Thread: Urethane insulation on exterior of the foundation

Hi guys,

Is it a normal practice to insulate the exterior of a foundation with Urethane spray foam ?

Does it need to protected or covered somehow (below ground or over ground) ?

Could the humidity in the ground damage the insulation in the long term ?

Thank you for your help

Originally Posted by Christian Tag

Hi guys,

Is it a normal practice to insulate the exterior of a foundation with Urethane spray foam ?

Does it need to protected or covered somehow (below ground or over ground) ?

Could the humidity in the ground damage the insulation in the long term ?

Thank you for your help

I do not believe that it is rated for UV exposure. When I see it exposed (only at small areas, never like that) it tends to deteriorate.

It really depends on the specific material that was applied.

Originally Posted by Jack Feldmann

It really depends on the specific material that was applied.

Jack,

I agree that it depends on the specific material applied, however, I have not seen any spray foam insulation which is rated for prolonged exposure to sunlight ... not yet anyway.

A give-a-way that the material in the photo is not approved for prolonged exposure to sunlight is that the surface has 'burned' and turned that color, and is also now likely quite hard. Even the spray foam used on roofs is not rated for exposure to sunlight, it is supposed to be protected almost immediately after spraying.

Have you seen some which was rated for prolonged exposure to sunlight?

It will over time loose insulative value. There are protective coatings that can be applied. I believe latex paint will suffice. Some foam applications can have UV protection in the mix, but this doesn't appear to be the case.

Jerry,
I agree that its likely not a material that's approved for exposed use, but I don't keep up with all the latest greatest stuff, and have no idea what was applied to that house.

Thank you for your help,

One more tricky question, there is a porch all around the house which prevent the sunlight deteriorating the insulation, would you still guys still recommend something ?

In my own home which has spray insulation on the open underside of the floors which do not receive direct sunlight are yellowing, so I would say yes.

So you don't have termites there? It is not allowed at/below grade here.

Originally Posted by Christian Tag

One more tricky question, there is a porch all around the house which prevent the sunlight deteriorating the insulation, would you still guys still recommend something ?

In addition to what Jim said, if it was not pitch dark under there (and it does not look like it is), then it needs protection from UV, both direct and reflected sunlight.

Here in MN it needs to be protected from UV and pest. Mice will burrow into it. Usually it gets covered with a concrete skim coat. But, they're also starting to glue colored vinyl sheets over it.

Termites are not common in Montreal. But they do exist in isolated areas where they have arrived in pallets or crates. Or so I have read, having no personal knowledge of Quebecois termites myself.

As usual, if it looks wrong, it probably is. It is amateur work and I would report it.