The worst area is over a full bathroom that doesnt have an exhaust fan or window and theres an attic access hole directly outside the bathroom door.
Roof sheathing buckling.
They are easy to work with readily available and perform the job well.
When plywood or osb sheathing picks up moisture it expands.
This then telegraphs to the shingles above.
For other possible causes.
Asphalt shingles sometimes buckle slightly and in an irregular pattern due to moisture in a the materials of a new roofing system.
But they must be installed correctly.
Under your shingles there is a layer called the roof sheathing.
Plywood and oriented strand board osb like all wood products will expand or shrink slightly with changes in moisture content.
A broken sagging rafter will also cause a dip in the roof s surface.
But the moisture evaporates as the materials reach equilibrium with the the surrounding air and the shingles settle back down flat.
Spacing and significant changes in moisture.
But if your roof surface is sagging between trusses lack of h clips is only one potential culprit.
This sheathing is generally made from plywood or a similar material.
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If the sheathing is properly gapped then the gaps can close causing the shingles spanning the gap to buckle.
Also h clips reduce any buckling of those edges over time so they are a good idea even if not always required.
Any ideas what might cause severe buckling of roof sheathing.
The boards dont appear to have come loose at the nails but instead have cuped badly 1 1 2 2 in places.
The nails slip out of the sheathing and create small visible bumps on the surface of your roof.
Buckling shingles can sometimes be traced back to mistakes made during roof installation even though the buckling may not show up for a year or two after you get a new roof.
Apa recommends a 1 8 inch space between panel edge and end joints.
Visit our blog post why is my roof sheathing sagging between the trusses.
That can mean costly time consuming callbacks.
For a good reason.
Buckling can occur if the wrong type of nails were used to connect the sheathing to the rafters.
This house dates back to the 60 s with 3 4 1x8 pine decking.
If the sheathing is not gapped the sheathing itself may buckle especially with thin sheathing 24 in.
If the wood structural panels are tightly butted there is no room for expansion and buckling can occur.
Diagnosing other roof problems.
Plywood and osb roof sheathing are the most popular roof sheathing materials in the u s.
