Help designing DIY camper mattress - only 5" max height available


I have a Four Wheel Popup truck camper that came with a very hard 4" foam bed and am looking to create a DIY solution that is more comfortable. I am limited to a total mattress height of 4" to 5" so I realize I will never have the proper support of a home mattress, but I need to do the best I can with this space.

I am a 5’ 9" 200lb side sleeper. Currently on the extra firm factory foam I wake up numb about every 1/2 hour and sleep poorly. My initial thought was to try the 3" dunlop latex duvet topper on clearance from member company on top of 1.5" to 2" of 30ILD HR 2.4 polyfoam base. Any thoughts or other suggestions?

Thanks in advance.

I would probably do a cheap foam setup 3" of HD36-HQ from FBM topped with 2" of your choice of 5# memory foam. 3" of a firm latex with 2" of a medium might not be too bad.

Hi SeatleDucks,

Because this is what I would call an “application critical” project and because it will involve compromises between pressure relief and support (your layers need to be firm enough to avoid bottoming out) my first suggestion would be to first do some local testing on various layers that would give you a much better sense of how a particular layering combination would feel to you. Fortunately there are several good sources in the Seattle list in post #2 here. While several of these would be a good place to test latex, may be the best bet because they carry foams of all types (including latex and high quality polyurethane foam and what they don’t have they will source for you) and Earl knows his stuff.

If you did go with an online source (and is a very good one and has great prices for their toppers) … your idea about 3" of dunlop with a couple of inches of HR polyfoam under it would likely work well except I would probably increase the firmness of the polyfoam a bit to the mid 30’s to make sure you weren’t bottoming out. A single layer of 4-5" of Dunlop (there are full cores that are 5.5" if you can get away with this) would also work well in the right ILD (probably mid 20’s) but this is harder to find in layers of this specific thickness. Dunlop would be a good choice in this application IMO because it has a higher sag factor than talalay which allows you to use softer ILD’s with less risk.

I would definitely avoid memory foam in a mattress this thin because you will “go through it” too easily and this would leave you on top of the thin firm layer below it. You would need a thicker layer of polyfoam under it for memory foam to work well and you don’t have the room.

I would also personally avoid ordering any application critical foam of any kind from FBM because you never know what you will receive. The two most important “specs” of a thin mattress like you are suggesting are ILD (or IFD) and compression modulus (AKA sag factor or support factor which is basically the speed at which a foam gets firmer with deeper compression). With a layer this thin you want a high sag factor to avoid bottoming out. All the FBM polyfoam lists a support factor of 1.9 which is typical of conventional foam which I would avoid. Even if this is wrong and their higher density foam has the wrong specs listed … I personally wouldn’t take the chance of ordering anything important from them.

Some of the better sources are in post #4 here if the local sources (which would allow you to test the exact combination you actually ended up ordering) don’t carry what you want or if the cost was too high compared to an online source.

Hope this helps


Phoenix, thank you for the guidance, much appreciated.