Hi,
I think the best solution is to use the Great Stuff foam - it is a VERY good adhesive and as it expands a bit behind the Polyiso, it fills the space with foam that prevent water vapor from getting behind the Polyiso and condensing. You should also be a bead of foam around the full periphery of each Polyiso panel to prevent water vapor from getting behind the panel.
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This may be a little overkill, but you get the idea.
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You do have to use spring sticks to brace the panels in place until they cure, but this is pretty easy.
Most people find it worthwhile to get one of the Great Stuff Pro applicators and use the Great Stuff Pro foam cans - makes applying the foam a lot easier.
If a little water vapor gets through in limited areas its not the end of the world - insulations like Thinsulate allow very easy penetration of water vapor through the insulation and condensation on the van skin, and there are very very few reports of this causing a problem.
Gary
I think the best solution is to use the Great Stuff foam - it is a VERY good adhesive and as it expands a bit behind the Polyiso, it fills the space with foam that prevent water vapor from getting behind the Polyiso and condensing. You should also be a bead of foam around the full periphery of each Polyiso panel to prevent water vapor from getting behind the panel.
This may be a little overkill, but you get the idea.
You do have to use spring sticks to brace the panels in place until they cure, but this is pretty easy.
Most people find it worthwhile to get one of the Great Stuff Pro applicators and use the Great Stuff Pro foam cans - makes applying the foam a lot easier.
If a little water vapor gets through in limited areas its not the end of the world - insulations like Thinsulate allow very easy penetration of water vapor through the insulation and condensation on the van skin, and there are very very few reports of this causing a problem.
Gary
