If it s at the edge of the roof it s usually because the foundation has given and the walls are sagging in the middle.
Roof uneven aging.
And although older roofs may continue to keep the elements out they may be more vulnerable to damage due to wear and tear over the years.
Loss of surface granules damage to the felt or composite base layer and uv damage often leads to this wavy development.
Or it could be the top sill has rotted and allowed the rafters to settle.
It also resists uneven weathering fading or chalkiness of the installed roofing system.
The shingles on your roof serve a dual purpose.
Is well suited for retrofit installations.
Signs of an aging roof can often be observed from ground level and sometimes a convenient second floor window offers a bird s eye view of the shingles.
Exposure to wind rain and sun further deteriorates the roof coverings often resulting in shingles or roof panels that appear to be peeling off of the structure.
This is because the micro climate of your building changes from roof edge to interior drain from flat expanse to spots under hvac equipment.
Even the largest single ply membrane some are custom built to your exact roof dimensions will not age uniformly.
Plus dicor epdm passes the astm 20 year accelerated aging test with no discoloration.
Lumpy bumpy or curling shingles that do not.
A roof should never sag or be uneven because it s specifically designed to bear its weight.
Roof shingles are not lying flat.
The roof has 1 layer of shingles but there are 5 places where the rafters are bowed upward and there are about 15 rafters that are sagging.
Roofs have ways of visibly showing their age.
The roof shall be viewed from a normal viewing position on the ground without magnification by reflected light.
They give the roof a finished look while forming a protective seal.
The roof sheathing shall provide an even surface free from thickness variations holes and debris that produce visible irregularities in the finished roof.
Sagging has several causes but the main one is age.
Usually when you see a roof sagging if it s at the top it s usually because the ridgebeam is too thin or the rafters are spaced too far apart.
My idea is to use my reciprocating saw to remove or use the 1st 3 feet at each end of the upward bowing rafters to add a new 2x6.
If your roof has looked smooth for years and has only developed an uneven appearance with age the change is likely due to damage instead.
Worn or deteriorated roof covering materials occasionally loosen from their fasteners and lift away from the roof which creates an uneven appearance.