Preparing the Interior

The interior of your trailer will probably need some work before you start turning it into a camper. In our case, the boards that made up the floor and walls contained formaldehyde. If you’re not familiar, it’s a substance that is commonly used to treat wood products, but it’s also used in morgues to prepare bodies. It can definitely make you sick if you are exposed to it for long periods of time. However, don’t let this discourage or scare you. If you’re dealing with a similar situation, there are steps you can take to make your camper shell safe before you start working on it.

Strip It Down

The wood panels in your cargo trailer can be painted with a zero-VOC (volatile organic compound) sealant and primer that will create a safe, livable space. Removing all of the panels will make this process easy, so that’s a good place to start. You may need a square or Torx bit for your drill in order to start taking out boards.

As you’re removing the flooring and walls, you may find some trim pieces that have to come off, too. Be careful as you’re removing them and save them, because you may want to use them in your design later. Keep all of the screws as you deconstruct the interior, because you can reuse them instead of buying more.

When you’re done taking out all of the interior pieces, you should have a basic metal frame, and you may notice some rust spots that you didn’t see when you were buying it. This is a good time to sand down and spray a protective enamel in places where rust is prevalent. It will save you headaches in the future. As a trailer owner, rust will always be your enemy.

Paint Time!

Use a latex-based sealant and primer on your boards for best results. We used Kilz brand zero-VOC sealant and primer. This not only sealed up and eliminated the formaldehyde risk, but also prepared our boards to be painted without any extra steps. We used rollers to make the project less time-consuming and it resulted in even and consistent coverage.

Be sure to get both sides of all boards to completely seal them and prepare them for re-installation. I recommend at least two coats to ensure complete coverage. Depending on the weather, it may take several days to complete this process as you’ll have to keep flipping the boards over.

Once you’re satisfied with your sealant work and it has completely dried, you’re ready to re-install the boards. However, there are a few things you can do beforehand to make your life a lot easier.


If you add insulation before you put the walls back, you will end up with a camper that retains its temperature for much longer and keeps out humidity. In our case, we put in a vapor barrier (but it can be as simple as a plastic dropcloth that painters use). This will be a good defense against unwanted moisture and other exterior elements. Then we installed insulation from a roll, cutting it to the right sizes to fit in the “bays” and taping it up for support. You will probably find that your cargo trailer has metal supports along the wall every 16-20 inches. If you leave those metal supports uncovered, it will be easier to re-attach the walls. As a side note, it will be much easier to insulate your floor once you have the boards back in, which we’ll cover in a later post.

Pro Safety Tip: Wear long sleeves, gloves, a mask, and proper eye protection (not pictured) when you’re handling fiberglass insulation.


If you know where you want your wiring to go, this is a great time to take care of that. Otherwise, you may find yourself removing a wall again or needing to fish wire through the back of the wall. In general, we ran wiring underneath the camper, reducing the need for wiring in the walls themselves. However, we did have to plan for solar wiring, antenna wiring, and overhead lighting wiring, as those all involved the roof or ceiling. You’ll be a happier camper if you have this planned out early and get it installed before you re-attach the walls.

Put Walls & Floor Back!

Now that you have sealed up your wooden boards, you’re ready to put them back in your camper. Best done with two people, this process is the exact reverse of removing them, aside from the fact that you will have to re-align said boards with their mounting holes and hold them steady as you install them. We also added a little bit of construction adhesive underneath the floorboards to ensure they would stay put. Depending on the thickness of the insulation you selected, it may be slightly difficult to reinstall these, and a helper could push the boards up against the wall or floor as you re-attach them with the fasteners you saved during step #1.


Enjoy Your First Milestone

Believe it or not, this is one of the more labor-intensive steps to turning your trailer into a full-blown tiny camper. Celebrate your formaldehyde-free victory and get ready to install your interior finishings!

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