Designing the shape

There is no one standard shape for a teardrop trailer.  Some exaggerate the 'tear' shape, some are more swoopy and rounded, some are more boxy and everything in between.  We found we liked the more simple, traditional style shown in our design post.  Since we aren't working from a plan, I decided to use a design principal I learned in college I never though I would find a practical use for - the golden section!

Diagram from my favorite architect guru - Francis D.K. Ching

Sure architects supposedly use this and other fancy design ideas (don't forget the Modulor Man!) - but I have yet to work with one who utilized any outside of college and studio.  It's really all about eyeballing it and using standard lumber/framing sizes. Anywho, for me though, this worked really well for easily measuring out proportionate arches in cad that could be translated onto plywood.  That and I made my math whiz Dad very happy :)

Step one was to layout my 4'-0" x 8'-0" sheet of plywood in cad.  I snapped a guide line 3" up from the bottom to account for the floor system (this actually should have been 1 1/2" because the design changed from when I drew this out - but I decided to leave it 3" anyway).  I then drew out a 3'-9" square.

Next I drew a circle with the center at the midpoint of my 3'-9" box.  Where the circle intersects the line I snapped 3" up from the bottom will be the start of my next rectangle.

To finish drawing out my next rectangle, I drew a line from the intersection of the circle to the top, right hand corner of the 3'-9" square.

Next, I got to draw my arches.  The larger arch has the radius of the 3'-9" square and the smaller arch has the radius of the smaller rectangle.

Then to get my traditional teardrop trailer shape, I simply dragged the smaller arch left to the edge of the plywood.

Yay!  The final shape is a little boxy but still swoopy like the trailers we used for our examples.  And yes, swoopy is a technical term.  The next thing to do though was to see if this shape looked as good full scale as it did in the computer, so we made a cardboard template.

Its perfect!  Even our kitty Sophie seams to like it... I think... Next step will be a dry run with some scrap plywood we have then on to cutting out the real thing!

Finishing the floor

To finish the floor of the trailer I first had to add some insulation to the back two sections of the trailer. Instead of wedging the insulation at the bottom against the FRP, I rested it against the exposed edges of the metal trailer frame so that it could be glued to the underside of the plywood floor.


We decided that 1/2" thick birch veneer plywood for the floor because it was sturdy and the nicest looking wood they had at Lowes. The first step was to mark out the locations of the recesses onto the plywood floor and to cut them out. I made sure to save these pieces so that they can be used for the recess doors. I proceeded to glue down the plywood onto the wood frame to give it a little extra strength overall.


A snug fit but a good one! I installed a screw every foot along each side of the framing members, making sure to counter-sink each screw so that it was flush. Once this was done, the whole base of the trailer became much more rigid and gave us a sturdy foundation for the rest of the trailer.

When I cut out the doors, I made them slightly larger than the inside of the inside of the recesses. This resulted in a lip around the whole perimeter to support the doors when they are closed.


Before installing the doors, I gave everything a good sanding and made sure to smooth out all of the edges. We purchased some awesome recessed pulls from a local marine supply store and some simple hinges from Lowes. The recessed pulls needed to be embedded into the 1/2" plywood in order to lay flat. I was able to do this by utilizing a milling bit on my dremel. I think everything turned out rather nice!


Next step, side walls and framing. It's finally starting to come together!

Recessed storage

Since the trailer would be our home for the couple of months we are on the road, we wanted to try to include a much storage as possible. I thought a good way to carve out some space would be to recess a couple of cubbies into the trailer frame. Trying to design and determine how to install the recesses as deep as possible while maintaining enough room for insulation was the trickiest part of the build so far. The idea is that they are completely hidden, keeping the underside of the trailer flush.

I started by installing some 1/2" thick closed cell insulation in the base of the first two sections of the trailer. I did this by cutting the insulation to fit and then 'jamming' it in as carefully as possible. Any unintentional cuts or gouges to the insulation were covered with aluminum tape.


Unfortunately I didn't take many photos of the construction of the recess as I was attempting different things and learning as I went. I used 1x3 pine boards to create a box that would fit exactly within the floor frame members of the first two sections of the trailer. These boxes would sit on top of the insulation but needed to be ripped down around 1/2" to be flush with the top of the floor framing. After the box was made I attached small steel angles to the outside of the walls of the box to help support the 1/4" base that would lay on top of the insulation. This way they would provide some support but not be seen. To fit the 1/4" base, I simply traced the outline and used a jig saw to cut them out. After everything was fitted together, the boxes were screwed to the frame and voila! Storage! All in all they ended up being about 3" deep.


After removing the lights and wiring from the trailer, I proceeded to tape up any torn pieces of poly in the two open sections of the trailer. We cleaned it as best we could and sealed up any more cracks in the trailer that we might have missed before. This will be the last time we see the inside of the trailer before the floor is installed!

Floor framing

Because we both have smallish cars, we knew we would be using the trailer to transport materials. This meant before we began work on the base for the trailer, we would need to purchase all of the larger items - meaning everything that came in a 4x8 sheets. These items included 1/4" plywood sheathing for the roof, ceiling and interior walls, 1/2" plywood for the floor and 1/2" marine grade plywood for the exterior. But more on that later. Once the items were purchased and brought back to our assembly area, the base needed to begin.

The majority of the framework including the base will be built out of 1x2 pine which will be easy to work with as well as lightweight. We started out by building a rectangular framework of 1x2's on their side around the perimeter of the trailer which were glued and screwed together using pocket holes. The long sections of the frame were inset 1/2" so that the 1/2" plywood of the exterior walls could sit flush on the metal trailer and we would be able to screw straight into the wood frame.


I should mention that I was given a Kreg Jig for Christmas. This tool allows you to drill accurate pocket holes and create strong joints in wood. The kit comes with a special drill bit that fits into a standard power drill and is easy to use on any thickness of wood. So far we have only used it to make these frames, but it results in strong rigid connections and I would highly recommend it for any project!

After the exterior frame was completed I added additional wood framing on the flat at each of the of the interior cross members of the trailer as well as the front and rear cross members. These are what will be bolted through to secure the frame to the metal trailer base. They will also act as a support for the 1/2" plywood that will become the floor of the trailer.


With the wood frame complete, the next step was bolting it to the metal trailer with 9/16" bolts. First I pre-drilled each hole and created a recess for the bolt to sit in so that it would be flush with the wood frame. Since the trailer wasn't exactly level, we decided to use shims to make the wood frame level and make a better surface for the plywood floor to sit. I simply bolted directly though the shims then cut them flush after everything was done.


You may have noticed that the front two sections of the the trailer frame have additional 1x2's on the flat against the frame. This is for two recessed compartments that we are designing to give us some more storage!