My asphalt shingle roof (approximately 20 years old) leaks. This is the roof over the first floor that covers the kitchen, BR closet and bathroon. I have had leaks into all three rooms. I replaced the black felt and 27 feet of shingles (linear) from the side of the second floor wall outward about three feet. I installed new flashing up under the old flashing and re-nailed it. I've used black roofing caulk as well as elastomeric caulk and have slowed down the leaks but not stopped them.
Went back out two days ago and noticed the bottom corner of the windows were rotted. Since it was about to rain, I caulked the corners and the area under the windows. That almost stopped the bathroom leaks.
My question is, is there a temporary fix I can apply over the shingles and the exposed flashing (6 inches) to act as a water barrier until next spring?
I've looked into Koolseal's elastomeric roof coating but they say it does not work for asphalt shingles.
Any suggestions? Thanks much.