When tying a new roof into a old roof, some say they just nail the valley board directly over the old shingles and others say best to remove the shingles then nail down the valley board. The roof pitch is 6/12 and adding a sunroom that is 10’ x 16’ with the 10’ along ridge length (not counting the tie-in ridge of 4’6") x 18’ truss length with a 3/12 pitch.
Also I have the original truss specs. 20 PSF additional BC live load check per BOCA96. States deflection meets L/360 live and L/240 total load.
Questions: if no rain in forecast, should I remove the required shingles or just nail over existing singles. Actually I’m thinking to cut out a hole to allow ventilation from old into new?
And assuming my trusses will support the addition of the tie-in, as the sunroom walls will support the rest of the roof?