teardrop trailer, design, sketch

How to Build a Teardrop Trailer

Teardrop trailers have gained in popularity in recent years. One of the oldest travel trailer designs, it’s resurgence has come about due to its small size, light weight and ease of towing. With many people driving smaller cars today, they can’t pull a full-sized travel trailer. But a teardrop trailer can be pulled by today’s smaller cars, with their smaller engines.

All teardrop trailers share similar design characteristics, other than their signature shape. These include some inside storage, the bed, which takes up the majority of the space, and a rear hatch (think trunk lid), opening up to reveal the kitchen. Teardrop trailers are typically low, to make them more aerodynamic. Their short door means that they just about need to be crawled into. Even so, they provide the essentials for camping, as long as you have a bathroom nearby.

teardrop trailer, design, sketch
Teardrop trailer design

Within these basic constraints, the there is still a lot which can be done to customize a teardrop trailer design to your particular wants our needs. Storage spaces can be modified, the kitchen can be customized and even the profile of the teardrop can be modified slightly, allowing the ends to bubble out past the end of the trailer frame.

Typically, these trailers are eight feet long and the side walls are four feet high. This allows the sides to be cut out of a single sheet of plywood, simplifying construction and reducing cost. However, if you bubble the ends out past the ends of your trailer frame, you may not be able to make your sides out of a single sheet of plywood.

One major consideration as you are designing and building your teardrop trailer is keeping the weight down. It is very easy to end up with a heavy trailer, that your car will have trouble pulling. If the trailer is difficult for you to move around by hand, without having a wheel on the hitch, it might be getting a bit heavy for your car.

Start with the Structure

To start with, you need a trailer frame to build the teardrop trailer onto. While it is not all that hard to build a trailer frame, you can buy simple flatbed trailers from the major home improvement centers and some of the tool supply houses. A 4 foot by 8 foot trailer is fairly standard as a base for a teardrop trailer, but if you can find a 5 foot by 8 foot one, you can have considerably more room inside your trailer. These are also available with aluminum frames, which lower the trailer’s weight.

If you decide to make your own trailer, you are better off using steel angle, rather than square steel tubing. While the square steel tubing would make for a stronger frame, it would be overkill, adding a considerable amount of weight for no real benefit.

The teardrop trailer will have a tendency to be a bit heavy to the back, due to the kitchen being located there. To compensate for this, move the axles and wheels 6 to 12 inches towards the rear. If this isn’t enough to keep the trailer from pulling up on the hitch, add weight in the front, such as by mounting a water tank to the A-frame of the trailer.

The floor of the frame should be covered with ¾” plywood. It is best to use pressure treated plywood for this, as otherwise there is a great chance of it decomposing from water splashing up onto the bottom side while you are driving. Even undercoating won’t do as good a job to protect the floorboards, as pressure-treated plywood does.

If you do use pressure-treated plywood and then want to apply undercoating or paint later, you must give the plywood six months to dry out, before applying it. As purchased at the lumberyard, the resin in the pressure-treated plywood is still wet, so paint won’t stick well.

Building the Walls

There are two basic ways of building walls for a teardrop trailer:

  • Making a laminated bow, with 2”x 2” framing
  • Cutting the framework out of plywood
    • Plywood Wall

      The laminated bow is actually stronger and lighter than the plywood frame, especially if you pin the joints, but it is much harder to make. On the other hand, you can cut the side frames out of plywood in a matter of a couple hours. The key, in this case, is to create a lot of empty space, so as to lower the overall weight of the structure. While one layer of plywood will work, you can add more insulation, if you use two layers.

      Another possibility is to make a composite wall structure, using thin plywood for the outer and inner skins, with a Styrofoam center core for insulation. Some motorhome and travel trailer walls are made in this way. If you do choose such a construction, you will need to be sure to have a wood core in the areas where things need to attach:

      • Bottom edge
      • Roof edge
      • Where the wall partition attaches
      • Around the door
      • Around windows
      teardrop trailer, walls, sketch
      Teardrop trailer walls

      As you can see in the diagram above, the majority of the plywood has been cut out, providing empty space to lower the weight. This area will be filled with insulation. Wider areas have been left where the interior partition has to attach and for support of the door.

      Laminate Wall

      If you decide to use a curved laminate, you’ll need to start by ripping a whole bunch of 1-1/2” strips of thin plywood. If you can find it, you want to use 1/8” thick; if not, go with the thinnest you can find. As with any curved laminated construction, you have to make a mold for forming the curve around. This can be a temporary setup, as you only need to use it for two parts. But it has to stay the same for both and not move when you remove the first one. Covering the mold with wax or waxed paper will keep the glue from sticking the workpieces in place.

