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
