When a shed roof ties into an existing roof the new roof could be a simple lean to that covers a deck or porch or it could be the shed roof of a substantial addition.
New portico framing into existing roof.
Brace the column frame in place using l brackets and concrete screws.
First the 4x4 beams need to be cut to the size of the existing roof so the porch roof and the edge of the existing roof will be even when the job is complete.
Make a cutting on one of the sides of the horizontal roof beam on an angle.
Butt the first new truss against the old one.
After that to make it flush with the roof of the existing house cut the two outer rafters.
Using two inch by four inch studs build a frame for columns that stand from the porch floor to the soon to be built roof.
Attach the horizontal beam by using a nail gun.
Blind valleys simplify framing.
After installing the rafters we still had to extend the porch roof back over the shed roof creating a valley on either side.
The cost to build a 200 square foot covered porch ranges from 4 600 to 22 000 or 10 500 on average you can expect to pay 23 to 110 per square foot the total includes flooring steps posts railing roofing and more.
Now take the 4x4 beams and erect them to the perimeter outside the porch about four feet apart.
This includes a material cost of 11 to 70 per square foot and 12 to 40 per square foot in labor.
Tie into the end of an existing gable roof by removing existing facing boards wall siding and any other obstructions back to the first truss of the old roof.
After you shingle the roof with step flashing adressing that wall intersection tuch taarpaper under the existing tyvek and over the step falshing then re install the siding trimming it to about an inch above the shingled roof.
Tying in to an existing gable roof.
Cover the column frame with siding brick or any outdoor material that matches the exterior of your home.
Then mount new trusses on the new addition walls.
To keep the porch roof framing as simple as possible we installed a structural ridge supported by posts at each end with the common rafters landing on top of the ridge.