Hello all,

I am looking for some advice on tying a new porch roof into the existing roof. The porch extends 8′ out from the house, and is to have a shed roof with 4 in 12 pitch. Existing roof is 9 in 12. I plan to lay a “ledger-don’t know the correct term” across the existing roof for the new rafters to bear on. My questions- Do I need to remove the shingles before fastening this board? How do I determine rafter lengths and angle for plumb cut on new rafter?  And, finally, method for weaving new shingles into old without leaks? Thanks in advance for any assistance you can provide.

Scott