Slightly OT: General Carpentry

if there's a drip edge available from the old roof tuck the flashing under that. depending how much overhang the roof above has and whether the gable faces incoming storm winds the water tightness needed could vary. probably this should be flashed to the top- caulking the upper edge of a flashing is asking for trouble.

Go with the kerf method, but first step flash up both sides as you shingle as per standard roofing procedure. Then bend a piece of flashing or break metal that fits in the kerf and folds down over the step flashing and run that up both sides providing a nice clean finished look and absolute leak protection. If done right I can guarantee this will not leak, ever.

Jim

For the small amount you're dealing with (8" height) rip the siding out when you strip the old roof. (You are stripping it, right?) Install new step flashing on to the studs or sheathing and then install new siding over the step flashing. Done right, watertight.

Exactly how I'd do it if it was new construction but the existing roof is staying. i could remove the 8 in or so of siding toward the front of the cabin but because the addition only spans half the depth, there's a lot more siding to remove from the rear. A profile of the existing and new looks something like this: /\ / \ / \ / \ //\ \ // \ \ // \ \ || | | || | |

You could easily use your circular saw by resting the shoe edge on the roof sheathing of the addition and the base against the T-1-11 (if you're using a saw with the blade mounted on the right you'd make your cut left to right, right to left for a left mounted blade). Set the depth of cut and have at it. This would create a cut approx. 1-1/2" above the sheathing. Cut out the narrow strip with a sawzall. Seal the cut edge with whatever finish you have on the siding. Step flashing material is very flexible so you should have no problem sliding it under the siding as you apply your shingle courses up the roof.

The problem with the kerf method you mention is that it allows for a place for water to pool. Caulking it would be fine for the short term but eventually it WILL break loose.

Scott

-- An unkind remark is like a killing frost. No matter how much it warms up later, the damage remains.