How To Insulate A Camper Shell


There are many reasons to insulate a camper shell. You may be wanting to take a road trip across the country with your best friend in tow while enjoying the freedom of the open road. Regardless of why you want to get outside with your camper, it’s important to have proper insulation in order to stay just the right temperature.

How do you insulate a camper shell? Here are the seven steps to insulating a camper shell:

  1. Collect Installation Tools and Materials
  2. Measure your Camper Shell
  3. Clean and Prep Your Camper Shell
  4. Purchase Your Installation Materials
  5. Add Your Bracing
  6. Install Insulation
  7. Finishing Touches

This is a lot of steps, but with proper planning, insulating your camper shell is actually really easy to do. Let’s break down the steps for you.

Insulating Your Camper Shell In Seven Easy Steps

Step One: Collect Installation Tools and Materials

For this project, you will also need to make sure you have all the tools you will need to do the job correctly the first time. You have already looked at your insulation choices, now here are the other tools and materials you may need.

  • A Saw (Circular or Table)
  • 25ft Tape measure
  • ½ in. wide aluminum strips (refer to your measurements)
  • A long straight edge, for drawing lines
  • A felt tip marker
  • Utility knife
  • Plywood/Soundboard
  • Some 2×4’s (refer to your measurements)
  • Some 1×4’s (refer to your measurements)
  • Great Stuff Foam
  • Liquid Nails Construction Adhesive
  • Screws
  • A Power Drill

Step Two: Measuring Your Camper

Take measurements of your camper to figure out how much material and insulation you will need. You will need to measure the following:

  • Ceiling
  • Walls
  • Windows 

You also need to measure for bracing. I recommend using wood bracing to frame where you’re going to put your insulation in order to help secure it in place. You should space the bracing at least 16” apart, as that is the standard width of wall insulation for homes. You may also want to put aluminum bracing over the top as well, for added support. 

When you are measuring for baracing you want to measure from one end, I would measure starting from the tailgate, so that your spacing is even on both sides. Your final brace may be off but that is okay, just make sure it’s even on both sides.

I recommend insulating around your windows, not over them. Instead, consider insulating some soundboard cut to fit over your windows. You can use it as needed, while retaining the benefits of having windows.

If you need help with taking measurements, I found this helpful cheatsheet from CoverCraft you can use as a guide.

Step Three: Cleaning and Prepping Your Camper Shell

If your camper shell has been sitting for a while, you should look it over, looking for any rusted spots that may need to be cleaned and repaired. You can grind away small patches of rust using a wire wheel for a power drill or wire disk and angle grinder. Either patch wield any big holes or use JB weld for smaller ones. 

If your shell is fiberglass, a fiberglass repair kit can be used to repair any holes and cracks that may have developed over time.

Spray foam, like Great Stuff Foam, is great for sealing small cavities that are difficult to fill with other forms of insulation, during the layering process. This is expanding foam, and a little goes a long way; so use it sparingly. I would put this around any windows in your camper shell for added weather seal. You may need to trim the foam with a utility knife once it has cured completely. 

Also, check the condition of all the weather stripping on the camper shell, including around any windows the shell may have. If any is missing or damaged, replace it before starting the insulation process. Damaged or missing weatherstripping creates air gaps, allowing heat to enter or escape.

Step Four: Purchasing Your Project Materials

Once you have cleaned up your shell and repaired it, decide what insulation you are going to use. I recommend a combination of materials for the best R-value. I will talk more about different types of insulation further on. Make sure you buy the wood you need for your bracing. For a camper shell I would use 1×4 for bracing. You can also use 2×4 if you’re not concerned about space conservation.

No matter what insulation you choose, apply a layer of Reflectix and sticking it in place with a spray adhesive. You can find spray adhesive in any hardware store, just make sure it works for either metal or fiberglass depending on your shell. You will be putting materials over it, so it just needs to stay in place long enough to apply your next layer. 

Step Five: Adding Your Bracing

Applying the layers is pretty straight forward, you started the process already by applying a layer of Reflectix moisture barrier. Now, build the wood bracing over it and secure it with a construction adhesive. Putting the moisture barrier down before the wood also protects the wood. You can use treated wood too if you are worried about any rotting. 

Use an adhesive, like liquid nails, to attach the wood bracing to your camper shell. Here is a video example demonstrating how to apply the adhesive. In the video, they start out using a spray adhesive before switching to construction adhesive. You will notice in their video, they don’t frame anything. They didn’t need to, in this case, because the curvature of the van made its own frame.

Step Six: Installing Insulation

Once your backing is in place, cut your insulation to fit, and put it in place. Here is another example of insulation methods. In this video, once he finishes the insulation process, he covers it with a piece of soundboard.

For a canvas camper shell, you can build a shell out of rigid styrofoam and duct tape. Then slide it into place when you are ready to use it for extra insulation. I would make sure you build it with the radiant side facing outward to reflect heat. The radiant side has a metallic film on it. Here is a quick video to give you an idea of how to go about insulating it.

