Foam Board or Rubber Mat For Under Camper?

[a_flyfisher]

I have ordered a new Northern Lite camper for delivery next spring.

I see on Northern Lite's website they recommend putting a 3/8" soft rubber mat in your truck bed under the camper. The dealer that I am getting the camper from includes a foam board instead of a rubber mat. I believe he said it is 1" thick, which they prefer to use and say it is better to use than a rubber mat.

Is one of these - a rubber mat or a foam board - better than the other? Or will they both serve the same purpose?

Don't know if it matters, but I do have factory installed rails for a 5th wheel installed under my truck bed, and the capped holes where the 5th wheel hitch mounts protrude somewhat above the truck bed's surface - I didn't measure them, but believe they protrude just 1/2" or so.

Appreciate your thoughts.

John

P.S. I don't have a lot of confidence, generally speaking, in my Dealer based on prior experiences there.

[capeman]

I also use a mat and have to use foam for clearance issues....NP for 6 years

[TxGearhead]

Got the 3/4" CDX cut yesterday. Three pieces....1 in front and 2 in the back. Notched it around the tailgate area to keep it in. I almost extended it beyond the tailgate, but thought it would be convenient to be able to close the tailgate and have it all in place with the mat on top so I could just drive under the camper.
Decided against fishing this morning so I can paint it.

[bigfootford]

TxGearhead wrote:
10-4 Thanks.
What seemed to be attacking pad?

The screws and just the bottom of the camper rim the supports the weight of the camper and the bottom rim around the front and passenger

Going around corners etc wii put forces of the weight into the sides or when putting the brakes on the weight of the camper will be trying to move forward and down in the front....

Like HMS said... STAMPING... If you need to raise the camper up do foam on the bottom then Plywood and then the top with rubber if you want...

Jim

[TxGearhead]

10-4 Thanks.
What seemed to be attacking pad?

[bigfootford]

TxGearhead wrote:
Bought 3 sheets of 3/4" CDX plywood this afternoon. Should have them fitted tomorrow afternoon and maybe started on painting.
I'll put the bed mat on top of the plywood.
Thanks for all the good info and advice.

Perfect plan....

When I did mine I had the ply and pad... The pad got chewed up around the front, especially the passenger side so I removed it about 10 years ago and found the plywood was enough.



Jim

[TxGearhead]

Bought 3 sheets of 3/4" CDX plywood this afternoon. Should have them fitted tomorrow afternoon and maybe started on painting.
I'll put the bed mat on top of the plywood.
Thanks for all the good info and advice.

[HMS_Beagle]

On a sharp corner, the camper is only supported by its edge, compliance of all the materials involved spread this out from a line to a narrow area, width difficult to know. Let's say 2": then it is supported by about 200 sq in. Now the foam has to support 22 psi on a 4500 lb camper. Type II EPS is spec'd less than that, but there are denser foams that are much higher. If you've been doing it for years and the foam isn't compressing further then it is strong enough by experiment. Also as it sinks into the foam it will be supported over a larger area, so maybe self limiting. Anyway it can work, just not a slam dunk.

I am quite sure that Bigfoot believes their camper is strong enough to take the stress riser presented by the end of the bed. I have seen stress cracks there on old Bigfeet though. I ran the plywood about 7" beyond the edge of the bed. The plywood is flexible and much beyond that is simply going to have flexed away and do nothing. My assumption is that a few inches would bend into a curve and spread the extra load of that stress riser over several times the area. The dilemma is that bed mats stop at 8'. I had a fitted bed mat, due to the rails on my plywood I had to cut the bits forward and outboard of the wheel wells. So I lay those behind the bed mat on the plywood overhang, so that there is no gap between plywood and camper.

I know that pressure is being applied by the camper there, because I have not lost the extra bits of bed mat and would have, if they were floating free. I've searched for bulk bed mat material to try to get a single piece oversize mat, but haven't found one yet. I'm aware of the horse stall material used by many, but I'm really looking for the thinner bed mat material with the bumps on the bottom (which allow the plywood to dry). I will probably just end up buying two bed mats and cutting them together.

[GoinThisAway]

I've been hauling a Bigfoot 2500 for 8 years. Started with just a 1" thick 4'x8' bed mat but found that the bumpouts at the rear were contacting the unprotected bed. I could tell because the aforementioned screws on the bottom of the camper were digging into the Line-X liner in these areas. So I cut some pieces of rubber from a thick door mat to fit into these areas and tied them to the rear bed tie down loops. I later added a piece of 1" foam board under the rubber mat and made sure to add foam pieces under the bumpouts too. The camper overhangs the truck bed by about 2' but I've had no problems with the foam/mat ending at the end of the truck bed. I'm sure it's designed to handle the lack of support beyond the truck bed. And that's why it's important to support the bumpout areas at the back as this is the last area of support before the overhang.

[Rubiranch]

dunegoon1 wrote:
Plywood is not a good idea in Oregon due to the moisture damage, in my experience.

makes perfect sense

[TxGearhead]

Jim and Jon: If you have the plywood overhanging the bed, and you put the mat on top of that, does that create a void where the mat is not as long as the plywood? I like the idea of supporting the very rear of the camper but I don't think it would, if I'm reading it right. I'm assuming you have a mat that is fitted to your truck and it stops at the tailgate.
I'm thinking maybe throw my mat in first and put the plywood on top. Maybe the mat will help with the irregularities of the bed. Or...more thinking out loud....Bigfoot recommends a mat or plywood to protect the truck, I assume they built the camper to be structural good with no support for the overhang?

[dunegoon1]

I've used a 3" structural foam board for many years and it had been just fine. Concerning foam: Yes it does compress here and there due to the corrugations in the bed, but that's exactly what you want. On the top side, it also shows indentations from screws and some lap joints (Bigfoot 2500), but again that's exactly what I want it to do. It's has to support less than 1 pound per square inch, and after it's initial conformation, it's supporting the camper equally on every square inch. I need the extra height to clear the cab, so the weight of plywood, boards, and a horse mat was a couple of hundred pounds and a P.I.A to take in and out whenever I wanted to use the truck for "actual work". Foam has been good for me and cheaper as well. I am not sure how foam would act if only an inch thick, though. For a "no rise" situation, I might go for some slats and a thin rubber mat. Plywood is not a good idea in Oregon due to the moisture damage, in my experience.

EDIT: I also cut extra pieces of foam to support the Bigfoot wings. They are light and easy to deal with. Nothing moves.

[Rubiranch]

A good friend of mine has been selling campers for over 35 years and is a Lance dealer.

He told me a sheet of plywood works fine.

[TxGearhead]

Y'all ain't nothing but good.
I have a new project!!!

[bigfootford]

HMS Beagle wrote:
I have not had the plywood slide backward, but it you look closely at the picture, my plywood is cut around the tailgate opening such that it is locked in by the tailgate frame. Actually it's pretty hard to see in the picture but it is there. It can't slide backwards. I think I would worry about this otherwise, particularly since it is on a poly liner which is a bit slippery. Still, the camper is held forward by the tie downs so I don't think the plywood would try to crawl out from under.

I think the Bigfoot decal is due to all the screws underneath. These will for sure tear up the paint on the bed. If you use plywood and no rubber, you will get a nice imprint of the screw heads in the plywood in very short order.

My plywood is shaped like Jon's..... HMS. Never had mine shft... There is quite a bit of weight at the rear.. The plywood back there is needed for support of the entire rear... I actually cut the plywood to be about 1.5" over the rer of the bed. I think this helps not having an abrupt edge. The plywood bends slightly so there is no sharp edge.

Jim