All PermaTherm's structural insulated panel products are warranted to be free from defects in materials and workmanship for a period of one year from the date of shipment. A certain amount of "waviness" or "oil canning" is inherent in any product made from sheet metal. Installation of large areas of metal panels or installation of panels to misaligned structures will cause unnatural stresses, increasing the likelihood of oil canning.
A stucco-like embossed texture in a precoated material will reduce the visual effect of oil canning. Oil canning does not affect the structural or thermal integrity of the panel.
Minor waviness of the panel does not indicate a defective panel and is not a cause for product refusal.Minor blisters can sometimes occur when the panel's exterior face is exposed to the sun. This is caused by the thermal expansion of a blowing agent, which is trapped under the panel face. This is a common phenomenon and is easily repaired and is not a cause for product refusal.
Finish panels are free of surface imperfections (dents, mars, scratches, etc.) and visible with panel in position of intended use and view under good light from intended installed distance or 8 ft., whichever is greater.