Step Seven: Finishing Touches

After applying the insulation. check for any little spots you may have overlooked and seal them up. Additionally, seal all your seams with duct tape or a construction grade joint tape; it’s up to you. Just make sure you are sealing up any small air gaps. You can also add extra support over the insulation using metal strips if you choose.  

Again,you can also use Great Stuff foam, to fill in any areas you didn’t get with insulation. Small cavities of air and reduce your insulation value. You can also use a less permanent method and fill storage holes with clothing, or your natural insulation as needed.

Now that you know the basic steps, here are some things to consider before starting your project.

Why do you want to insulate your camper shell?

The reason behind why you are insulating the camper shell is important when starting your project. If you are merely using it for weekend camping trips in the summer, you may not need to insulate it as heavily as you would if you were living out of the vehicle year-round. 

What type of camper shell do you have?

There are many things to consider when choosing a camper shell. For example, a metal surface may need a stronger formula spray adhesive than a fiberglass shell would. You may also have to rough up the surface of a metal shell inorder for the adhesive to have a proper porous surface to adhere to.  The three common types of camper shells are:

  • Fiberglass
  • Metal
  • Canvas

Fiberglass

Fiberglass camper shells are the most popular type of shell on the market today. They are customizable, and easy to produce, which makes them appealing to anyone looking to rough it for a weekend, or making the leap to downsize and live off the grid.

Fiberglass is non-conductive, it is a better insulator than metal, and it’s stronger than canvas should the weather turn rough. Making it better suited for any wilderness environments you might be exploring. 

Metal

Metal camper shells are also a good choice. Many newer models come with a nice protective coating to keep the metal from rusting. However, metal heats up in sunlight, which can be a problem in hot climates. I recommend making sure it has windows that can be opened, in order to vent heat and circulate air. This goes for any style shell you use. If your shell doesn’t have windows, you can install some of yourself.

Canvas

Canvas shells can be insulated as well but are not recommended for heavy-duty use. They are light, making them more maneuverable than other options: perfect for day trips to the beach or a quick trip to the lake. The insulation for this type of shell would have to be removable, lightweight, and would have a low insulation rating. It is a good option for recreational use and can be used for camping overnight in mild climates. 

Choosing Insulation

Insulation rating is important when planning your project. The higher the R-value, the better insulation you have. Knowing the purpose of your project is important in determining how heavily you insulate. Again, if it’s meant to be for occasional recreation, you can go with a lower rating than you would if you were converting a vehicle to live in, year-round.

What is R-value?

R-value, or R-rating, is based on an insulation material’s ability to resist heat flow. It is allowing the air inside the space to stay at a consistent temperature by retaining either warm or cool air.

Insulation Choices

Here are four types of insulation to consider for your project. You may want to use a combination of materials, for better insulation rating.

  1. Styrofoam
  2. Fiberglass Insulation
  3. Mineral Wool Insulation 
  4. Natural Fiber Insulation
  5. Reflectix
  6. Spray Foam

Styrofoam

While there are a variety of brands to choose from rigid styrofoam, here are the top two brands you will likely find at your local home improvement store: R-Tech and Foamular.

R-Tech

R-tech has a low R-value and a higher moisture absorption rate. However, as a general rule, rigid styrofoam has low moisture absorption to begin with. Using a moisture barrier will also decrease the absorption rate and is recommended for this project anyway. Condensation will be an issue, as none of these products is 100% moisture-proof.

You can find R-Tech in a variety of thicknesses, but for the purpose of this article, I will be listing the R-value up to 2” thickness.

Here are the commonly used thicknesses for lining a camper shell and their R-value. (It is important to note their R-ratings are based on long term product use.)

  • ½ in. R-value 4.93
  • ¾ in. R-value 5.89
  • 1 in. R-value 6.85
  • 1 ¼ in. R-value 7.81
  • 1 ½ in. R-value 8.78
  • 1 ¾ in. R-value 9.74
  • 2 in. R-value 10.70

Foamular

All styrofoam insulation panels use similar, closed-cell technology. However, Foamular focuses on reducing moisture absorption and increasing initial R-values. Here is a full list of the products they offer.

Foamular 250 XPS insulation foam panels are the most practical choice for a camper, as you only need basic insulation. If you want more R-value, you can also layer materials, which I will talk about more about in a moment.

Foamuler has two ratings listed on their specifications sheet, one is initial R-value, and the other is the long term usage R-value. I am going to use their long term rating since I feel it is the most relevant for this article. You can find the complete specifications here.  

  • 1 in. R-value 5.0
  • 1 ½ in. R-value 7.8
  • 2 in. R-value 10.6

Fiberglass Insulation

Fiberglass Insulation is another great choice. Keep in mind fiberglass is a skin irritant. I would definitely make sure to put some sort of cover over it after placing it down, to prevent unwanted contact. Again, you can find fiberglass insulation at your local home improvement store. I would use a rating between R-11 and R-15.

