How To Keep RV Underbelly Warm (RV Underbelly Insulation)

One thing that can ruin a vacation is when the cold out battles your heater or the heater fails. You can protect yourself by insulating the underbelly of your RV or trailer. That way you have another line of dense when it is too cold outside

The best way to do this is to use the right insulation material. You can use hard insulation boards or even fiberglass. But both products need to be handled with care. Or you can use spray foam to get into those little nooks and crannies that let air in.

To learn how to apply these solutions and what other materials you can use, just continue reading our article. It has that information you should know about. Take a few minutes to see how this information should keep you warm this winter.

How To Keep RV Underbelly Warm


To keep your underbelly warm this winter, you have plenty of options. For some skirting is the answer. This material will block the wind and cold from getting underneath your RV or trailer helping it to stay warm all season long.

You can also use heaters underneath your RV or trailer. These devices go a long way to make sure your tanks and plumbing do not freeze on a cold night. The drawback to this option is the extra expense.

A final solution would be to insulate the underbelly to make sure the cold stays away from your floor and everything else located under your RV, etc. You have plenty of options available from hard insulation board, to flexible insulation materials, to traditional fiberglass to spray foam.

The option that you choose to use will depend on how cold it gets in your camping area, what materials you can afford to use and how big your RV or trailer is. Not to mention the design of your RV or trailer.

RV Underbelly Insulation Options

As you have read, there are quite a few insulation options available to you. The key is to choose the right R factor and each option should have several R factor levels to choose between. How high an R factor you get will depend on how cold it gets in your camping area.

Basically, there are 3 types of underbelly insulation you can use. You can use heat tape or similar products but those only cover your pipes and tanks and do little for the rest of your RV, etc.

A rigid foam board is the cheapest option you have. It is easy to attach to your RV, etc., and can be found in moisture-resistant formats. They are fire-resistant as well but do exhaust a harmful odor if your RV does catch on fire.

The next type will be regular fiberglass. It goes into your traditional home so you know that it can be frustrating to work with at times. It is a good material as it does keep the cold out.

The final type will be spray foam insulation. This is also easy to apply and can coat those corners and little nooks a lot easier than the other options. Plus, you save time as you do not have to measure and cut the material to make it fit. You just spray it on everywhere and you are covered.

Best Insulation For The Underbelly of RV


They are all good but we favor the spray foam option. The reason for that support is that this material will make sure every inch of your underbelly is insulated without a lot of heavy work involved.

The other options are good but there is always the risk of damaging a board, tearing the fiberglass or wasting a lot of time cutting to size. The key is to get the spray foam in the right R factor. You do not want to go light here as that will mean that some cold will eventually get through to your flooring.

Also, you may have to do the insulating yourself if you go with the other two options. You can hire someone to do it but there is no guarantee they will do quality work. With spray foam, you can make sure the company does a good job and covers the underbelly as you want.

How To Insulate The RV Underbelly

There are different ways to do this task. The following 5 steps are just one way to do it:

1. You will have to measure the dimensions of the underbelly to see how much material you will need. The spray foam companies will need to know the square footage to give you an estimate.

2. Remove the underbelly from its position and detach different connections, wiring and so on. Make sure to properly label the parts you take off so that you can put them back when you are done insulating the area.

3. Cut and measure the insulation if you are not using spray foam. Then attach each section to the frame of the RV, etc. or go inside the joists or cross beams to cover every inch of the underneath section of your RV, etc.

4. Once the insulation is attached where you need it, put everything back in its rightful spot. Check for leaks, gaps and so on patching those before placing the underbelly back in place.

5. Clean up the area.

How Does a Heated Underbelly on an RV Work?


In many cases, the heated underbelly system works just like the rest of your heating system in your RV or trailer, or even your traditional home. There are hidden vents attached to the duct work that sends the heat into your underbelly area when you turn the heater on.

These vents put the heat where it is supposed to go so that the area underneath your RV, etc., remains nice and warm while providing you a little barrier from the cold. Some RVs only have a flex hose to do the heating work for you in this area.

The drawback to this underbelly heating system is that the gaps under your RV or trailer will let the heat out and the cold air inside. It is a very inefficient system which means you may have to use other insulation options to keep that area warm.

Some owners only have heating blankets in that area making the heated underbelly option smoke and mirrors. There is heat but not a very good system to deliver that heat.

How To Heat The RV Underbelly

If you do not have a heating system already installed, then you can go to the standard independent little heaters. Place one or two underneath your RV, etc., and turn them on. They will keep the area nice and warm. However, the drawback to this option would be the extra expense those electric or propane heaters will cause you.

Another drawback to this system is that those heaters may prevent the furnace from turning on and protecting the components under the flooring. There are other options you can use.

There is heat tape and heat blankets that attach to key parts to keep them from freezing over. These devices should not interfere with the furnace operation and be a nice complement to it.

This is not going to be an issue if you do not do any cold-weather camping in regions that get down below freezing. Your camping area will play a role in if you need to heat the underbelly or not.

Best Way To Insulate RV Underbelly


As we said earlier, we liked the spray foam option. It will cover everything and not create an extra expense like heaters, heat tape and blankets will do. Then the fiberglass and different hard/flexible insulation boards are a great option as they can cover the area between the cross beams on your frame.

Which method you choose will depend on how much work you want to do, how much you want to pay for labor and how much the materials will cost you for your size of RV or trailer.

The size of your trailer, etc., will be a strong factor in the overall cost. It may be best to use spray foam so that you do not have a lot of small pieces left over, going to the landfill.

It will be up to you to decide which is the best insulation option you use. Talk to the experts at the different insulation outlets that sell these different products to get their advice and recommendation.

Some Final Words

If you are going to camp in cold weather, then it is best to make sure your underbelly is fully insulated and heated. The two lines of defense should protect your components and keep plumbing and tanks from overheating.

Check the costs and make sure to measure the area so you can get an accurate quote on the total materials cost. Then see if that expense will fit your budget or not.

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