Roofs buckle because either the roofing underlayment has wrinkled or the wood deck itself has shifted for some reason.
Roof plywood buckling.
If the wood structural panels are tightly butted there is no room for expansion and buckling can occur.
This happens most often in hot and humid climates.
Plywood and oriented strand board osb like all wood products will expand or shrink slightly with changes in moisture content.
When plywood or osb sheathing picks up moisture it expands.
Occasionally the buckling is caused by poor workmanship wrong materials or possibly by a problem with the structure itself.
Plywood and osb roof sheathing are the most popular roof sheathing materials in the u s.
Ripples or waves on the roof surface are a sure sign that the shingles or decking has probably buckled.
If the adhesive side is not laid properly and not applied flat it will surely show its buckling through the roof shingles.
Less likely as a cause of a buckled roof is poor attic ventilation.
But they must be installed correctly.
However warped plywood sheathing means the entire roof has to be replaced immediately or it may collapse.
That can mean costly time consuming callbacks.
Such buckling may occur between supports or between nails along supports.
Your builder is responsible for providing adequate soffit ventilation.
Call your builder and have him fix the buckled plywood.
When these boards are not properly fastened and nailed to the framing they can buckle as well.
However a more pronounced buckling in a line running up the roof like in the photo above is caused by buckling of the edges of the plywood or osb roof sheathing due to water intrusion or extremely high humidity in the attic.
On occasion poor attic ventilation can cause the sheathing to become warped from underneath.
For a good reason.
Improper installation of roof sheathing panels can result in warping or buckling of asphalt shingles.
They are easy to work with readily available and perform the job well.
Buckling of wood structural panel sheathing such as plywood or oriented strand board osb occasionally results when increased moisture conditions cause the wood to expand.
The most common cause appears to be movement in the roof sheathing with changes in moisture levels.
These ventilating systems work in conjunction with adequate soffit ventilation.
Your roof decking is the plywood sheets that cover your home.
