rooftop tent

Hi Barry, It does happen but doesn't seem to be a real issue, we simply turn the mattress on its side and air it out before we pack up. Sometimes this is not practical so then we simply fold it up as normal and it seems to dry out before use the following night. Winter and colder weather is the worse time but we never found it a real issue. We just bought a new mattress and the original foam and the cover have no evidence of mold or mildew staining, being in use over 10 years and hundreds of nights in all weather and seasonal conditions. Regards Michael

You can buy a large open mesh undermattress from boat places that ensures no condensation .

I bought one about 14 years ago and have never had condensation under my camper trailer mattress.

The stuff is black nylon and looks a bit like an old bedspring as the mesh is about 15MM high.

I anchor it at the top with a couple of self tappers partly inserted and pushed through the mesh.
The company I bought it from went out of business but you should be able to find some with a bit of effort.
Similar to this
https://www.youtube.com/watch?v=YfGquOxwAzc&ab_channel=Sailrite

Our Alu Cab has not had an issue with condensation. While most makes do including Alu Cab, the culprit is a full zip up preventing circulation. We have been in dusting snow, days of high country cloud and with two windows down 40mm - never a problem. Still have a window to go if required.

Cheers