To Sheath or Not, That is the Question

Sheathing adds tons of strength and rigidity to a structure, but also weighs a significant amount, something I couldn't justify if I was to stay around 2000 pounds for the "dry" weight of the finished product. Being a spreadsheet guru, I built a spreadsheet that would allow me to estimate materials

My fellow green innovator, James, helping to finalize the house wrap.

and the total weight they would contribute. Also interested  more in building something that met my specific needs and not too worried about anyone else at the lumber yard thinking I am off my rocker, I took a few trips to both Dunn Lumber, our local lumber yard, and Home Depot to use our home scale and weigh myself while holding lumber. I then subtracted my body weight to get the actual weight of materials.

You would be amazed at how much 2x2's, 2x3's, 1/4" ply, and 1/2" ply vary in weight, and how much they vary compared with "standard" weights one would find online. I likely saved a few hundred pounds by hand selecting the materials I used versus ordering them in bulk. I also took the time to hand select the 2x2's and open bundles to find those that were true and not warped. 2x2's in particular can vary in weight by up to 2 or 3 pounds and many are warped and not appropriate for framing.

To gain the most rigidity possible while reducing weight and giving the interior a log cabin like feel, I opted to flip the traditional framing process on its head and use the interior walls as sheathing. The walls then came together in this order.

Interior - 1/2" or 1/4" ply walls - 2x2 or 2x3 frame - 1 1/2" EPS insulation - Tyvek - Cedar siding

Since 1/2" ply was used on the front end and the roof fully connected to the walls, everything stayed plenty rigid. Near the aft end of the trailer, and where the pop-top did not provide a connection point
between walls, I had to use metal straps (salvaged from a nearby home construction site) to provide greater rigidity.

Steaming the front rad

For the from and rear "radius" and the top, I used moisture resistant underlayment in either birch or a sustainably produced eucalyptus 1/4" inch ply on both the inside and outside. This same process was used for the roof of the pop-top and did require some steaming and then bending to get the right shape without breaking the outer ply.

Sheathing on the interior, metal strapping for strength when using 1/4" ply instead of 1/2", and the original pop-top design.

Take Two - Framing the Front End

Using  the garage wall as a canvas and
a strip of 1/4" plywood to determine
the arc or radius of the front end

This time, I came into the framing process with a more open mind and realistic attitude that not everything might work out as I had envisioned; setbacks and changes are all part of the process. I did take a few weeks to step away from the project and returned to it over the long Thanksgiving weekend with a new motivation from James' helpful guidance.

Cutting the arc or radius

The framing began by reassessing the height needs and coming up with the ideal arc for the front end since this time I would be cutting the arc in 1/2" plywood and would need to get it right the first time! Using a strip of 1/4" plywood, the same material that would cover the exterior of the trailer, I determined the ideal arc or radius prior to cutting the 1/2" plywood for the walls of the front end. Both walls were cut together with a circular saw to maintain symmetry and then trimmed with a jig-saw and sanded smooth. The pieces were fit into place using most of the existing framing from my previous "fail" then glued and nailed in place with 18 gauge 2 1/2" finish nails.

Epic Fail - Framing the Front End

Failed first attempt at framing the front-end.

Often times when reading about people's experiences building Teardrop Trailers or Tiny Houses, it all sounds like roses and butterflies. "It only took me three months!" or "This was the most rewarding experience of my life!", these are not phrases that I used during this phase of the project (writing about this months after it happened). I had built a test wall out of 2"x2" white wood, 1 1/2" EPS foam core insulation, 1/4" underlayment (plywood), some low VOC liquid nails and finish nails. While in concept the test wall worked great, was very strong, and seemed to fit the bill, but it was only successful on the 2' x 4' test wall (which is now the wall separating the bunks from the queen bed).

Trying to use the same process to frame a very unique size and custom arc to the front-end proved to be incredibly challenging...and VERY frustrating!

For one, the low VOC version of liquid nails I used, while a "green" product with good adhesion, was not flexible. With the trailer movement just from walking on the platform in the garage, many of the joints cracked. I can only imagine the damage once the trailer was on the road. So in this instance I deviated from my "green" ethic in the name of strength, longetivity, and safety. Unfortunately, unless I can find a fleixble low or zero VOC product, I have resorted to working with standard liquid nails on this project.

Secondly, using only 2"x2" white wood and 1/4" underlayment for sheeting and structural support quickly became apparent that it would not be sufficient, especially after my good friend James, who works in construction and is remodeling his Seattle Craftsman home, came over for a few beers and gave my structure a shake. His reaction was this thing will get torn apart in a cross wind! THIS was my epic fail and he was right. I had a hunch this was the case, but as I had spec'd the whole thing to be built with only 1/4" rather than 1/2" sheeting, I didn't want to try and comprehend how much additional weight this would add. So it was back to the drawing board, literally!

