This often occurs in the middle of the shingle tab.
Roof bowing in the middle.
Roof lines should be arrow straight.
One of the most common causes of roof issues are problems related to the rafters or trusses.
They have issues for a wide variety of reason including damage from wind storms overloading from ice and snow leaks etc.
There are different reasons and types of curling.
Installing new rafters directly alongside the weak or damaged ones is often enough to correct this problem.
Use your string line to determine how much the roof need to go up.
Read on to find out what you can do.
If your rafters are still sagging a bit and it is causing your roof to dish out a little in the center of the roof sides add a 2x4 that goes all the way across the rafters in the center of the length of the rafters.
It might be something.
In a stick frame non truss sloped roof these issues usually cause the roof ridge to sag in the middle giving it a swayback look but can also cause one side of the roof to sag.
Curling shingles also referred to as fishmouthing is when asphalt shingles have curled on the ends and appear to be bent or twisted.
What causes a sagging roof line.
That s why most of the ridge sagging occurs in the center of the roof page top photo.
As the wall tops are pushed outwards at their center either the entire wall leans over or as the wall is held up at the building corners gable ends the wall center may break and bend over as in my photo above.
Therefore giving them a good look is critical when addressing sagging bowed or wavy roofs.
Undersized rafters also can cause sagging along the whole side or plane of a roof.
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.
It is more common than you might think for a concrete block foundation wall to bow inward and repairing the problem is a tall order even for an accomplished do it yourself homeowner.