pros and cons?

dos and donts?

anyone?

Condensation can be a problem for insulation, especially in vans and buses with metal body work.

The moisture in the air inside a house truck will condense on any cold surface that it contacts as it works the way through the layers of your walls/ceiling, and often this condensation will happen between your insulation and the outer skin of the bus or van, making the insulation damp and reducing it’s effectiveness.

There are several ways to avoid this:
- add an airtight layer (building wrap or similar) inside the insulation but underneath you internal cladding. This stops the moist air getting to the cold surfaces outside the insulation,
- or use use insulation that either doesn’t absorb moisture like extruded polystyrene (blue or pink building foam) or can absorb and release moisture like wool does.

Expanded polystyrene (the white beady stuff) does absorb moisture, just fairly slowly, but can absorb a lot over time and get very heavy. In a house truck situation painting white polystyrene with water based external house paint will pretty much stop the moisture absorption (but it doesn’t work for spa covers as I am finding out first hand!)

Polyester is good insulation, but moisture can ‘wick’ into it and it can take a while to dry out. The good thing about polyester insulation is that you can staple or fix it in the cavities in your walls and know it will stay there. Fibreglass probably wouldn’t.

Fiberglass based insulation is the worst, as moisture tends to dissolve the glue that holds it in a fluffy state, and it sags and compresses when it gets damp (not to mention the itchiness issue when installing it.

Hope that helps a bit.