopband1.jpgIMG_20220110_163942 s.jpg
 
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6912

New member
so easy cut sides add FIBERGLASS angle let set 5 days come in with can are poar foam . seals and blows up inside and outside the FIBERGKLASS skeleton frame. No gap to let heat out are water in.
sm6.jpg.See the lip on side wall . So easy made with saw foot 1.5 inch . You set front ,back and top panels on. doing doors and jams out of real fiberglass about $35 US for the blank . Remember no BS frame. Using a frame waste of time Frame will stop this way of building from working go try to smash a football same thing


IMG_20210514_195808.jpg to make real fiberglass angle get alum. angle 4 feet are so we use 12 feet. NOT iron. add clay down center shape with a quarter 25 cents to get a rounded edge.we like 2'' by 3'' with 3'' on top helps with bow in panel.
IMG_20211218_133159.jpgsm.jpg
 
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tirod3

Active member
Which foam are you currently using? I searched and of course every one Home Depot sells came up in their listing.

That's better than Menards search engine, which seems to lack tolerance for synonyms and descriptions for products. I can type words from the page headline and it won't show. But, it's worth the work as they have products locally at better prices. This is part and parcel of modern materials, getting search engines (and google) to cooperate and working with suppliers as best we can.

There is, of course, the danger of "you get what you pay for" chasing down economy. 24 ga steel vs aluminum has a price advantage yet you offset costs with more weight. That's where priorities come in and what works for some won't for others, including cash flows. DIY helps knock down labor costs, material selection is where we make choices and our experience working with them tilts the scale. I see a lot more using fiberglass and foam these days, it's an attractive alternative.
 

6912

New member
We use isocyanide foam and ploy resin but if you're just using sheet foam to save money over the spray foam you can use any foam.
If you're trying to save money think about how it is to weld up a metal frame wasting time and money How it is to put a piece of plywood in there that has an r1 value and eventually will rot . They may not rot in the next 10 years but guarantee it will rot .

So again think about the money you would be wasting building a frame the time when you can build something that's damn near indestructible. can be outside year-round IMG_20211102_180503 (1).jpgIMG_20220129_164311.jpg
 
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tirod3

Active member
In terms of insulation, Im looking at what will deliver 3 season performance on a sq ft basis. Same for wall construction. It also goes to experience with the materials - trying out something new and making critical errors vs "oops I can fix that" has a lot of value. And looking thru builds online, every project has a mistake. I think I can keep the spindles right side up.

Current thinking is using EPS in the floor and vertical walls, and iso foam in the roof, to gain the proper ratio of R values while accepting that this is a 3 season RV, not an Arctic shelter getting towed to Nome dead of winter. Seems there is a lot of that going on yet the point of mobile habitat would be to do the opposite. Any shortfall in heating a diesel heater could cover.

I have a large grid pad to draw things out and add up costs now, which can occupy bad weather days not working on refurbishing the trailer or home chores. On a Limited Budget competing with a kitchen remodel, choosing a building method that lets me pay as I go has a priority.

Nope, Im not welding it, steel studs are lighter than 2x3 stick and w k braces etc it will be tough enough for light off road work w a straight axle under it. The trailer has to remain a functional utility with angle iron sides. I already have it, so this is a lot like a slide in truck camper, 5x8 base, 7x9 upper.

Compromises.
 
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Teardropper

Well-known member
for a DIY application of 2" spray closed cell foam.

To me, it makes no sense to use spray foam. It would just be a mess to clean up.

I find 2" of foam board in the ceiling and 3/4" of foam board in the walls and floor to be plenty. And that's in the middle of Idaho. Even on chilly nights, you need to crack open a window and the ceiling vent, or the humidity and CO2 will become uncomfortable.

4ibzIOs.jpg


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This was Sunday morning. You can see the spar and ceiling light location.

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Design in a spot for a Propex heater and save your quarters.

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They are tiny, quiet, and use very little electricity, unlike the diesel heaters–and have a thermostat.
 

tirod3

Active member
Spray works well, depending, and that has a lot to do with the scale of the project. it's why I downrated it, ie, a compromise. Homes have been getting sprayed for a long time, my 70s A frame home is. Now its common, but the scale of the job on 26 foot bays is considerably different than a 60" camper wall. There's plenty of demand for large projects - which begs the question, why not use it in production of trailers, instead of hanging cheap glass that sags etc? I think what is slowing progress in RV's is an underinformed buyer and cost resistance at the maker level. We simply haven't asked for better and proved our interest by purchasing units that support our demand. The Off Road RV segment seems more amenable to that.

