Foam Board or Rubber Mat For Under Camper?

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

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.

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

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

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

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.

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.

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.

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

makes perfect sense

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?