Best Insulation for Cargo Trailer Conversion

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The most important part of converting your trailer to a camper is choosing the right insulation. How much insulation you need depends on your climate, the amount of insulation you have currently, and your plans for your future. 

In this article, we will discuss the various types of insulation you can use for your trailer and how much insulation you need for different climates. We will also walk you step by step on how to insulate your trailer. Ready to get started? Let’s go!

The Different Types of Insulation for Cargo Trailers

Most trailers come with a ventilating system, but what type of insulation should you use? What type of cover will give you the best protection to the vents? It’s simple. The three most common types of ventilating systems are:

Ventilation: A ventilating system is also a must-have for your trailer.

Concealed Air Entry: A blanket or waterproof cover to the door provides a warm and humid environment to the interior. 

Closed Off Air Entry: Concealed door systems are ideal for caravans and gypsy wagons and are usually installed to the back of the trailer. 

How To Insulate a Cargo Trailer?

Niu3jfv best insulation for cargo trailer conversion
Source: Tacoma World

According to the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), up to 3 inches of insulation should be used in the cargo area of your camper, which includes both the trailer and the bunk area. 

Also Read: How to De-winterize a Travel Trailer?

Keep in mind that the roof, walls, sides, and floor of your trailer need to be insulated at least as much as 3 inches. For example, the bed of a 4×8 trailer will be insulated at least 3 inches. 

This should go without saying, but you should be sure to cover your entire trailer roof (the largest surface) with a thick, waterproof coating. 

Which Areas in Your Cargo Trailer Should Be Insulated?

Insulation choices for a trailer are highly personal and all depend on what climate you are in, the amount of storage you have, where you are going, and whether you want to put the trailer inside or outside your house.

The choices you make will depend on the type of trailer you have, and you will also have to consider the position of the door, the sleeping quarters, and where you want to park the trailer when you are not using it. 

Carbon-fiber panels can be added to the ceilings and the walls of your trailer, or you can install high-density polyethylene (HDPE) ceiling and wall insulation under the trailer. Your choice of insulation will greatly depend on how much storage you have in your trailer, how well you need to keep the trailer insulated, and the desired temperature you wish the trailer to have.

Materials Needed To Insulate a Cargo Trailer?

Tools and Materials Needed:

Vitoki heavy duty hand sewing needles kit for home upholstery carpet leather canvas repair by vitoki, pack of 7

Carpet Needle Guage

(12-pack) 16 in. X 16 in. Commercial grade all-purpose microfiber highly absorbent, lint-free, streak-free cleaning towels - the rag company (grey)

Microfiber Towel

Superior 700 gsm long staple 100% combed cotton, durable, plush and absorbent 6-piece single ply towel set, green essence

Single Piece Towel

Small fish ‌organic cotton‌ ‌produce‌ ‌bags,‌ 5 pcs. ‌large,‌ organic, and ‌reusable‌ ‌canvas‌ ‌muslin‌ ‌‌‌drawstring‌ ‌‌sack‌ ‌for‌ organizing, ‌shopping,‌ storage,‌ ‌grocery,‌ dust cover, and ‌gift

Cotton Sack

Adhesive foam tape weather strip for doors sticky foam strip insulation soundproofing tape single sided closed cell foam tape 1/4 inch thick x 1 inch wide,2 rolls

1-2 rolls Insulation Tape

Champion sports vinyl tape, 1” wide x 60 yards long, red - durable floor marking tape for social distancing, school, gyms, restaurants - tough floor tape for heavy foot traffic and equipment

Vinyl Tape

Fowong open cell foam seal tape 2 rolls, 1" w x 1" t x 13' l, air conditioner seal low density door insulation strip high resilience flame resistance, 2 x 6. 5 ft
Insulation Strips

Sound deadening mat 50 mil 52 sqft | sound deadener mat | car sound dampening material | sound dampener | sound deadening material sound insulation | car sound deadening bulk kit trunk hood door mats

Insulation Sheets Materials

Mat board center, pack of 10 foam boards, 11x14 inch (many sizes available) 1/8" thick, white foam boards (acid-free)

Foam Board

Double sided tape heavy duty 1. 97 inch x 32. 8 ft mounting tapes super strong foam tape moulding automotive adhesive two side heat resistant

Heavy-Duty Foam Resistant Tape

100 pack eva foam sheets, 5. 5 x 8. 5 inch, assorted colors (20 colors), 2mm thick, by better office products, for arts and crafts, 100 sheets

Foam Sheets

Weewooday 2 pieces pet bathing tool set include livestock foamer and dog rubber comb, spray livestock foamer wash foam sprayer, pet bath brush rubber dog comb for pets showering (green)

