My first TTT build from San Antonio

[Stainless 2]

Hello everyone! I am a newbie here, and really wish I had found this forum earlier. That being said, I am going to post progress pics of what I am now calling my prototype TTT, after already getting a ton of new ideas from scrolling the forum for the past couple of weeks.

My build started life as a Skamper pop up trailer, purchased for a couple hundred bucks because the lift mechanism had issues. I was attracted to it because it was already a lighter weight model, and had the wider 20.5 x 65 x10 wheels and tires rather than those narrow ones I was commonly seeing. I plan to use it primarily on the beach at PINS, and the pop up I rented and took out there on much narrower tires only made it about 5 miles down before I felt like I was going to bury it to the axles in the soft sand.

My background is construction and mechanical, so I decided to strip the Skamper to the frame and start on a TTT more suited to what we wanted, rather than have to go through the set up and take down of a pop up. Also the canvas replacement was going to be a pretty penny...lol

Please allow me to preface this by complimenting the many fine precision builders here. I may one day develop the skill sets that allow a very fancy build one day, but my modest project is the one I have in front of me I have used what knowledge I do have to get to this point and will continue until completion this year.

[Stainless 2]

after waterproofing with the fiber asphalt coating on the 3/4" t&g flooring, I decided to use 20 gauge steel framing for weight savings over wood. I had a basic plan in my head of what I wanted, and am shooting for 1000 lbs dry, and $2,000 total budget. I will likely surpass the budget # a bit...but not by too much i hope.

[Stainless 2]

I have used these materials in some commercial projects in the past. I immediately recognized that the challenge was going to be to keep the framing stable as I filled it out into what was to become a solid structure. I made use of what nature had provided me and stabilized the framing by suspending it from the tree, and using some temporary stringers to hold the structure in place as it was filled out, becoming more stable with every components added.

[Stainless 2]

I ordered some sliding windows from a supplier on Ebay. I also knew where I wanted my galley, and where the bed/dinette was to be located. This dictated where the door opening(s) should be placed.

[Stainless 2]

Test fit the windows, and they fit like a glove on both sides. They are centered over where the bed/dinette will be, and hopefully be able to provide some nice cross drafts across the sleeping area. I continued to stiffen up the framing as I went.

[saywhatthat]

Great start. Far better than any weld alum. frame. They never reheat the frames so there a brittle spot at ever weld Are you going to box your studs at door And windows? Why did you not use pop rivets as screws can flex and back out?

[Stainless 2]

I continued using stiffening components to tie the entire frame together. Once it had no movement in the frame whatsoever, I enclosed the wheel wells with galvanized flashing. I left approx 6" of clearance for uptravel, but I dont anticipate taking this one anywhere where it needs to be really articulate.

[Stainless 2]

I used screws because that is what I am familiar with. In hindsight, and if I decide to use this material again, I will likely use pop rivets as suggested. This would also solve the challenge of my sheathing material clearances in some areas, as the rivets are about a third of the profile of these wafer head screws. I am gratified that a majority of them are trapped behind the sheathing and under the roof decking, hopefully helping to deter them from loosening.

[Stainless 2]

Here is where I imagine it is going to get a little controversial. I decided to use 1/2" OSB sheathing with radiant barrier. I designed the layout in my head so that the front face would shelter the edges of the sides and roof. I am using the same fiber asphalt coating along the bottom edges of my sheathing to seal it.

My game plan from the start was to use Bondo on the exterior to cover/conceal the pocket hole joined edges of the OSB (with a squashed bead of latex Alex caulking for good measure) and the countersunk screw holes/heads, as well as any voids left from the fasteners under the sheathing, and my own voids from blade width and/or other small (under 1/16") inaccuracy from freehand cutting of the material with a skilsaw. I will likewise smooth any larger voids in the surface of the OSB that I feel will not be concealed from the finish of my choice.

I used the same TEKS brand screws that I used to attach the 3/4" plywood flooring to my trailer frame to attach the sheathing to the body frame. Because the body frame material is only 20 gauge, I used a lot of them...for all sides and roof which is a double layer of same material with no overlapping seams. After some research here, I will likely use "the mix" (thinned spar urethane to saturation) along all the other edges to seal them prior to my planned finish material.

[Stainless 2]

I intentionally left some overlap at the roof overhang and the front wall that I will trim down to flush with a fine blade jigsaw, then finish with my electric planer. I must add here that I used the "factory" edge at all seams possible while not incurring too much waste. This was another reason that I decided on the OSB, as it is very cost effective. The last reason why I chose the OSB is that I used it as a "shelf/flooring" material along the 2 side edges on my home built LJ Jeep rack to support Rubbermade type tubs years ago. I left it unfinished because I was considering replacing it with expanded metal at some point in the future. The unfinished OSB has held up suprisingly well in my South Texas environment to this day, even though I stopped using the rack regularly when I did not have to haul ladders for work any longer. I may post up some pics of the rack at some point later, as it may become a reference for the roof rack that will eventually grace this project.

