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.

[HMS_Beagle]

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.

[TxGearhead]

I thought this horse was about dead, but no, I want to beat on it some more.
After reading and re-reading posts, especially HMS BEAGLE, I'm thinking I could be creating an issue. My Bigfoot has a 3" kickout at 6' from the front that goes behind the wheel well, then the rear skirt kickout behind that. The way I'm loading now with the 4x8 plywood and the rubber truck mat on top of that, the edge of the camper is not supported behind the wheel well. I created a void behind the wheel well the depth of the plywood. I'm thinking maybe just leave the plywood at home and use only the mat since it would provide continuous support behind the wheel wells. But I like the idea of spreading the load across the bed corrugations and am not sure if the mat alone would do that. Bigfoot has a decal on the back of the camper that says to protect the truck bed use a rubber mat or plywood.
For those that have cut plywood in pieces, have you ever come close to having one of the pieces slide backwards? I doubt it would with the weight of the camper on it, but....

[HMS_Beagle]

That is a drop in polyethylene liner. I used the same plywood in the '99 truck which had a spray in liner. It too had a poly liner to start, the camper shifted (admittedly in challenging conditions) so following some advice here I removed it and did the Line-X spray in. The camper moved just as much, hence the plywood with blocks or rails. In the new '15 truck, I went back to the poly liner as they protect the bed better than the spray in. Sadly, the poly liner (same brand and model) now is about 1/2 or 2/3 the thickness of the old one. That makes it a little "softer" under the load. With the plywood though, it is still not an issue - the load is spread over a large area of the liner and bed and there is no difference in movement compared to just the steel bed.

[bigfootford]

HMS Beagle wrote:
I put plywood where ever the camper could touch the bed. Not sure on the NL, but on a Bigfoot they typically get wider aft of the wheel wells, so I put plywood there too. I also extended it about 6 inches over the bed edge, as I have seen fiberglass campers get a bit stressed (cracked gel coat) at this "stress riser". The plywood spreads this stress out a bit. While I was at it, I added blocks or cleats to the ply to keep the camper centered.

At the front, I like the idea of a board at least 1" thick for the camper to bump against. If it has the usual rubber bumpers up there, on heavy braking those two small pads are putting a lot of point pressure on the thin sheet metal of the bulkhead. Again, a board will spread this out a bit.

In the picture you can see the black dots imprinted from the DeeZee mat. Note that there is significant load outside of the wheel wells aft. The plywood is in three pieces (bulkhead to mid wheel well, left and right halves to the back) to make them easy to remove. They fit fairly tightly to the sides to keep from shifting.

Nice description of the subject.

I notice that you have the spray in bed liner... Your fit for the plywood keeps it from shifting. Nice job.

Correct about the perimeter fiberglass imprint and the stamping those screws on the wood!

Jim

[bigfootford]

a_flyfisher wrote:
All of you guys have been great with you comments and suggestions.

Since this will be my first truck camper, as I said earlier in this thread, I am inclined to simply follow the manufacturer's recommendation and use a sheet of plywood and a soft 3/8" rubber mat on top of it.

Now, I assume that a 4'x8' 1/2" plywood is sufficient, topped with a 4'x8' rubber mat, and I don't have to cut out plywood pieces to fill the entire truck bed, or get one of those custom mats that cover the entire truck bed. Correct?

(I guess I'm learning here that I might want to consider some type of further blocking around my camper in the truck bed if I find it shifts after being secured with tie downs, etc. And, I rather like the idea of cutting another piece of rubber matting to separate the camper from the front of truck bed.)

Yep, have to cut that plywood to fit. Mine is 3/4 ply cut and shaped for wheel wells, 4 pieces makes it easy to get out.

I have no other blocking to prevent sliding, shifting around.. My tiedowns are just old Happijac's.

Never had my camper shift much. When I first load the camper and drive it for a bit I might have 1 or 2 tiedowns loosen a bit. A bit would be maybe enough turns for about 1/4 inch. Like I said, I have been over some prolonged rough roads...

Jim

[HMS_Beagle]

I put plywood where ever the camper could touch the bed. Not sure on the NL, but on a Bigfoot they typically get wider aft of the wheel wells, so I put plywood there too. I also extended it about 6 inches over the bed edge, as I have seen fiberglass campers get a bit stressed (cracked gel coat) at this "stress riser". The plywood spreads this stress out a bit. While I was at it, I added blocks or cleats to the ply to keep the camper centered.