Foam Sprayer Tools

Square trimmer blade by bevel - beard trimmer for men, precise lineups, trimming and shaving for face, head, and body, for all hair types, works with bevel trimmer, silver

Bevel Blade

Dremel lite 7760 n/10 4v li-ion cordless rotary tool variable speed multi-purpose rotary tool kit, usb charging, easy accessory changes - perfect for light-duty diy & crafting

Grinder or Dremel Tool

Black+decker dustbuster handheld vacuum, cordless, 16v (chv1410l) , 21oz , blue

Heavy-Duty Squeegee or Vacuum Cleaner 

Scissors, ibayam 8" multipurpose scissors bulk 3-pack, ultra sharp blade shears, comfort-grip handles, sturdy sharp scissors for office home school sewing fabric craft supplies, right/left handed


Aluf plastics plastic sheeting - 10' x 100', 6 mil heavy duty gauge - clear vapor and moisture barrier sheet tarp/drop cloth for painting, furniture covers, carpet cover, floor, paint, painters

Plastic Sheeting 

Plastic sheeting is an excellent material to use for insulating your cargo trailer. It will help to keep your trailer at a comfortable temperature even during the cold months of winter. 

Plastic sheeting is basically a reflective material and will help you stay at a comfortable temperature even at night.

Steps To Insulate a Cargo Trailer?

Construction Details: 

Before starting any insulation job you need to understand how much insulation you will need. We will say it again: to make sure you get the right insulation, you need to know how much insulation your trailer has. 

Insulation in pounds: 3/4 of a sheet of R-38 You can find different types of insulation in different trailer models. Each trailer has different regulations and the specifications might vary. If you are looking for the best R-38 you can use for cargo trailers we recommend using the R-38 1-inch. 

1. Consider Replacing Your Old Windows

If you’ve got small windows, replace them with low-E glass. This type of glass blocks 99.9% of infrared radiation, which means your cabin stays much cooler in summer. 

You can also use this type of window in a separate enclosure for privacy. Insulation is the key. 

The most important and the most crucial part of insulating your trailer is insulation. You need the right insulation because the incorrect insulation will lead to a very hot cabin or a very cold trailer in winter. 

Also Read: How to Get Rid of Your Old Motorhome?

For insulating your trailer, insulation from the outside will work best. Depending on your climate, use either mineral fiber or cork to insulate your trailer. 

For insulated interiors, insulating coverings are very effective and are affordable.

2. Reseal Doors

Consider replacing the existing rubber seal in your doors or using a wax seal if your trailer does not have one. Wax seals provide better insulation and the interior can be kept cool even when your truck is parked at 80 degrees. Just make sure to wash the wax seal with soap and water or use a can of WD-40 to keep it clean.

3. Cover Your Vents

Vents are one of the most important things you need to insulate. These are openings into your trailer that allow moisture and carbon monoxide to escape. 

Vents have to be sealed in every type of trailer that you plan to live in. Even if you didn’t purchase a double-walled trailer, you can insulate them with foam peanuts. 

The problem is that you don’t always have the space to insulate them properly. So we recommend a three-stage approach.

The first step is to cover your vents. Next, we recommend insulating your floor. And finally, we recommend sealing your ductwork.

4. Skirt the Trailer

If you are not planning to convert your camper to an RV, you will probably want to skirt the underside of your trailer. You do this by cutting off the roof and removing all metal and plastic, except for one metal shield which will cover your exhaust. 

This will allow you to maintain your carbon footprint while still providing the necessary airflow. 

An aftermarket skirt is a piece of 2″ or 3″ galvanized steel attached to a tubular frame. Since this type of skirt has more flexibility than a rigid steel structure you can install it at any point along the length of your trailer.

5. Reinsulate the Walls

Reinsulating the walls ensures that when you take off the carpet it doesn’t expose the walls to the elements. When you install vinyl flooring, you don’t want any gaps between the flooring and the walls of the trailer. 

It’s actually recommended to install a full 10-foot vinyl barrier between the flooring and the walls. This will ensure that if any part of the RV gets wet, it won’t touch the walls. 

6. Reinforce the Sealant 

It is recommended that you cover all the joints with thin plastic sheeting to prevent moisture. 

To prevent moisture from coming in, you need to fill the leak points with the appropriate amount of caulk or double-sided tape to seal the joints. To avoid damaging the sealant, use a scraper to remove any excess from the joints.


We hope you enjoyed our article on the best insulation for cargo trailer conversion, and that you’ll take the information to heart. As you now see, it really isn’t difficult to insulate your trailer. With a little time and patience, you’ll have a comfortable trailer that will keep you as cool or warm as you need it to be. 

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