My planned exterior finish will be a thick elastomeric roofing paint over thick block filler primer. I am familiar with both of these products, albeit not together. The research that I have done indicates that the elastomeric should have no problem bonding with the primer, and the thicker materials I hope will help conceal the natural voids and inconsistency in the OSB surfaces that do not get any Bondo. I will reference the "Eggbert" build, though I cannot currently attribute it properly to the builder. His success in using the elastomeric finish over what I believe was a similar substrate was what pushed me away from using PMF. I do have other weatherproofing steps which will be revealed in the process that i believe may help improve the performance of the exterior envelope.

[Stainless 2]

I used the window to create a posterboard template to transfer the radiused corners to the sheathing and cut with the same fine blade jigsaw. I test fit the window before proceeding in case I screwed it up and had to start over on the first side. The windows did not come with an inner ring, nor does it appear that the windows themselves have any accommodation for this kind of fastening system. I will be seeking advise/feedback on installation ideas in a separate area of this forum, but my initial plan is to use 1/8" lightly countersunk bolts to suck in the 4 corners in the frame of the window squishing 1/8" butyl tape. The rounded corners are cut with close enough clearance that I have to shimmy and tap the windows into the openings allowing a very snug initial fitting. My plan is to use larger fender type washers inside these corners as well as a lock washer and nylock nuts to deter them from loosening. My next post here will show some window details, although this will also appear in a future thread in the windows area of the forum if I do not land on an alternate mounting solution here.

I feel the need to add that I am very open to comments/suggestions or commentary on my choices of materials and methods, but as you will see in short order, this project will continue with them as I am about 80% complete with my exterior. My hope is that this project will be one of two things. An epic success that will get me many good seasons of camping trips, or an abject failure that will be a great example of what not to do. Either way is a win for me, as this is now a prototype first build...lol

[Stainless 2]

Here are some pics of the windows. Anyone familiar with them are invited to make suggestions. I do not know if I got suckered into buying substandard stock, but they were about $85 each sourced from an ebay seller who had several listings of different sizes, and a great seller rating.

The construction of them seems pretty high quality to me, although I cannot identify a mechanism to lock them in any open position, so I may have some fancy prop sticks if I cannot fab up some other option.

[Stainless 2]

I decided that I would only have 1 door for now. My rudimentary weatherproofing plan will be on full display for this and the rear galley hatch in short order. I do have the option and materials for a second door opposite the first as the opening is framed to accommodate it.

The radiant barrier is already proving effective. The temperature inside is nowhere near as high as I thought it would be considering the 100 degree plus weather and the full sun that it gets starting around 1 pm in my driveway.

My plan is to use 3/4" foam board mounted flush to the interior walls/ceiling using a poly type netting and spray adhesive to allow a 3/4" air gap between the radiant barrier and the insulation in the walls. I decided at the beginning that the floor would get no insulation as even the coldest environment I plan to see will be brief, and cant see the need for it (until I do in the real world)...again prototype...lol

[Stainless 2]

So, upon spending even more time reading in other builds, I feel like I want to delete everything and wait until failure or success. This, however, would not be in the spirit of what I am attempting with this. I haven't found another build like this yet, and so here I am. So I will continue, good, bad, or someplace in the middle.

I decided that the doors needed to be built with a more stable and structurally sound material than OSB. They will need to hold latches and hardware, and need to be stiffer on their own without framing incorporated easily to accomplish this. I landed on 1/2" sanded plywood for the outside "skin" to anchor the hardware to, and have an inner layer of the radiant barrier.

When faced with the rear door for the galley, I tried six ways to sunday to figure out a rock solid, stable, and wide enough frameout with the same material to take the door, which on it's own feels like it weighs about 90 pounds with about 3/4 of the OSB attached at the bottom, leaving the top open to figure out my hinge. I decided I would use 2 x lumber, as it fits perfectly into the metal channel, and will provide a more workable surface than the 20 gauge steel when dealing with the sealing surface. I was inclined to use a thinner collapsible tube type of seal for the door surround, or the ribbed type I had used on my "trunk" in the jeep, which is a smaller steel Job Box that rattled horribly until I isolated the lid with this dampening material. So I laid in 2x4 framing into the channel to attach the hinges to, and be the jamb.

[Stainless 2]

I found these hinges that I thought would be a good fit for the weight, and still allow some room above for a drip edge solution to try to keep a majority of rain away from the opening. Attachment was rock solid sandwiching the 2x4 betweeen the 20 gauge and am able to get some really good torque on the hardware with the bolts pictured. As with most all of the project, I am doing this as a 1 man show, so creative use of a floor jack and clamps came into play again to support and help center the door into the opening while drilling and installing the hardware. I am using larger wood screws on the door side for now, but may change that over to bolts depending on how it performs. I will let the door hang for about a week in a slightly open position to see if the hardware holds up, or the door decides to deform in any way. It will all be coming off again when I flush up the roof edge, and do my bondo and finish work.