Patrick Knight

I am attaching a patio roof to my existing home roof leaving room for expansion at a later date. ( increase the slab and roof in length) My question is in the detail of the intersection of the old and new roof. What is the suggested and or proper installation of flashing and roofing at this detail?

Thanks for any help,

Patrick

glennjanie

Welcome Patrick:
Your word picture is of a gable roof being extended or lenghthened. If that is the case, you will need beams on the front and back sides to support the roof trusses at the same height as the existing ones. Then use the same thickness roof decking, use 15lb felt underlayment and weave the new shingles into the existing ones. Usually you can pull out every other piece that comes to the end of the existing roof, which will be cut back 6" or more and we'll say the alternate existing shingles are full length.
By weaving the shingles to match the existing ones and a flush roof deck there will not be any need for any flashing.
Glenn

Patrick Knight

Hey Glenn,
Thanks for the information. I was thinking of a shed roof extending (using rafters to a post and beam construction that extends to the edge of the patio.
It sounds like I can use the same roof intersection detail that you described in your reply.
Thanks again
Patrick