DIY Memory Foam RTT Mattress


This is a very quick, dirty, and simple DIY on how to make a new, hopefully, more comfortable mattress for your roof top tent.

First of all, our RTT originally came with a very nice 3″ high density foam mattress with cover. This mattress served us very well for the first year of its life. We could have very easily just replaced it with another sheet of 3″ high density upholstery foam. Problem was I felt there were a few design flaws with that and did not want to have to keep replacing the mattress each year. One of the main issues is right where the RTT folds, it compress the foam mattress for the entire time the tent stays folded. This quickly puts extra wear on the mattress. This also happens to be the exact spot where my hip goes. Being a side sleeper that can get mighty uncomfortable.

So where does that leave us now? I wanted to find some other materials that would hold up to the stress of being constantly compressed while stored and also work well as a mattress. What we decided on was a top layer of 2″ 4lb density memory foam. The middle layer will be a 1/2″ layer of 2lb polyethylene closed cell foam.  This is the same stuff that most foam camping pads are made of. Finally the bottom layer will be a 1/4″ layer of 4lb density polyethylene foam. Just in case the middle layer isn’t enough.  All this adds up to a total mattress height of 2.75″ and will fit perfectly in our original mattress cover.


All material was ordered from

  • 1 x California King 72″x84″ 4lb ViscoPLUSH Memory Foam mattress topper – Blue
  • 1x 8′ linear feet of 2lb density 1/2″ thick Polyethylene Foam Roll
  • 1x 8′ linear feet of 4lb density 1/4″ thick Polyethylene Foam Roll


We used our old foam mattress as a template to mark and then cut all of the components of our new mattress. Cutting the different foams was made relative easy by a good utility knife. Once everything was cut to size. We simply slipped the cover over the new foam and were done!

First impressions, while testing it on hard concrete, were that it’s different than the original but much better. It’s different because its not quite as plush as the old foam. The Polyethylene is much more dense than the old foam and will not allow you to sink through to the concrete. However the memory foam compresses a little  easier than the original foam. If I were to add anything I might add a 1″ layer of regular high density foam under the memory foam. and discard the 1/4″ of 4lb polyethylene foam. I would have the 2″ memory foam and 1″ of regular foam in the mattress cover and then the 1/2″ of 2lb polyethylene under the mattress.

Our first trip with the new mattress will be Overland Expo East. We’ll have a solid three nights of sleeping on the mattress. This should give us a good idea of how it compares and any areas we could improve with it. I hope to keep everyone updated on this as time goes with my opinions. If you’ll be at Overland Expo East feel free to find us, say hi, check out the new trailer, and new RTT mattress.



The first trip with the new RTT mattress was a huge success. We used our trailer and RTT for the three nights during Overland Expo East. I have to say the normal aches and pains we were waking up with before were completely gone. I really attribute this to the layers of Polyethylene foam that were used on the bottom. The most common pains we had were outer hip pain since we are side sleepers. Our hips would sink through the regular foam over the duration of the night and rest against the hard floor of the RTT. The 1/2″ layer of 2lb Polyethylene foam alone should be sufficient enough to keep this from happening. I would  recommend to anyone, even purchasing an RTT new, to think about adding the layer of Polyethylene foam. I haven’t yet decided if I am going to add the 1″ layer of regular foam or not. We have two more trips coming up in the near future and they will give us the chance to evaluate the mattress even further. Should be another 4-6 nights of use for the new mattress before Thanksgiving is here.


3 thoughts on “DIY Memory Foam RTT Mattress

  • Thanks, this is exactly what I was looking for. Side sleeper in our Baroud Horizon Vision and as wonderful as it is and it is… I need exactly that extra 1/2″ under the Baroud mattress. Thanks

    • Yep, that closed cell polyethylene 2lb. foam layer really makes all the difference. We actually put a 1″ layer in our new HEO T5 Trailer Tent under the mattress. Probably overkill. Don’t really need more than 1/2-3/4 inch.

      • Did you have an article where you discussed the blanket you use? Or perhaps that was another blog somewhere in what is left of my memory. Who knew that Bayfield on Lake Superior might be cold in August? Kayaking the caves should be fun though

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