At the front, I like the idea of a board at least 1" thick for the camper to bump against. If it has the usual rubber bumpers up there, on heavy braking those two small pads are putting a lot of point pressure on the thin sheet metal of the bulkhead. Again, a board will spread this out a bit.

In the picture you can see the black dots imprinted from the DeeZee mat. Note that there is significant load outside of the wheel wells aft. The plywood is in three pieces (bulkhead to mid wheel well, left and right halves to the back) to make them easy to remove. They fit fairly tightly to the sides to keep from shifting.

[TxGearhead]

This is my 2nd TC but the first one was in 1983 so I'm certainly no authority. I'm using a 4x8 sheet of 1/2" plywood with a DeeZee truck mat from Tractor Supply on top of the plywood. The mat covers the entire bed, including the areas around the wheel wells. It's not soft by any means. I'm using TorkLift Fast Guns tiedowns and so far haven't noticed any shifting.

[a_flyfisher]

All of you guys have been great with you comments and suggestions.

Since this will be my first truck camper, as I said earlier in this thread, I am inclined to simply follow the manufacturer's recommendation and use a sheet of plywood and a soft 3/8" rubber mat on top of it.

Now, I assume that a 4'x8' 1/2" plywood is sufficient, topped with a 4'x8' rubber mat, and I don't have to cut out plywood pieces to fill the entire truck bed, or get one of those custom mats that cover the entire truck bed. Correct?

(I guess I'm learning here that I might want to consider some type of further blocking around my camper in the truck bed if I find it shifts after being secured with tie downs, etc. And, I rather like the idea of cutting another piece of rubber matting to separate the camper from the front of truck bed.)

[bigfootford]

bigfootford wrote:

HMS Beagle wrote:
Different models of Bigfoot have different structure underneath, but the common theme is that the only reliable support is across the front and down each side at the perimeter. Then depending on model, some crossing structure near the rear of the bed.

I have used a plywood sheet in the bed with a pickup bed rubber mat on top, the type with the rubber nubs underneath. The plywood sheet is painted white. After a few hundred miles, you can clearly see the black imprint of the rubber nubs on the white plywood where the pressure from the camper is applied. The pattern was a bit different in detail between my 9.6 and my 10.4 model but similar in general.

Foam has the compressive strength necessary, provided the load is spread over enough area. The only way to insure that is to put plywood between the foam and camper, 1/2" plywood should be plenty.

When you go around a corner or the camper rocks while entering a service station ramp at an angle, most of the weight of the camper will be on one edge. Hit a 1.2G bump at the same time, you are getting pretty close to compressing the foam. With 1/2" of plywood, you are effectively spreading the load to 2 or 3x the area adding considerable safety factor. From the bed up I would do: foam, plywood, rubber mat, camper.

I 100% confirm and agree...

No foam between the camper and bed of a Bigfoot... And I would say even the Northernlite.

Jim

[bigfootford]

HMS Beagle wrote:
Different models of Bigfoot have different structure underneath, but the common theme is that the only reliable support is across the front and down each side at the perimeter. Then depending on model, some crossing structure near the rear of the bed.

I have used a plywood sheet in the bed with a pickup bed rubber mat on top, the type with the rubber nubs underneath. The plywood sheet is painted white. After a few hundred miles, you can clearly see the black imprint of the rubber nubs on the white plywood where the pressure from the camper is applied. The pattern was a bit different in detail between my 9.6 and my 10.4 model but similar in general.

Foam has the compressive strength necessary, provided the load is spread over enough area. The only way to insure that is to put plywood between the foam and camper, 1/2" plywood should be plenty.

When you go around a corner or the camper rocks while entering a service station ramp at an angle, most of the weight of the camper will be on one edge. Hit a 1.2G bump at the same time, you are getting pretty close to compressing the foam. With 1/2" of plywood, you are effectively spreading the load to 2 or 3x the area adding considerable safety factor. From the bed up I would do: foam, plywood, rubber mat, camper.

I 100% confirm and agree...

No foam between the camper and bed.