  • EcoTouch  
  • JM ComfortTherm

EcoTouch

The EcoTouch line has an R-value range of 11-49. It comes in thicknesses ranging from 3.5” to 14”. Stick to something with a lower R-value range if insulating fiberglass. 3.5” depth is a lot of compartment space to give up in an already small area, especially since you will be placing something over the top of it. Using fiberglass would probably be better suited for larger vehicles, such as a bus or a van.

JM ComfortTherm

ComfortTherm only comes in R-13 rating, which makes it an easy choice for anyone who chooses to insulate with fiberglass. It is good for both temperature control and sound deadening. It is also available in pre-cut batts.

Mineral Wool Insulation

Mineral Wool Insulation is technically in the same group as fiberglass. The fibers are not made from glass, though. If I were to go the fiberglass route, I would consider this option over the traditional formula. 

Rockwool Comfort Batt

Rockwool Comfort Batt is considered a type of fiberglass insulation. Instead of using glass fibers, it is actually made from ground stone that is spun and layered into semi-rigid insulation with a unique edge designed to compress and seal. It is also fire resistant. Learn more here.

Natural Fiber Insulation 

There are also a few options for those who are eco conscious and wish to use natural and sustainable materials for their insulation project. 

  1. Wool Insulation
  2. Denim Insulation

Denim Insulation

From a sustainable standpoint, if you are going with a fibrous insulation option. It is made from 100% natural fibers, denim, and cotton, which means no itching skin.

UltraTouch

UltraTouch provides effective sound absorption, and maximum and thermal performance. It’s also naturally more resistant to mold and mildew. Visit Banded Logic for more details. Here is a quick list of UltraTouch R-ratings per thickness, for more details click here.

  • 2 in R-value 8
  • 3 ½ in. R-value13
  • 5 ½ in. R-value19 (available in R-21 also)
  • 8 in. R-value 30

Wool

Another great option as a sustainable insulation is wool. lt’s not only great at keeping sheep warm, it can do the same for you and your family. It is a great insulator, and naturally able to absorb, trap, and release moisture at a higher rate than other man made materials. It also has a higher compression recovery rate, than man made insulation.

It is animal conscious, as sheeps wool becomes extremely heavy and pulls on the sheeps skin over time, which can cause many health issues. Since it has to be sheared regularly for the health and safety of the animal anyway, why not use the byproduct to insult a living space? Find out more information here.

NatuWool

NatuWool is a company based out of the UK  that specialises in natural insulation materials. Their product’s natural ability to manage internal moisture levels, makes it resistant to mold and mildew it the most health conscious option out there, because of its natural resistance to mold and mildew. You can find a complete list of Black Mountain Sheep products here.

I will list the measurements in inches for this article. However, if you order insulation from this company keep in mind the UK is on the metric system. You will have to adjust your measurements accordingly. They also measure the R-Value as Thermal Resistance. Here is more detailed information on their wool insulation.

  • Approx. 2 in. R-value 1.28
  • Approx. 3 in. R-value 1.92
  • Approx. 4 in. R-value 2.56
  • Approx. 6 in. R-value 3.85
  • Approx. 8 in. R-Value 5.13
  • Approx. 10 in. R-value 6.41

Reflectix

Reflectix is mainly used as a radiant and moisture barrier. As insulation, it has a very low rating of R-1. Even with such a low rating, I recommend lining your shell with it for added protection, before adding any other insulation. Find more information here.

Spray Foam

You can use spray foam as an insulation method as well. However, it tends to be messay, and you may want to make sure you apply plywood over it immediately after filling the wood bracing, screwing it firmly in place so it will hold as the foam expands. 

Installing Insulation

Installing insulation is mostly cutting the insulation and putting it in place. However, depending on your type of insulation, there are slight differences when installing it. 

Fiberglass

If you are using fiberglass insulation, make sure to put the fibrous side facing inward. You also want to make sure you have your arms and face covered to protect your skin. 

Rigid Styrofoam 

If you are using rigid styrofoam, you may also need to score the back of the board in order to mold it to the curvature of the shell. You can also cut it into smaller pieces to fit it into place. You can use the same spray adhesive you used to apply the Reflectix or use construction adhesive to secure the foam in place. 

Layering Methods

Layering your insulation is a good way to raise your R-value. It can also help with moisture control. Here is a great video that shows a van conversion start to finish. In it, you can see how they layer their materials. 

Creating Air Pockets

You can create little air gaps between layers of insulation to trap air, using the layering method. This raises your R-value and will keep you warmer on cold nights. 

Now You’re All Ready to Insulate Your Camper

While the process of insulating a camper may seem difficult, it really is quite simple. The difficulty level of the process depends on how insulated you want your camper to be. The majority of your time is spent planning your attack method. 

I suggest going on YouTube during your planning stage and watching videos on converting vans or busses into living spaces. They use a lot of different techniques in a single conversion, so you can cherry-pick ideas from other conversion projects and apply them to yours. Having visual references works much better when trying to learn a new skill. 

Thanks for reading, have fun building your new project!


If you’re thinking of different ways to accessorize your truck or make it more functional, consider checking out my recommended accessories page. I spent a good amount of time picking out mods that can be useful for most pickup trucks.

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