We moved into our house about five years ago and did not notice the attic mold. Shame on us. Our attic has mold on all for sides of the hip roof. The worst of course is on the north side of the attic. I would guess mold covers 60% of the attic sheathing. However, no mold has grown on the supporting joists that are in contact with the sheathing. Since I was not the original owner, I can only guess what caused the mold. We know the previous owners overhauled both upstairs bathrooms and properly vented the shower/bathroom fans with PVC running through the attic and to the outside of the roof. The problem is, itÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s quite possible that for many years prior, the bathrooms either had no fans to remove moisture, or they did, but they may have been vented to the attic. Clearly, moisture has made it into the attic and caused lots of mold.
Our roof has a power ventilated fan in the upper center. It also has three plastic roof vents near the top of the roof. All vents on are the west side of the roof. The soffits have a total twelve vents to supplying air into the attic and exiting through power vent/plastic vents. The attic floor is about 800 sq. ft. and this is a two story house. I believe the power ventilated fan was installed after the house was built.
I believe the source of moisture has been solved with the proper venting of the showers, but IÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢m not 100% sure. My attic floor has no vapor barrier, but has about 8 inches of blown-in insulation on avg. Was it unusual to have a home built without a vapor barrier during the 80ÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s? I have no clue why anyone would do that. I suppose moisture could be making itÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s way through the attic floor. Since I have noticed the mold (about four years ago) I have installed a humidistat on the power attic vent so I can run the fan in the winter as well. It appears the mold growth has slowed or stopped, but itÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s still there.
My house was built in 1982 and most likely has the original roof. While the shingles still have some life in them, I will need a new roof soon. Does it make more sense to just have the singles and roof sheathing replaced instead of having the mold professionally removed? IÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢m not sure how much added cost the sheathing replacement would entail, but the remaining mold would definitely be gone if I went this route. My concern is it could return. I suppose I could just keep checking the new roof sheathing to see if mold reappears. If I caught it early this time, I could have a mold remediation company solve the problem and it wouldnÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢t be too costly
I live in Northern Illinois.
Thanks in advance for your feedback.