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Quote: Originally posted by Mod-con on 05/5/2015A thermal membrane? Condensation will only form when cold air meets a warm surface and vise-versa. When the warm moist air meets a colder surface, the warm moist air condenses below its dew point and depending on the relation between the air temperature and the air humidity present, the moisture condenses. The conditions that this can happen can vary of course. That's when you get dampness in a folding camper. There is a relationship between the different temperatures and humidities at which dew point occurs. Water vapour from breath and skin will condense especially at night on any surface that is below its dew point. The silver backing and space between the outer and inner layers of insulated radiator foil, stops the heat from passing through it. It stops heat by reducing, conduction, convection and radiation. That's how the foil works and is designed to so, with the little air pockets between the foil layers. It will keep the moist warm air from either cooking or body heat from coming into contact with the colder wood or (steel frame), which I think could be more the culprit. Steel is a better conductor of heat and cold. That's why a tent needs a inner tent to trap the warm moist air inside, from condensing on the colder inner surfaces. The pvc windows are cold at night, and they will show condensation too if conditions are right.

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The slats may work because they allow some air to circulate between them. The plastic bed sheet can act like a vapour barrier of course, but if it too gets cold enough to satisfy the humidity of the air inside the unit, then condensation will form. The silver foil insulation with the sealed air pockets between, must be placed directly onto the wood surface of the bed on the inside, just below the mattress. Any metal that is exposed to outside air must not come into contact with the mattress especially if it's very cold at night. The plastic sheet acts like a vapour barrier and should be placed between the insulated foil and the underside of the mattress. Correctly it should be pulled over the top of the mattress during long term storage, or if the canvas is wet when its being dropped down. It protects against dampness on the bed. On my folding camper, I have ensured that the insulated foil turns up from the wooden base, all the way around the top of the exposed metal base-frame, that encloses each bed. Contact of parts between the inside and outside walls of every camper should normally have a metal break of non-conductive. This can been seen around the door and top edges of any folding camper, and is normally made of plastic.     

Post last edited on 05/05/2015 18:11:56

Post last edited on 05/05/2015 19:11:51

Post last edited on 05/05/2015 19:43:59

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