欧美日韩国产精品免费观看国产久久亚洲不卡,，日韩无码国产AV日本在线一区二区,，免费毛片二区三区久久久五月综合激情影院

Synthetic underlayment is a roofing accessory created by weaving/spinning together polypropylene or polyethylene and a polymer to form an all-over protective barrier to put between the roofing material and the roof deck. 

Synthetic underlayment is a newer innovation that is taking over the metal roofing industry as a better, more advanced replacement for felt underlayment. Most synthetic underlayments are mechanically attached with roofing caps and staples, while others have a glue backing.