The old shingled roof was just removed and new shingles installed.
Old roof new roof joined rafters bow.
Repeat the process for the joist beneath your old roof rafter.
Best solution is to tie the existing rafters at the wall plate level but this might not fit in with the floor levels and will not cure the bow in the roof just prevent future movement.
Measure the dimensions of the old rafters beneath your roofing surface.
Sagging rafters can be a serious and deadly in some cases problem in your roofing system.
Use a circular saw to cut two sets of new rafters from the same size wood by the same dimensions.
Sagging rafters can lead to serious problems with the entire roofing system.
I e the original roof was a light wood shingle roof and the new replacement roof is a concrete tile roof weighing 5 or 10 times more than the original roof.
Up from the valley center.
Is your roof in need of an upgrade.
To remove the bow will require the roof off.
Shop roofing offers from companies in your area.
Shingle the addition roof letting the new shingles fold through the valley center and onto the old roof deck by at least 1 ft.
Tie a new gable or hip roof to an existing gable or hip roof with valley rafters which perform the same function as ledgers.
Bed the end of each shingle in a 2 in wide ribbon of roofing cement placed 4 in.
If a roof has been re roofed with heavier roofing material than the original roof was engineered for.
This can cause roof caving water leakage.
If the roof was installed over another layer or several layers and it is older than 20 years chances are you need a new roof.
My roof is 15 years old.
If you notice that there is a visible dip in your roof chances are you have a problem with one or several rafters and you may soon be facing more issues like water leaks bowed out walls or your roof caving in on you.
Use your tape measure to record the distance of both rafter legs.
If you find your roof is sagging or a slight dip is visible then you are probably a victim of sagging roof rafters.
This can be a serious problem in future if not treated at the right time.
I think the roofers might have broken some of the 5 8ths inch plywood decking in places because there.
Re lay the shingles you removed from the existing roof.
It would also be very difficult to do with the roof on.
It also depends on whether the old roof was removed and you only have one layer of shingles and if it is properly ventilated.