Need help with a mold issue.
Hello All. I am beside myself. I will try to explain this so it is understandable. We just did a complete remodel down to studs on our home. We did not re-do the metal roof because it was just done by the previous owner. The old owners had the new metal roof installed, and they put the new roof on top of an old existing roof that had not been removed. It is almost like they built a whole roof with 2-4’s and all on top of the old roof. Pictures provided.
There are still air vents, the little round holes with screens over them that go all the way around the house for the old roof to vent.
We had the entire house sprayed with closed-cell foam. The walls and ceiling were sprayed with the closed-cell foam from inside.
Recently, mold has shown up, and I cannot figure out why. Is it because of the old window that needs replacing (which it does not seem to be the case) or is it because of the new roof being put directly on top of the old roof that created a gap there and that the vents need to be sealed off now because of the spray foam, or do these vents need to open and I need to open them more to get more ventalation in the inbetween area that now exist because of the way they put the new roof right on top of the old roof. I have found that the mold is concentrated just on the top header board that runs the length of the top of the wall, if that makes sense. I have not found mold down in the walls yet, this is why I do not think it is the actual old window, but I am not sure. I cannot wrap my mind around how a new roof is installed over an old one.. Please, any help. I am adding pictures to show the mold concentration area, the gap area from the old roof to the new roof, and the ventilation holes.
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When I google "how much open area should a soffit vent be?" this is the response I get: "Soffit vents should provide a minimum of 1 square foot of net free area (the actual open area for airflow) for every 150 square feet of attic space. This ventilation is crucial for controlling moisture and preventing heat buildup in the attic."
Are you sure the mold is just now showing up?
You have soffit vents but do you have a ridge vent on both the old and new roofs? Can you tell if the old and new roofs are both venting adequately at the ridge?
Is the new roof vented all the way from the soffit to the ridge (not the vents in the photo but a vent between the two roofs)?
Where was the spray foam added in the ceiling/roof assembly? You say it was added inside, but where specifically? Were the vent holes covered up by the spray foam? Was the spray foam was applied to the top of your ceiling inside your attic to maintain your vented roof or was the spray foam added to the underside of the old roof in order to create an unvented roof?
Why is there spray foam on the ceiling on the outside of your house as seen in the photo (I'm assuming this is outside with the clapboard siding)?
Is there mold in the attic? Is the mold we see above the window the top plate to the wall or just the header for the window?
Thank you. That is a lot. I will have to figure all this out. It may take me some time.
Those holes are only slightly better than nothing. Code MINIMUM is one square foot of "net free area" (NFA, which roof and soffit vents are rated for) per 150 square feet of attic floor space. You ideally want both soffit AND ridge vents too, so that you get convection airflow from soffit to ridge.
It IS possible to build an unvented roof, a so-called "hot roof", but usually you need to use closed cell spray foam applied DIRECTLY to the underside of the roof sheathing -- it has to be fully adhered to the underside of the roof, and it has to be thick enough for your climate zone. Did you insulat the underside of the roof like that over the entire area of the structure that is currently inadequately vented? Note that you can get round retrofit soffit vents that can be installed with a hole saw that might be a good way to add some venting instead of those small drilled holes. All the box stores have the round vents.
The pics look like the underside of the header over the window might show some rot, which is likely an issue with the window flashing or possible roof above. Water running down into the wall behind the siding can do that, as can excessive moisture WITHIN the wall, which usually gets inside walls in heating dominated climates when the walls aren't insulated and sealed correctly. The other area appears to be the top plate of the wall. That looks like either very bad mold or rot. I would suspect moisture condensing in the roof ran down and kept the top plate wet, or ice dams caused water to back up and get to the top plate. It's difficult to know for sure how the moisture got in there without more info.
Can you detail your wall assembly some more in that problem area? Exactly how was the insulation done, etc.? More pics of the roof assembly would be helpful too, especially looking up at the edge so we can see how the new roof was built over the old one.
Bill
Ok, I will have to figure all of these questions out. It may take me some time.