Jim

[HMS_Beagle]

Different models of Bigfoot have different structure underneath, but the common theme is that the only reliable support is across the front and down each side at the perimeter. Then depending on model, some crossing structure near the rear of the bed.

I have used a plywood sheet in the bed with a pickup bed rubber mat on top, the type with the rubber nubs underneath. The plywood sheet is painted white. After a few hundred miles, you can clearly see the black imprint of the rubber nubs on the white plywood where the pressure from the camper is applied. The pattern was a bit different in detail between my 9.6 and my 10.4 model but similar in general.

Foam has the compressive strength necessary, provided the load is spread over enough area. The only way to insure that is to put plywood between the foam and camper, 1/2" plywood should be plenty.

When you go around a corner or the camper rocks while entering a service station ramp at an angle, most of the weight of the camper will be on one edge. Hit a 1.2G bump at the same time, you are getting pretty close to compressing the foam. With 1/2" of plywood, you are effectively spreading the load to 2 or 3x the area adding considerable safety factor. From the bed up I would do: foam, plywood, rubber mat, camper.

[bigfootford]

adamis wrote:
Jim I do appreciate the thoroughness of your response and I accept that you have mileage and experience. FYI, you mentioned a picture of screw compression in the plywood but I don't see the picture in your post just the one picture of your tank.

Covered Wagon I understand precisely what is being described with a fiberglass camper and where the weight is distributed. What I have observed in my own application and the several thousand miles I've driven so far is that I have not had the issues that Jim encountered. It could be that I've not driven far enough or that I'm using a different type of foam (Jim didn't cite what he used) with a higher PSI rating. There could be a multitude of reasons for the difference in outcomes.

Others have had the same success as myself and that strikes to the point of my post which wasn't to cast doubt about Jim's experience but rather that his experience is not the only observation.



Going back to my own application, the reason I resorted to pink foam at all was because I needed to add 4" of height and doing that with plywood would have added over 350 lbs. I might have built some sort of platform with 4x4s to support the edges but resources and tools were unavailable at the time.

That being said, I will take Jim's experience to heart and keep an eye on my setup to see if I eventually encounter the same issues he has observed.

If I needed to elevate that far I would probably do the pink foam and then 3/4 plywood..
Just my opinion.

As for the picture I was just showing how the tanks are suspended... They sit on low density foam, then the thin fiberglas plate. So the bulging weight of the tanks need support.. The foam you are using will be fine for that. Can not use anything else like 2x4's across the bed or such.. Need support like you did. Do not want to stress those STRAPS!!!!!!!!!!!

Someday I need to take some pictures of what has happened to my plywood.. It is cut into sections to traverse around the wheel wells. I actually have a big piece in front of the wheel wells and then another that is shaped to go around the wheel wells and just over the rear of the bed.... After 12+ years it still has no rot but my camper and truck have a CAVE.

We did an Alaska trip 2 years ago... Clear up the Dalton Hwy to Prudhoe Bay... The truck, camper and everything took a beating but after reviewing everything the BF and everything hung together... A wow trip for sure and a challenge for our old 94 f250... Heck after that trip we did a full cross country trip to Fla... All systems go!

Jim

[adamis]

Jim I do appreciate the thoroughness of your response and I accept that you have mileage and experience. FYI, you mentioned a picture of screw compression in the plywood but I don't see the picture in your post just the one picture of your tank.

Covered Wagon I understand precisely what is being described with a fiberglass camper and where the weight is distributed. What I have observed in my own application and the several thousand miles I've driven so far is that I have not had the issues that Jim encountered. It could be that I've not driven far enough or that I'm using a different type of foam (Jim didn't cite what he used) with a higher PSI rating. There could be a multitude of reasons for the difference in outcomes.

Others have had the same success as myself and that strikes to the point of my post which wasn't to cast doubt about Jim's experience but rather that his experience is not the only observation.

Going back to my own application, the reason I resorted to pink foam at all was because I needed to add 4" of height and doing that with plywood would have added over 350 lbs. I might have built some sort of platform with 4x4s to support the edges but resources and tools were unavailable at the time.

That being said, I will take Jim's experience to heart and keep an eye on my setup to see if I eventually encounter the same issues he has observed.

[covered_wagon]

Nice explanation BigFootFord. I've personally experience what you are saying with my NL camper and is exacerbated by the low point of truck bed corrugation or lack of support along the load points you are talking about.

