How to reflash roof to wall with vinyl over wood siding?

I am going to have my roof replaced. On the back of the main house is a low slope roof. The wall has a vinyl siding over original wood siding, which does not seem to be in bad shape. Current flashing from roof to wall goes behind the wood siding but is worn. What is the best way to reflash it? Can I just cut the existing flashing where the roof meets the wall, add new flashing on the wood siding and put back the vinyl siding?

Yes that is the way to do it.

We do this but go all the way to the original wall, just use some pre-primed pine to shim out the recess and install the outer layer of siding. That way if/when the dormer is completely stripped, somewhere in the future, our copper flashing will not need to be replaced.

If it’s a shingle roof your best bet would be to nail down the old flashing if it can’t be removed,after roof is ripped, put ice and water guard over the old flashing and use new step flashing and when installing it make sure it goes behind the vinyl siding. Step flashing usually slides behind the siding with ease, its easy to install and is hidden. You usually don’t have to caulk anything either.

IMO it would be better to get the new flashing behind the wood siding. Not sure what kind of vinyl siding job was done on your house but its possible that the vinyl job itself isn’t totally waterproof (esp if there are windows in the area). If you had a good vinyl guy do your siding its probably waterproof however.

In between the vinyl and the wood will be just fine as long as the vinyl is installed right. You will have a hell of a time getting it behind the wood.

about this what i think is, this seems like it needs an expert care so you must go for one. DIY can save you money but it can also create mess you might end up with contacting a contractor for redo what already has been done. take your decisions wisely look for a professional help.