What Is RV Underbelly Made Of? (Coroplast Sheets For RV)
Looks may be misleading. To some, this material is a cheap corrugated plastic that can rip the moment someone breathes too hard. But the material used under the RV or trailer to protect components may be tougher than you think or than it looks.
The standard material used for an RV or trailer’s underbelly is called Coroplast. It is a tough plastic material and if treated right, should last you a long time. What throws people is that it looks like cheap plastic that can break with the first pothole in the road.
To learn more about this material used to create your underbelly, just continue to read our article. It has the information you want to know about so you can drive with peace of mind. The material is there to prevent wind resistance.
RV Underbelly Materials 101
What is Underneath a Camper?
We have come across two materials that different RV makers use to create the underbelly. The first one is corrugated sheet metal. It is a little more expensive than the alternative but it is tough and makes sure your components under the RV or trailer are well protected.
The other material used by RV makers is cheaper and lighter than sheet metal. It is called Coroplast and it may look like cheap plastic. The reviews go both ways on this product as some owners are happy with the material and others are not.
This material can be fairly strong and has lasted 8 years for some owners. Others did not last 3 years and need new supports added to the frame to hold the replacement material in place.
We did come across some flexible underbelly material that is sold in rolls. They are made with Polyethylene for the most part and they are sold in 76 and 105-inch widths. The length is negotiable.
These alternatives may not be strong as Coroplast or sheet metal but they will help stop wind resistance and aid in insulating your components from the cold.
What Material is Used on The Underbelly Of The RV?
The Coroplast option is probably the cheapest option. It comes in sheets and is easily installed on the frame of your RV or trailer, etc. It is supposed to be a very tough material and can hold up very well if installed correctly.
Another option would be sheet metal and it comes in smaller sheet sizes. The advantage of this design is that you do not have to remove the underbelly completely to work on a component.
Then the rolls of material we just mentioned are another possibility. However, the drawback to these flexible options is installation. They may not be as easy to install without using large washers to hold the material and keep it from ripping on you.
These flexible rolls are called underbelly tape or flex-mend tape and they come in different widths and lengths. Their price is very reasonable if you shop on Amazon. That marketplace seems to have a myriad of options to try out.
What is under your specific RV or trailer, etc., is determined by the brand that made the RV, etc. They will choose the cheapest material possible and while it is said these underbellies are installed for the right reason, they also hide shoddy craftsmanship.
Coroplast Sheets For RV Underbelly
This seems to be the go-to material for RV makers. They want to be able to attach the underbelly as quickly and as cheaply as they can. This material can be held in place by self-tapping screws.
These sheets look more like a cardboard box than they do any tougher material yet they are supposed to be good when you need extra insulation underneath your RV, etc. The self-tapping screws make it easier to add plastic to the frame.
The trick is to find this material in sizes that are easy to handle. Some hardware stores do sell them in 4 by 8-foot sizes and you can get smaller 2 by 3-foot sizes if you buy the Coroplast made for advertising signs.
Either way, you should have good protection underneath your RV when you are on the road. Also, the addition of the Coroplast should help your air conditioner perform better as it may help seal up some leaks that let the cold air out.
If you go this route, make sure to have help holding up the sheets so you can align them perfectly and make sure your underbelly is fully protected.
RV Underbelly Material Home Depot
You can find Coroplast at this big box store and it seems to be sold in-store as well as online. The price will depend on what size you will want the material in. Home Depot also sells flex mend and other underbelly materials.
You can use those latter options to repair any holes in the Coroplast or other materials used for your underbelly. They also sell 4 by 8 sheets of underbelly material. Since it is made of plastic, the material should not rot on you when it gets wet.
You may find an alternative called Darco that is more flexible and easier to install. The choice will be up to you and if you can get to a Home Depot it is worth looking at the stock they have on hand. Coroplast is not the best material but it may be the cheapest to use.
Talk to the experts at that big box outlet and see what they recommend. You will want something that can handle tough situations like a blown rear tire. Coroplast has been known to shred under those conditions.
There is also a pond liner that you can use as that has been put on different RVs back in the 1990s.
RV Aluminum Underbelly
There is an aluminum product that attaches to your underbelly. It is advertised as a replacement for the original aluminum sheets used on Airstream trailers. This material is supposed to be better at resisting corrosion and dents than the original materials used for that brand of RV trailer.
