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How To Install Better Insulation In Campers And RVs

Improve RV Insulation

Insulating your RV better

How To Install Better Insulation in Your Camper

This is part Four of the camper and RV repair series.

Often, by the time you find water damage in your camper or RV, there is already a lot of damage inside the walls. First, fix the leak READ ARTICLE. Then you will need to patch up the whole outside of the trailer READ ARTICLE. Next you will need to replace all the rotten wood READ ARTICLE. Now, you can proceed on to insulating your RV and make it even better than from the factory.

Remove old RV insulation to prepare for new


If you have followed the previous articles, then you have already removed the old insulation and replaced any old, rotted wood and framing materials. If not, then you should do so now. Take out the old insulation that came from the factory and clean up the work area. Sometimes mice get into your trailer and cause a lot of damage inside the walls. This is not even visible in most cases until you remove the paneling to reveal the mess behind it.

The photo above shows a pickup camper that had bad water damage underneath the bed area. The rotten wood has been replaced and it is now ready for new insulation. This article will cover both fiberglass insulation and styrofoam insulation. Fiberglass normally has a higher insulation rating because you can get it a lot thicker.

Measure the thickness of your frame where you want to install the new insulation. Most campers and RVs use a 2 x 2 frame. On the ceiling, they may have about a 2.5 to 3 inch frame, tapered down to 2 inches at the walls. This makes a small peak on top of the roof to allow water to run off. You can use fiberglass insulation that is a little bit thicker than your frame, but do not go overboard. If, for example, you have 2 inch walls, you may use 3 inch fiberglass insulation. You would not want to try to stuff 6 inch insulation into the frame, this is speaking from experience. It would be a nightmare. See the photo below left. A helpful hardware associate suggested getting the thicker stuff for the 2 inch truck frame. At the store, it appears thin, about 1.5 inches thick. After you unroll it, it begins to expand a lot. After cutting it, you cannot take it back for an exchange.

If you are using styrofoam insulation, get the thickest stuff you can afford. You want a higher "R" rating for better insulation. In the photo below right, you can see 1.5 inch thick styrofoam insulation installed into the 2 inch ceiling of a trailer.



Installing a vapor barrier in your trailer

Styrofoam insulation for better warmth


First, for better results, install a vapor barrier such as seen in the photo above left. This is simply a plastic sheet that covers the frame before you install the insulation. This helps keep out moisture and wind. In the example above, a simple drop cloth was used as a vapor barrier. This was a thicker one, not the really cheap dollar store stuff. Actual vapor barrier plastic costs a lot more and a sheet of plastic is all you need. In the first photo on this page, you can see that drop cloth was used over the insulation. This was to keep fiberglass dust down and keep heat in during the time between insulating and installing the ceiling boards because it was a long work in progress and other projects were going on at the same time.

With fiberglass insulation, simply cut it with a carpenters knife or even a large pair of scissors works well. Measure the frame between boards and cut the insulation to fit in between snugly. Put the paper side out and the fiberglass side in, facing you. You may need to tape it in place using duct tape while you work if it will not stay on its own.



When working with styrofoam insulation, cut it to fit tightly into the frame and then tape it in place with insulating tape such as the aluminum tape you see in the photo. A jig saw was used to cut the insulation and worked very well.

With styrofoam insulation you have no expansion of the material as you do with fiberglass. You may have small gaps in between the foam and the trailer frame boards. Use aluminum tape in between the sheets of foam insulation and then use a spray foam to fill in larger gaps as needed.


Seal your insulation tightly

New camper insulation installed


You are now well on your way to getting your camper ready for the next season. Bookmark this page and watch for the next article in the camper and RV repair series - How to replace your RV and Camper paneling and interior trim.

Feel free to ask any questions or get help with your project on our Support Forum.

About the Author

Troy Reid


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