Coast Resorts Open Roads Forum: Foam Board or Rubber Mat For Under Camper?

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Topic: Foam Board or Rubber Mat For Under Camper?

Posted By: a_flyfisher on 10/25/16 03:01am

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.

a_flyfisher

Posted By: SugarHillCTD on 10/25/16 03:37am

There have been pictures posted where foam board deforms in areas of concentrated camper weight but doesn't deform and actually pushes up into less supported areas of the camper bottom.

On the other hand I have not seen any posts about any heavy rubber mats doing any damage. I have used one under all 5 of the TCs we have owned without any problems.

IMHO, if a foam board is used a sheet of plywood over it would be a good idea.

Posted By: a_flyfisher on 10/25/16 04:05am

SugarHillCTD wrote:

Thanks for the reply. I guess I should have done a search before making my post. I just did, and here is one post that I found:

"I asked this very question of Northern-lite. Here is what I was told: foam has too much give to it and can cause stress on the camper. He told me to use plywood, followed by a 3/8 inch soft rubber mat. I had a foam board, but got rid of it after NL said the preference is plywood. "

I think I will follow NL's recommendation. Better to follow their suggestion, I think, than not follow it and then have problems downs the road.

Posted By: gbopp on 10/25/16 04:28am

a_flyfisher wrote:

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

I think you answered your own question....

Posted By: Wardster on 10/25/16 06:47am

I have a NL and use one of the thick horse stall mats available at you local Tractor Supply store. It is dense enough to provide the necessary support for the TC and doesn't allow it to slide around in the bed of the truck. With respect to plywood, I would be concerned about the long-term effects of its exposure to the elements.

2016 Northern Lite 8'11" Q Classic Special Edition
2003 GMC 2500HD Crew Cab 4x4 - Duramax/Allison

Posted By: Bedlam on 10/25/16 07:12am

I use thicker horse stall mats around my gooseneck hardware mounted in the bed. They add some weight but do a good job of keeping the camper floor off the hardware and keeping it from shifting.

Chevy Sonic 1.8-Honda Passport C70B-Host Mammoth 11.5-Interstate Car Carrier 20-Joyner SandViper 250-Kawasaki Concours ZG1000-Paros 8' flatbed-Pelican Decker DLX 8.75-Ram 5500 HD

Posted By: billyray50 on 10/25/16 07:13am

I have and still use both.

Posted By: punomatic on 10/25/16 07:27am

When I first put my TC on my F350, I discovered that the cabover was resting on top of the cab. What to do? After some research, I got a 4'X8'X2" sheet of insulating foam for the truck bed. Someone told me the foam would not support the camper, but in doing the math I discovered that the load on the foam was about 1 lb. per square inch. I used that foam sheet for several years before it appeared to be deteriorating. I sold the camper, but had I not, I would have simply replaced the foam sheet (about $40 IIRC).

DW and Me
2016 Riverside White Water Retro 195
2014 Nissan Titan SL Crew Cab
Formerly, I used to work for the department of redundancy department.

Life in Black and Blue

Posted By: a_flyfisher on 10/25/16 07:41am

I am not concerned,about plywood weathering. My truck and camper will be stored inside except when I'm using them, which will be mostly during the summertime in Montana. I will look at thos rubber mats at Tractor Supply. There is one just down the road from me.

Posted By: covered wagon on 10/25/16 07:57am

I have a NL camper. Don't use rubber matts for horse stalls because the corrugated truck bed is bent right where the camper needs its support. Bent down with a valley corrugation right at the side support walls of the camper when centered in the truck bed. That's where most weight is and needs to be held up/ supported there.

I use 1/2 inch plywood with 1/4 inch strips in the low spots to bring the key areas of weight up level with the higher corrugation in the truck bed, if that explains it.

Another key area where the truck bed corrugation fails to support is the front corners weighted down from the cab over. Just place some 1/4 inch plastic or wood blocks under the plywood to bring it up flush with the rest of the bed.