Adamis has a good point and put a lot of time in his post but I don't think he understands the situation with a plastic shell camper.

[bigfootford]

adamis wrote:

covered wagon wrote:

bigfootford wrote:
Bigfoot's and Northern Lite's, NO foam!
I have the same plywood in the bed of my truck for about 12 years...
I used a 1/2" rubber pad for a few years but the camper dug into it and was stressing the bottom perimeter of the camper.... Bigfoot has a thin fiberglass bottom cover for access to the holding tanks. NL does not have that but the perimeter is where the weight is distributed and is where it is the strongest!

Jim

Nice Post..... and solid advice.:)

Sorry but I believe it incorrect to come up with blanket statement such as "No Foam" and consider it solid advice without looking into the details.

Not all foam is made the same and the foam used by myself and others (and used with success) can be well suited for this application. The concern raised in this thread was whether foam was suitable for fiberglass campers because the structural support is at the walls of the base of the camper.

In my case I used FOAMULAR® 250 Extruded Polystyrene (XPS) Rigid Foam Insulation comes with a minimum compressive strength of 25 PSI. Just looking at the outside 2" edge of foam supporting the camper walls that is 2"x96" for a total area of 192 square inches with a 25 PSI rating giving me 4800 lbs of compressive strength PER side for a total of 9600 lbs of compressive strength to hold the edges of the camper. If I was to look at the total support of the entire area under the camper using the same foam I'm looking at an area of 48"x96" for a total supported area of 4608 square inches giving me a total minimum compressive strength of 115,200 lbs.

The point here is that the RIGHT type of foam is well and capable of supporting the weight requirements we are discussing. If one just needs to raise the camper by an inch or so then a sheet or two of plywood makes sense. However, in my case I need 4" of height and that would have taken over 5 sheets of plywood and added 362lbs of weight. Of course I could have built some type of structural support frame to shave some weight but then I'm stuck guessing where to try to support the underside of the camper and where not to.

That being said, if this is a matter of warranty and the manufacturer specifically states don't use foam or it will void the warranty then by all means, abide by the manufacturers recommendation. But... if you have a camper not under warranty and need to add significant height to clear your cab then pink foam is a viable option if you use the right product.

I see that you have a new to you Bigfoot camper, congratulations.

The following is not directed at you and your rebuttal post.. I want folks to know what goes on with foam and the Bigfoot campers...

After 16 years and close to 200,000 miles with the same camper seeing it STAMP itself into Foam, Rubber and plywood does count as experience. I have used a few types of foam.. You should see what the Bigfoot does to plywood and a 1/4" rubber pad let alone Foam.

One has to know how the Bigfoot is made to understand my statement!

1. The bottom of the bigfoot is not a solid piece of Fiberglass.

2. The bottom perimeter of the BF has only a 1.5"-2 inch lip across the front, down the drivers side to the rear of the camper, across 1/4 of the back...There is a 2ft opening for the water tank which is L shaped and is across the front of he camper and down the drivers side, and Black and gray at the rear. All of which can be dropped down from under the camper. There is no other hard support for the bottom of the camper around this part of the perimeter. The passenger side perimeter is fiberglass but only the perimeter is weight supporting.

If you look at the impression on my plywood you would see that the screws that hold the thin bottom access plate covering the tanks dig into the plywood and there is compression around that perimeter.

This said, the foam only supports this perimeter....and over time driving the foam gives in and compresses... When that happens the thin plate fiberglas gets stressed, the screws start cutting into the thin plate... Most of the foam compression occurs everywhere the access hole is... The passenger side does not compress as bad because there is no access plate and has some reinforcement. So when the foam compresses on one side and the front the camper sits twisted and will have a tendency to rock...

I do not have pictures to show how the Bigfoot is made at the bottom.

The Bigfoot is the only camper built this way...as far as I know...

Here's how the fresh water tank is accessed and how it is secured.. 50 gallons of water <>400lbs...



This all said, the Northerlite camper has a solid underside but I doubt that it is as thick as the bottom edge! So I would not recommend foam under them either. Many campers have a matrix of wood framing that the bottom plywood is attached to thus distributing a lot of the weight over the entire bottom of the camper.


Jim