This video explains how to properly use flex seal to seal a roof leak in the corner.
How to repair a roof leak in the winter.
Add 8 inches for the thickness of the wall studs plus drywall plus exterior siding.
Step 5 use a caulking gun to apply caulk to seal any holes that appear in the roof.
To stop the leak use a long handled roof rake to remove snow from your roof or blow cold air onto the area of the roof that is leaking in your attic using a box fan.
There should be an additional 4 feet of tarp on every side.
Run water over the low side of the penetration for several minutes while the helper watches for any water droplets.
Perhaps placing tube on furnace duct so air heats pre cut tube inside of home then climb up ladder and seal area keeping the sealant warm and easily caulk able.
Use enough water to mimic heavy rains.
You should be using the repair fiber in order to achieve a long lasting.
Let the wet areas dry and then apply the patch to the underside of the roof with a putty knife.
This will freeze the leaking water in place but you ll still need to deal with the ice dam or it will melt and start leaking again.
Isolate areas when you run the hose.
Measure from the inside wall to the point of the leak.
Create an anchor board by rolling the tarp s peak end with a 2 x 4 inch board and nailing the tarp to your board with your 3 inch nails.
Start low soaking the area just above where the leak appears in the house.
In the wintertime ice has no problem building up under the roof membrane shingles and gutters.
For example soak the downhill side of a chimney first then each side then the top on both sides.
Use enough of the roof patch to liberally cover the leaky area.
If a leak is difficult to find enlist a helper and go up on the roof with a garden hose.
First look on the inside where the leak is.
The ice builds back up when it reaches the wall line where the house is heated and it creates an interior drip.
Sealing the shingle to the object can be accomlished with a roofing sealant available at menards lowes etc.
Proper ventilation rain and ice shields along with installing a drip edge will help prevent this problem.
Then add in the width of the overhang.