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Q&A Spotlight

What Happened In This Roof?

After an unconventional spray-foam installation, stains appear on the side of the house

Spray foam gone bad: After an insulation contractor added spray foam to the roof, these stains began showing up on parts of the exterior. What's going on? Photo courtesy of James Fugate.

James Fugate’s intent was to insulate the roof of his Rochester, New York, home and make the attic part of the conditioned space. What he got instead was a mysterious brown stain that shows up on the outside of the house at certain times of the year.

The project started innocently enough. Where the roof rafters were accessible, the insulation contractor sprayed foam on the underside of the sheathing. Then he hit a snag. As Fugate explains in this recent Q&A post, on the second floor of the house is a 5-foot-high knee wall, above which is a sloped ceiling that rises to the flat ceiling below the attic. Rafters and sheathing were inaccessible in this area.

So, the contractor came up with an unusual plan. He decided to spray the foam from the outside. In order to do this, he removed shingles and sheathing above the sloped ceiling, applied the foam, and reassembled the roof.

“Now,” Fugate says, “every winter I get this brown stuff dripping down the siding of my house. It only happens when we have a thaw after a deep freeze. The dripping never occurs during warm weather. It does not happen everywhere.” There are no signs of water intrusion inside.

Getting the contractor back for remedial work is out of the question. Fugate ended up replacing the entire roof after the contractor did such a lousy job of patching the area he had removed.

What explains this mess? And what are Fugate’s best options for fixing it? Those are the issues in this Q&A Spotlight.

Is moisture condensing above the foam?

Zephyr7 believes because the foam was installed from the roof, there is now an air gap above the newly installed foam in that sloped part of the ceiling,…

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4 Comments

  1. Tyler Keniston | | #1

    GBA=Sherlock Homes

  2. Paul Eldrenkamp | | #2

    I'm skeptical that it's mostly a condensation problem. That's an awful lot of water. My hypothesis is that it's a flashing issue.

    I would get up on a ladder the next time there's a thaw after a deep freeze and observe first-hand what's going on at the drip edge.

    1. Albany Landlord | | #3

      I agree that is not likely a condensation issue due to the volume of staining. I have seen staining like that that a few times due to old integrated gutters above the roofline (Yankee Gutters) leaking and running through the soffit. Whether it is flashing, ice damming, or bad roofing I would say water is coming through the roof. The thaw after a deep freeze could also be consistent with ice damming.

  3. GBA Editor
    Rob Wotzak | | #4

    I power washed my vinyl soffits the other day and had brown liquid dripping down from a squirrel or bird nest above the perforated parts. It would be simple enough to open up those soffits (they probably just pop out by hand) and at least see where the water is running from under them before getting into any more invasive inspections.

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