In other builds online, I do see panels sealed in place with can foam, which does help with infiltration and corrects some more hastily cut panel installs. It's fixed and no longer an issue, hard to fault as the final product retains integrity. That compromise thing.

I've noted American DIY tend to focus on a lot of craftsmanship in areas that don't return on the man hours of labor. There are brag threads on reloading benches in work areas that have a lot of fine cabinetry, finished woods, etc. Many are impressive. I tend to see that hobby in light of how it's done in actual ammo plants - it's kept sterile, non sparking, and industrial, similar to my experience in .Gov RV's training in the field.

Low bidder wins the job while meeting specs. We need to specify goals and work toward them thru accepting certain limits in our finances and skills. What works for some may not for others.

And buy the way, diesel heaters are a well developed commodity overseas, they are tiny, they are quiet, and they also use very little electricity. Again, the scale of output is where decisions are made. What works better for under 200 cubic feet of space may have different final decisions for over 325, or 1700. And diversity of fuel on hand can be either an advantage or hindrance. Propane adds to the humidity level unless all it's exhaust is ducted out, diesel is dry heat, recycling the interior air to a large degree. Either way, fresh air intake is required.
 
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Ozarker

Well-known member
Reading some of this hurt.

Expanded steel will stretch and gets wavy.

For DIY, one off projects, your search for materials on a tight budget should include trips to salvage yards. Not suggesting you cut the front end off of a '55 Pontiac station wagon, but consider what you'd like to use, then who uses it in something else, then is that available as salvage?

Flat, insulated aluminum panel; you'll find them in refers, refrigerated semi-trailers, the doors already have a lip around all edges that may attach to a frame. Fill any holes, apply bed liner, paint, cover the interior with thin ply or coroplast, whatever.
Industrial storage boxes were at one salvage place back in the day, they were aluminum, looked like 4x4x8 insulated boxes where the top lid opened up, like a big ice chest. I lifted one end myself, not real heavy, I thought of taking it home and putting it on my utility trailer, wouldn't take much to make a shelter, might turn it on its side.

Just suggesting you think of what material you'd like, then find out who uses it for what and see if you can locate items you can salvage or modify.

Moving on; how many cold days will you be camping, even if caught in an emergency? I've slept under canvas at 52 below zero F, in the Army, diesel heater blasting away, we were warm enough to strip down and go to bed. You aren't in your full time living environment (even if you are) you can make up for the lack of insulation by cranking up the heat source, most likely the cheapest way to go.
 

tirod3

Active member
The deck on the trailer is off now, I had 3/4 treated ply on it and the metal is fine. Its a coarse diamond and reports on that size rarely have issues other than point loads like tires - which are rare on a 5x8. A Cub Cadet would be a tight fit, neighbor hauls his on one similar no issues. I put a lot of bulk on it so a solid floor with sides gets most of of it home.

I did consider box van panels from a delivery, discovered there are none locally as everybody scouring the market here snaps them up for reuse and the prices are high. Zilch commercial salvage or wrecks, even. The VHB tape is difficult to deconstruct - its literally too good. Industry reports on early testing showed aluminum frames cracking at the welds long before the tape fails because it gives just enough. Those box vans also take money up front, I feel stretched already with a trans replacement on the truck.

Heat, a 7k btu diesel heater also crossfits as a basement heater in a pinch. Ran two 20# grille tanks one winter keeping the pipes warm at 5F with 20mph winds. A diesel would take quarts over the same period, plus no open flame. I hear a small one running at medium doesn't soot up like a larger one idling half the time.

Compromises. I can screw together a steel stud frame, mess up a joint and just cut it shorter for bracing. Screw up a panel and its $$$. I can redeck the trailer in "overdeck" planks cheaper than 5/4 boards or ply, the frame and expanded metal already take the load, the decking spreads the point contact to prevent hammocking. And it goes down with Teks for wood on metal, self driller/tapping. Sure beats carriage bolts.

I'm repainting the trailer from rusty black to Farm White, should the axle be Ford Blue or Fire Engine Red? (What is it about contrast colors making things look like Dakar Rally support?)
 

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