      To make the laminate, first soak the strips of plywood in water, to make them pliable. Then starting from the inside, layer the strips of plywood onto your mold, coating each strip with glue, so that it will stick to its neighbors. You will probably need to clamp each piece, as it is put in place, then remove the clamps, one at a time, to place the next one.

      Continue adding pieces, staggering the seams, until the desired thickness (1-1/2”) is reached. Check to see that they are all flush and there are no gaps, then clamp everything thoroughly, leaving it to dry.

      Once the curved pieces are finished, the rest of the wall is built out of 2”x 2” dimensional lumber. To make the joints stronger, I would recommend doweling them to attach them together.

      Finishing the Outside

      The outside of the wall can either be a thin layer of plywood or aluminum, depending on your preference. Both styles are popular, with the plywood exteriors often including contrasting wood strips to create the same sort of effect as a “woodie” if you remember what those are. Wood sides and roofs need several heavy coats of urethane varnish to protect them from moisture and rotting.

      Framing the Roof

      The roof of the teardrop trailer basically extends from floor level at the front of the trailer to floor level at the back of the trailer. It is unbroken, with the exception of the kitchen hatch. However, the only real difference there, is going to be the spacing between the roof supports.

      The major structure of the trailer is the walls that we just discussed. So all the roof structure has to do is support the roof itself. It also provides some rigidity to the walls, to keep them from collapsing, but this is secondary.

      The roof bows can be nothing more than 2”x 2” dimensional lumber, cut and fitted between the walls. They can be nailed or screwed, but for added strength and rigidity, I would dowel through the sides to attach them. You’ll need to cut and flute your own dowels for this, as standard commercial dowels are only 2” long and you need these to be at least 3” long.

      To install the roof bows, first lay out their position and cut all the bows. Then nail them in place, with finishing nails, so that the top of the bows is flush with the top of the walls. This will allow the roof to overlap the top edges of the walls, providing beater weather sealing. You need to make sure that your finish nails are not in the way of where you need to install the dowels. With all the bows in place, you can drill ½” holes for the dowels and glue them in place.

      For added strength, you may want to support the roof bows with a 1” steel or aluminum angle, on the inside. However, this require bending that angle to fit, which will be a great challenge. It will also make it harder to install your inside wall and roof covering. If you want this added strength, you may want to consider installing angle brackets to the sides of the roof bows instead, keeping them to the sides, where they will be hidden within the confines of the insulation.

      Kitchen Hatch

      You should build the frame for your kitchen hatch at the same time you are installing the roof bows. The last bow above the hatch will be what you attach the hinges too, so you’ll want to make this roof bow extra strong. The first one below the hatch is going to have to be strong as well, for latching.

      This hatch will be considerably trickier to build than the roof bows. It’s not enough to just go with a simple ladder design. That will flex and eventually break. Rather, you need a minimum of four longitudinal runners, curved to match the roof. These can either be laminated pieces, just like we discussed for making the top edge of the side walls, or they can be cut out of plywood.

      A few supports will be needed between these four curved longitudinal pieces, but the major horizontal support will be at the top and bottom of the hatch. Be sure to reinforce the corners well, so as to ensure that it doesn’t flex and break.

      The hatch needs to be sealed, so as to prevent water from coming in while driving down the road. This can be done by attaching aluminum angle, around the edges of the hatch, in a way so that it will overlap the roof. On the leading edge, you will want to attach an additional piece of angle, over the roof skin, to catch and divert water that is being driven down the length of the roof, so that it doesn’t go under the hatch’s lip. Rubber seals under the angle and good tight latches will finish off the sealing of the hatch.

      Another option, is to install what is known as a hurricane hinge on the leading edge of your kitchen hatch. These are hard to find, but they are a special type of hinge, which presents a water barrier to water that is flowing over the skin of the trailer. It is worth the effort to find one if these if you can.

      Insulating, Wiring and Skinning

      At this point, your side walls are skinned over, but the roof is not. You need to skin the roof on the inside first, so that you can install the insulation. Then the outer skin can be installed. If you install the outer skin first, you’ll have quite a problem installing the insulation.