* This post was edited 10/25/16 08:07am by covered wagon *

Posted By: Tizi on 10/25/16 08:18am

I called NL about this and was told: only use plywood to raise the camper, not foam. 3/4 inch plywood, with rubber matt on top.

2008 Dodge Ram 2500 QC 4x4 - HEMI
2007 Northern Lite 10.2 RR
Tizi's Transformer by Whazoo

Posted By: Grit dog on 10/25/16 08:20am

Don't listen to the dealer if he's saying foam is required for support. That means the camper realistically won't support its own weight on a flat hard surface without some issue or deformation. Which I hardly think is the case.
To get around your hardware in the bed, horse mats cut out for the rails, plywood cut out for the rails topped with a bed mat or possibly those clip together rubber floor mats in lieu of or on top of plywood. Object is a non skid surface so the camper doesn't slide around.

2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

Posted By: a_flyfisher on 10/25/16 09:46am

Possibly, there was some misunderstanding about how my Ford truck is set up for 5th wheel use. The rails for the hitch are mounted on the frame of the truck, UNDER the truck bed, not above the bed as these hitches are typically mounted in the truck bed. As a result, the hitch sits INTO, not on top of the bed.

There are four circular steel puck holes each about 2" diameter that the hitch fits into, and locks in place in the bed, and there are rubber, or hard plastic, covers that fit over these holes when the hitch is removed. It is those covered holes that protrude from the truck bed slightly, but I can easily cut out 4 holes in a sheet of plywood where these holes are, so the plywood would fit flush on the truck bed, and block it where needed otherwise.

As I said before, I am inclined to follow NL's recommendations, as several of you have now said you were told by them to do.

Posted By: [email protected] on 10/25/16 04:03pm

Just another data point. I have the same 5th wheel setup on my 2013 F350. I just put a DeeZee bed mat over the 5th wheel pucks. I don't see any issues with doing that - the pucks are so close to flush that the bed mat hides any irregularity. Camper should slide right in on the mat. The bed already has a corrugated design and the 5th wheel hitch holes and plugs aren't much different in height from the ripples in the bed design.

Shawn
2013 Ford F350 6.7 CCLB Ruby Red SRW, sway bar, Bilsteins, etc
2007 Cyclone toyhauler, 18,000 GVWR
Northstar Igloo 9.5
https://photos.smugmug.com/photos/i-2J3zF6J/0/M/i-2J3zF6J-M.jpg
US Army retired

Posted By: TomP40 on 10/25/16 04:39pm

Horse stall mat from Tractor Supply held my camper great in the hills of West Virginia.

2007 F-350 4X4 SB Lariat 6.0 Powerstroke, bullet proof upgrades-EGR, remote oil cooler, stand pipes &dummy plugs, blue spring, water pump, STC fitting...
1997 Lance Squire 3000-My first Truck Camper

Posted By: TxGearhead on 10/25/16 05:36pm

Same thing with my Ram.....factory prep for 5th wheel. I use a 1/2" sheet of plywood with a bed mat on that.
I do want to raise it a little. Maybe a sheet of OSB. Maybe foam. I dunno.

2018 Ram 3500 CC LB DRW 4X4 Cummins Aisin Laramie Pearl White
2018 Landmark Oshkosh
2008 Bigfoot 25C9.4
2014 NauticStar 21 ShallowBay 150HP Yamaha
2016 GoDevil 18X44 35HP Surface Drive

Posted By: Bedlam on 10/25/16 07:18pm

TomP40 wrote:

Horse stall mat from Tractor Supply held my camper great in the hills of West Virginia.

You can see how my hitch hardware sticks up more and running 3/4" thick mats allows the camper floor to clear it.

[image]

Posted By: deltabravo on 10/25/16 07:34pm

There's quite a few areas that don't have a "local Tractor Supply Store", so check the "farm and ranch" type stores for heavy duty horse stall mats.

Generally speaking, from what I have read here over the years, rubber bed mat is the best.
If additional lift is needed, to clear the cab roof, or bed rails, then a wood base of some sort is (or can be) used.