The cost seems to be reasonable as it goes for roughly $179 per roll and the rolls measure 4 by 6 feet and 4 by 12 feet. Do not quote that price as the longer roll may be more expensive.
That seems to be the only option available and marketed as RV aluminum underbelly material. You may find good aluminum options at those businesses that deal in products made from that material.
One example would be talking to a siding company. After all the underbelly is a siding issue. It is just laying horizontal instead of vertical. The installation would be more difficult and you would need some support if you are going to add this material yourself.
Most retailers we saw when researching for this topic,. all want to sell the flexible roll like Darco. These seem easier to stock than alternatives like Coroplast.
AccessiBelly RV Underbelly
This is the new style of underbelly material. Instead of having the technician cut holes in a game of hunting and peaking, this material allows technicians to only drop one panel and avoid cutting holes in the material.
Like Coroplast, this is made from corrugated plastic but its design is to give you easier access to your components, hence the name. However, there is a big drawback to this option. It seems that while this design provides easy access for a technician to make repairs, it can drop without notice just as easily.
You end up with a destroyed panel when this happens. They also seem to crack and dent very easily as another owner was not happy to see what was going on underneath his RV when he changed a tire.
This concept may be a good idea but it looks like the design flaws are going to keep a lot of customers away. But then most brands of underbelly construction materials do not use the toughest material possible. They all seem to have these types of flaws.
To help hold these panels in place, you may have to use larger washers to keep the screws from working their way through the holes.
Underbelly Armor RV
We cannot find too much information about this product. We say a Forest River spec sheet that mentions this product. All it says is- and underbelly armor combine to create a perfect balance of size, space, features and luxury.
The same spec sheet only mentions that there is a fully enclosed underbelly and does not discuss the construction materials used to create that area. Any mention of RV Armor refers to RV roofing materials that are supposed to be strong.
We did find a video that explained a little bit about this product. It is just another corrugated version of underbelly material. The big difference is that it is laminated for extra protection.
This material comes in long rolls that cover the whole frame and it comes in panels so you do not have to remove the whole underbelly to repair one component. The material is screwed into place instead of being nailed.
One drawback would be if the installer used too few screws. If so, then the wind has a good chance at rip[ping it off and causing you an extra repair bill you hadn’t counted on.
RV Underbelly Fasteners
There are several ways to attach the underbelly material to your RV’s frame The most popular method is self-tapping screws with built-in washers. They do not look like the strongest screws you can use but they seem to work in a pinch and are probably the cheapest option available.
Their real nail is metal to metal roofing screws or lath screws. They are used a lot but it is hard to say how good they are and how long they will last. These screws are Jayco Part Number 0152303 – Screw, panhead quad Tek 2 #8X1inch epigard with neoband washer made by Wesco Industrial and they come in boxes of 7500.
Nails used to be used but there may have been too many complaints about the nails. They are very difficult to remove and some owners used a crowbar, cat’s paw, hammer and a grinder to get their nails out.
Some nails will come with a hex head so you can use a drill to back them off a little way then pry them out the rest of the way.
RV Underbelly Adhesive
There is tape available but these adhesive options are more for repairing holes and slits than they are for holding underbelly material in place. Some owners suggested using the screws first and then covering the screws with tape for a better hold.
The tape is found in all different sizes and lengths and is made by different brands. Gorilla Glue makes one option and it says that its tape instantly blocks water, air and moisture from your underbelly.
The tape is usually black and goes on nice and easily. There is a spray adhesive but it is uncertain how well it will hold anything. These different tape options are sold wherever RV supplies and parts are sold.
Sometimes you can find this adhesive in gray and white. The tape is advertised for repair work and not for securing the underbelly material. You just have to find the location with the best options at the lowest price.
Some Final Words
The underbelly material is said to help with wind resistance as well as protect your components. But some owners feel that the material is used to conceal bad construction work on the part of the RV maker.
However you look at it, having an enclosed underbelly does help with fuel efficiency as well as air conditioner efficiency. It is a good option to have installed as long as you pick the right material.
Coroplast may be the cheapest but it is still nice and strong and it does not add a lot of weight to your trailer, etc.