      However, before skinning anything, you need to run any wiring for lighting or other devices. Your wiring should include:

      • Interior lights for sleeping quarters and kitchen
      • Exterior trailer lights
      • Porch light
      • USB charger ports
      • Speaker stands wiring
      • Water pump for kitchen sink (if needed)
      • Battery (to power everything)
      • Battery charger

      Once the wiring is in place, you’re ready to put the insulation in. You can either use fiberglass batts or Styrofoam sheets for this. The Styrofoam is easier to work with, but you will have to cut channels into it for your wiring. Batts are better in this regard, as they compress to make allowances for wiring and other things in their way.

      Next, you’ll want to skin over the inside walls and ceiling. Be careful at this stage, because it is easy to trap yourself into a position where you can’t get pieces inside the trailer. They all have to slip through the roof bows, so that means the ceiling is actually the last piece of the interior skin to install. Basically the order to follow is:

      • Side walls
      • Partition (both sides)
      • Ceiling

      Most people skin over the inside of their teardrop trailer with ¼” paneling or plywood, depending on their personal preferences. This is flexible enough, that you should be able to make it curve to match the inside of your ceiling, without problem.

      Once the inside of the trailer is skinned, you can install the roof insulation and then skin over the outside. The corner where the roof meets the walls should be capped with a thin aluminum cap. This will be a bit tricky, as the aluminum will have to curve, as well as fold over the corner. One way of accomplishing this is to take an angle and slit the walls side, allowing the edges where it is cut to overlap each other. Just make sure they overlap from front to back, to keep water from seeping under.

      Doing it this way, you should apply some sort of sealer to the cut edges. You will also need to ensure that you attach the cap well, so that there are no sections which do not have hardware holding them in place.

      Install the Cabinets

      Cabinets, especially the kitchen cabinets, are where you see people really allowing their imaginations to kick in on teardrop trailers. You will want to design your storage space in such a way as to accommodate the things that you will bring with you as you travel. Some of the things you may want to consider:

      • You’ll need space for the clothing that you are taking with you, as well as to store dirty clothing that you have already worn.
      • Many people like to take along a laptop computer, tablet or small television, so they can watch television or a movie. You might want a cubbyhole set into your cabinets, which allows you to lay back and see the screen from your bed.
      • Don’t forget about space to store personal toiletries.
      • You’ll also want space to store all those small camping items, which are so important, like flashlights and insect repellent. Don’t forget those.

      Underbed Storage

      You can easily add underbed storage to your teardrop trailer by making a framework out of 1”x 4”s or 1”x 6”s, dividing the floor space into areas that are roughly two foot square. This is a convent size for storage, without having to have a door that is so large, as to be unwieldy.

      Most people use a futon-type mattress in a teardrop trailer. So take into consideration how your futon will fold, when laying out any underbed storage. In most cases, you’ll want to hinge at the centerline of the trailer, with the opening towards the outside. This will allow you to flip up one half of the futon to access the storage on that side and then flip it the other way to access the rest of the storage.

      Kitchen

      I’m not going to get into a big discussion about the design of the kitchen space, as everyone has their own ideas about an ideal kitchen for camping. Rather, I will merely provide a few pointers that you won’t want to forget.

      • Make sure that you have adequate space for your ice chest. I’ve seen many a person make a space to put their ice chest and not leave enough space for the handles. Oops!
      • The main kitchen shelf, shown in the first diagram, will be your countertop. I would add a couple of shelves above this, including a small one just about at the roofline, for spices, matches, tea bags and other small items that you want to have easy to find.
      • Shelves should have a railing, to keep items from falling while driving.
      • If you have any full-width shelves, partition them to help keep things in place.
      • Install a paper towel holder somewhere, like on the inside of the kitchen hatch.
      • Don’t forget gas struts or prop rods for the kitchen hatch, including somewhere for them to store while you are moving.
      • If you are going to use a gas stove (camping stove), then make a slide out or flip up stand for it, so that it doesn’t take up all your counter space.
      • Be sure to provide yourself with someplace to hang a trash bag.

      Finishing the Trailer

      Your trailer is just about finished. All that’s needed are some finishing touches. The door and windows can be bought commercially and installed. I would recommend this, rather than trying to build your own, so that you don’t have to worry about them sealing properly. Building a trailer door that will seal is tricky, even worse, when you want a screen door (a necessity) as well.

      Trailer light kits and fenders for your wheels are available commercially and easy to install. Lights often come in a kit, along with the wiring. This wiring can be done under the trailer, rather than through the walls.

      With the trailer built, you can apply any stain, varnish or paint that you desire, to customize your trailer, perhaps making it match your car. Be sure to seal everything thoroughly, filling any seams or holes with silicone caulk to protect them from water getting in.

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