2009 Silverado 3500HD Dually, D/A, CCLB 4x4 (bought new 8/30/09)
2018 Arctic Fox 992 with an Onan 2500i "quiet" model generator

Posted By: Bob B on 10/26/16 12:31am

I used to have the horse mat under mine, but decided to remove it because of the amount of weight it added ..... That stuff is VERY heavy.

I installed this green foam which has the highest compression rating I could find without special order .... I've put quite a few miles on it with not problem so far .... If I do have problems around the edges, i will put some boards around the perimeter.

2007 Lance 1181, 2013 Chevy 3500 DRW

Posted By: a_flyfisher on 10/26/16 04:24am

Bob B wrote:

That is quite a nice looking setup you have there. I also like the idea of that piece of rubber mat - or what looks like a rubber mat - at the front end of your truck bed - to protect the front end of your camper.

Can any of those thicker, rigid rubber mats be cut with a circular or table saw?

Posted By: billyray50 on 10/26/16 06:33am

Very nice bed set up. Like the camper guides too. I used to use the foam board on top of the rubber bed mat for years though.

Posted By: covered wagon on 10/26/16 07:40am

Cannot use any foam board under a NL camper no matter how rigid. The majority of weight at the side walls of the camper causes the mid section/ bottom belly panel to push upward with the sides of the camper crushing the foam downward.

This problem is worse as you center the camper in the truck bed, since this places the camper side walls over a low point in the truck bed corrugation. Causing little or no support to where needed, it distorts the campers fiberglass belly.

I've experienced this with my NL so I always use the plywood and rubber matt. No rigid foam.

I saw an old Big Foot camper yesterday sitting on 2X12's in the bed. They had the 2X12's sticking all the way out to support the extra 2 feet of camper.

* This post was last edited 10/26/16 08:01am by covered wagon *

Posted By: bigfootford on 10/26/16 10:35am

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

2000 2500 9.6 Bigfoot,94 F250, Vision 19.5, Mich 245/70XDS2's, Bilstein shocks, air bags/pump, EU2000, PD 9260,Lifeline 100ah, 200W. solar, Morningstar Sunsaver 15A/ display panel, Trimetric, Delorme/laptop, Holux gps rec,led lights, Wave-3 heat.

Posted By: adamis on 10/26/16 10:47am

As a fellow fiberglass camper owner with a Bigfoot 2500 I sit on the fence with this one. I needed to raise my camper nearly 4" to clear the cab of the truck (98 F350). I went with the 2'x2'x1" pink foam insulating squares at my local builder supply. I glued 4 sets of 3 boards stacked on top of each other to give me 3" of rise and then added a 1/2" truck bed mat between the foam and the bed and then another 1/2" truck bed mat between the camper and the foam. The result is 4" of lift for fairly minimal weight and it has been solid for several thousands miles so far. What I like most about the 2'x2' squares I used is that when I take the camper off of the bed, the mats and squares all fit nicely into the camper without too much hassle.

The only compression observed is from the foam setting into the ridges in the bed of the truck (prior to having the rubber mat under it). The rubber mats were not critical but they did help to prevent the camper from sliding around when going on some dirt roads or steep inclines. As someone previously mentioned, if you get the right foam with the right PSI it will support the weight without issues.

Since Northern Light has given their direction I guess you should stick to it though I wonder if that is their "default" answer to avoid situations where someone gets the wrong foam with low PSI ratings.

1999 F350 Dually with 7.3 Diesel
2000 Bigfoot 10.6 Camper

Posted By: JumboJet on 10/26/16 12:32pm

I use a DuaLLiner in my RAM 3500 that has the center hole and 4 holes for a Reese 5th Wheel hitch or Gooseneck ball.

DualLiner Rubber mat with sidewall and tailgate protection.

I carry a heavy Lance 1050S and have had no issues for thousands of miles. Even went airborne once on I-35 near Dallas, TX.

Posted By: TxGearhead on 10/26/16 02:01pm

Hmmm...guess I won't put foam under the Bigfoot. I'm just being lazy anyway. I have a roll-up bed cover. The sides with the Velcro stand about 1.5" above the bed rail. I would just as soon leave them on, but it's only 4 bolts per side to remove them.

