Accordingly, how do you tie an existing roof line?
The easiest way to tie in the new shingles with the old is with a cut valley (see Four Ways to Shingle a Valley). After the addition roof is framed and sheathed, snap a line on the existing roof shingles 2 in. up from the valley center, and cut through the shingles and underlayment.
Beside above, can you build a roof over an existing roof? In this case, you can build a new roof over the old – with a caveat. You must not build the new roof directly over the old. A new coat of shingles over decaying shingles will cause your roof deck to decay. The cheapest option would be to leave the old roof in place and place the new rafters over the existing roof.
Just so, how do you join two roofs?
Position the flashing between the two roof pitches. Slide the right edge of the flashing under the highest roof pitch. Place the 2-by-4-inch piece of lumber along the center of the flashing. Gently bend the flashing using the edge of the lumber until both sides of the flashing match the slope of the two roof pitches.
How do you increase the pitch by building a roof over an existing roof?
Replace any wall cladding you tore off, and install new soffit and fascia. Nail the trusses into the existing room fasteners. Once the trusses, soffit and fascia are in place, lay the roofing felt in place. Now you can begin shingling your roof, preferably with asphalt shingles.