Fitting Everything in the Garage

Cramped garage before the grand reorganization.

One of the major stipulations from my wife Heidi was that the trailer AND both of our cars would fit in the garage...this was an imperative of the project...not negotiable. The trailer itself fit just fine in the garage, but with a 7' 2" wide platform on top, the garage became a bit more cramped and would only become more so as the walls went up. We are fortunate to have a unique garage with adjoining basement underneath our house. It is a three car garage in essence, although we have never owned three cars, and one side is a "tandem" space. It was one of the reasons I bought the house initially as I wanted a dedicated indoor workshop space and exercise area. With this garage I was able to have it all including a climbing wall in the corner used for working out. Since I needed more space to work on the trailer, I made an executive decision one morning to completely reorganize the garage after realizing that the current configuration was NOT going to work for this project. Especially since I would likely work on the trailer project only between 4 & 8 hours per week depending on what my schedule allowed.

The new configuration moved the climbing wall and workout area to the single bay side of the garage and required that the car be moved out for a full workout or climb, not really that big of a deal. I left a small corner on the two-bay side of the garage for riding my road bike on rollers and accessing weights and medicine balls, the elliptical trainer in the picture above came inside. This allowed me to have easy access to everything accept the garage wall side of the trailer, which once framed would not be an issue as the door faced the opposite direction. If more space was needed, the care on the two-bay side could be backed out, the trailer rolled back about 10 - 12 feet and I would have about 150 square feet of workshop space with the trailer still inside. Quite the luxury for a project that started in October and would take most of the winter to frame before it could be outside in the elements.

Framing the Sub-floor

I can't begin to explain how fortunate I am to have support from my wife and family on this project. My parents have begun to pick up our two girls (4 and 6 years-old) from school each Friday and keep them overnight through mid day Saturday. This allows my wife and I to have "date night" each Friday and gives me 4 - 6 hours each Saturday morning to tackle my new project and any other "honey-do" items that need my attention...luckily we have lived in our house for about 6 years and my "honey-do" list is now quite small!

This weekend I was lucky enough to get a bout of cold but very sunny weather to roll my new trailer outside, grind off the remaining attachments from its days carrying a sailboat, clean off the moss, and lay the freshly prepped base platform in place to cut wheel wells and build the sub-floor.

I quickly realized that there is a bit of a warp in the trailer, but was able to shim one corner an get the platform level after cutting it to size. The platform is framed with 2"x3" studs around the perimeter and 2"x2" white wood at 24" inches on center in the middle which will accept 2" EPS foam insulation in the next few weeks and also support the wiring for both the side/tail lights and interior 120 volt outlets that will run off an inverter and battery charged by solar.

In some ways now that it is real, the trailer looks HUGE, but when I think about my family spending many nights in a row living in this small of a space, it looks TINY. Guess I will have the best of both worlds!

Construction Begins!

Rubberized roll-on truck bed liner paint for an undercoating.

Although I still don't have all of the details worked out, I am ready to begin! I think what makes this project so much fun is that there will be plenty of opportunities ahead to make mistakes, test ideas, and deviate from the plans that have been set in place so far.

The first step is to build a platform that will become the sub-floor upon which the rest of the structure will be built. Since the bottom of the structure itself will be exposed to the elements and bombarded by rainwater and all matter of debris from the road, I have opted to use a roll-on truck bed liner as the under coating for both the base and the wheel wells. It was messy work as the paint is laden with rubber bits that coated my gloves, sleeves, and pants while working, but I anticipate it will give the trailer a long life. I used three and a half sheets of 3/4" tongue and groove plywood to create a base that measures 7' 2" x 13' 6". When it is all said and done, I will have about 85 - 90 square feet of living space inside the trailer and an overall length of about 17' 6" from the trailer hitch to the rear arc of the trailer.

Did I Find a Trailer?

It's ugly, low to the ground, cheap, registered, and exactly what I had in mind

Could it be that I have found the ideal trailer, minus the moss? This showed up on Craigslist for $350 and had already passed the WA State DOT test, received a VIN number and was ready to hit the road. The best part was that it only weighed 350 pounds and had a 3500 pound axle. Most of the commercially available new trailers with a 3500 pound axle weighed in at nearly twice that amount and in some cases up to 1000 pounds...not ideal for a concept that would ideally weight less than 2000 pounds total. I drove about 30 minutes to inspect and decided to pull the trigger...he even dropped off a few days later as I still don't even have a tow hitch on our vehicle! I guess I have actually made the commitment to build something, either that or I need to be committed for taking on an insane project on the brink of winter. I am thinking I need a good project to keep me inspired and out of trouble this winter!