Posted By: Bob B on 10/26/16 04:40pm

Don't want to hijack the threat, but the increase in the rail height has been my dilemma when looking at the roll up covers..... I spent some time searching for one that didn't give much rise, but got sidetracked.
I think I will start another thread about this.

Posted By: youngm357 on 10/26/16 06:39pm

Used the same two layers of pink rigid foam from HD for years. Only regret was not buying blue at Lowes.

Posted By: covered wagon on 10/27/16 07:34am

bigfootford wrote:

Nice Post..... and solid advice. [emoticon]

Posted By: adamis on 10/27/16 10:02am

covered wagon wrote:

bigfootford wrote:

Nice Post..... and solid advice. [emoticon]

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.

Posted By: SP on 10/27/16 11:03am

Ive used a rubber mat under my camper since 03. I got a new Chevy 3500 in 2010 and found that the camper would kiss the side rails when lowered to the truck. Using advice found here, i went to a box store and bought a 1" and 3/4 ' pc of foam siding(4x8).
turns out the 1" was a bit to high for my liking and the 3/4" was just right. Replaced after a couple of years. Works great.
oh, it sits on top of the rubber mat. Might defeat the non skid purpose of the rubber mat....but, 6 years in, no problem.

See you out there,

SP, MP,& Ollie
Lance 1071 ">

Posted By: bigfootford on 10/27/16 03:12pm

adamis wrote:

covered wagon wrote:

bigfootford wrote:

Nice Post..... and solid advice. [emoticon]

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...

[image]

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

* This post was edited 10/27/16 03:19pm by bigfootford *

Posted By: covered wagon on 10/27/16 07:15pm

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.

Posted By: adamis on 10/27/16 08:29pm

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.

Posted By: bigfootford on 10/27/16 08:45pm

adamis wrote:

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

Posted By: HMS Beagle on 10/28/16 09:48am

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.

Bigfoot 10.4E, 2015 F350 6.7L DRW 2WD, Autoflex Ultra Air Ride rear suspension, Hellwig Bigwig sway bars front and rear

Posted By: bigfootford on 10/28/16 10:07am

HMS Beagle wrote:

I 100% confirm and agree...

No foam between the camper and bed.

Jim

Posted By: bigfootford on 10/28/16 10:08am

bigfootford wrote:

HMS Beagle wrote:

I 100% confirm and agree...

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

Jim

Posted By: a_flyfisher on 10/29/16 03:10am

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.)

Posted By: TxGearhead on 10/29/16 06:25am

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.

Posted By: HMS Beagle on 10/29/16 10:22am

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.

[image]

Posted By: bigfootford on 10/29/16 10:26am

a_flyfisher wrote:

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

Posted By: bigfootford on 10/29/16 11:09am

HMS Beagle wrote:

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

Posted By: HMS Beagle on 10/29/16 12:02pm

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.

Posted By: TxGearhead on 11/05/16 08:12am

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....

Posted By: HMS Beagle on 11/05/16 09:52am

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.

Posted By: bigfootford on 11/05/16 10:55am

HMS Beagle wrote:

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

Posted By: TxGearhead on 11/05/16 01:58pm

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

Posted By: dunegoon1 on 11/05/16 08:23pm

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.

Posted By: TxGearhead on 11/06/16 06:29am

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?

Posted By: GoinThisAway on 11/06/16 06:46am

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.

2008 Dodge 3500 DRW 4x4
2008 Bigfoot 25C10.4
Torklift/Fastguns/Hellwig/StableLoads

Posted By: HMS Beagle on 11/06/16 09:35am

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.

Posted By: TxGearhead on 11/14/16 09:02pm

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.

Posted By: bigfootford on 11/15/16 09:50am

TxGearhead wrote:

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

Posted By: TxGearhead on 11/15/16 11:40am

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

Posted By: bigfootford on 11/15/16 12:10pm

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

Posted By: TxGearhead on 11/16/16 07:00am

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.

Posted By: capeman on 11/20/16 02:57pm

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

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