Insulation

[JackE]

Hello

I was wondering if anyone has ever used this for insulation White Dacron/Polyester Insulation http://www.harrisonstrimsupplies.co.uk/ ... -116-p.asp

I was thinking of using some foil backed bubble wrap and then put in some of the Polyester, but wondered if this will soak up water like fibre glass?

An alternative would be to use the foil backed bubble wrap then some pipe insulation as this is closed cell I don't think this would hold water?

Any tips would be appreciated.

Many thanks

Jack

[clift_d]

Fibrous insulation is always open cell, and so can hold water inside. You need either a closed cell insulation, or something open cell that's been encapsulated in plastic, preferably not a mixture of types.

The problem is your van contains warm moist / humid air. This humidity in the air will condense out when the air gets cold enough. The air at the inner face of your insulation is warm enough to keep the humidity in the air. The outer skin of your van is cold enough for the humidity to condense on. Somewhere in between these two surfaces the temperature drops to the point at which the humidity in the air would start to condense - this is called the dew point.

If you use a closed cell insulation, or open cell sealed in plastic, then you still get the change in temperature through the insulation from inside to out, but the moisture in the air can not get past the inner surface and so never reaches the a temperature low enough for it to condense.

If you use open cell insulation then the moist air can infiltrate the insulation and any moisture that gets close enough to the cold outside will condense inside the insulation, where it collects and can lead to corrosion.

Something like a PVC Nitrile sheet foam insulation would be a good choice as it is closed cell, flexible and can be fire retardant.

[JackE]

Many thanks for this. I will also closed cell produce and then use some plastic sheeting behind the outer trim to stop water vapor getting into the cavity. Thanks again