Performance Standard: Some waviness in lap siding is to be expected because of bows in studs. Thermal expansion waves or distortions in aluminum or vinyl lap siding, sometimes called oil canning, are unacceptable if they exceed 1/8 inch in 16 inches.
Corrective Measure: The remodeler will correct any thermal expansion waves or distortions exceeding the performance standard by reinstalling or replacing siding as necessary.
Discussion: This problem is caused by the siding being nailed too tightly to the house instead of loosely “hung” in the center of the nail slots, or by not allowing adequate room for the siding to expand at the ends.