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Spray foam squirts out of house — potential water vapor access?

Nola Sweats | Posted in General Questions on

I just had my attic sprayed with open-cell spray foam as part of some energy-efficiency improvements.  (Yes, all the ductwork is in the attic, and yes, I’m monitoring humidity levels to see if I need ventilation/conditioning to keep the sheathing dry.)   Zone 2A, 0.5 lb foam.

Outside of the house, there are a few spots at the soffit where foam squirted through and expanded.  Picture some white Nerf footballs wedged behind a 6″gutter that sits under a very narrow soffit.  There were no soffit vents, so these are gaps in the soffit or fascia that were hidden by the gutter.

The extruded foam is over 20′ above ground and not easily reachable.  My question is whether there’s any risk of the weather-exposed foam wicking rainwater up into the attic, or perhaps adding to the attic moisture load as the water evaporates in the sun.  Many thanks!

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Replies

  1. Expert Member
    Dana Dorsett | | #1

    Half pound polyurethane isn't hygroscopic. While it can take on water via vapor diffusion, and can even become saturated, it doesn't wick moisture.

    Bottom line- it's not going to draw moisture into your attic.

  2. Expert Member
    Zephyr7 | | #2

    I wouldn’t worry about water wicking.

    You could probably knock the foam balls off with a long pole pruner, or a pole with a loop of wire on the end to hook the foam balls. Unless the foam leak is a pretty big area, the foam “balls” you see should be pretty easy to snap off without using much force.

    Bill

  3. Nola Sweats | | #3

    Thanks, gents, that's reassuring. I thought about throwing some actual nerf balls up there to knock them down, but that seemed likely to backfire.

    I gave away my pruner (good idea!), but I have some 6' pieces of quarter-round that I can probably use to jab at them from atop a ladder.

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