Vinyl Siding

Vinyl siding is composed of a PVC substrate that has a thin layer of PVC or acrylonitrile-styrene-acrylate (ASA) capstock fused to it. It is commonly installed over OSB or plywood sheathing and a water-resistive barrier. Nail slots are punched into the siding to allow for expanding and contracting around the corrosion-resistant fasteners that are used to attach it to the building. A layer of foam insulation, commonly expanded polystyrene (EPS), may be applied under the siding as insulation. Alternatively, insulated vinyl siding is available that contains a layer of EPS laminated to the vinyl siding with an adhesive. Some products add a topcoat to reduce fading. These are not well disclosed, but coatings that appear to be PVDF are used in some cases.   

Some manufacturers offer take-back programs to recycle vinyl siding into other vinyl products. Data supplied by the industry indicate that vinyl siding can be recycled back into the vinyl siding substrate, but no products were identified in this review that claimed to use post-consumer recycled content. One manufacturer in this review indicated that they were using pre-consumer recycled content, which would come from a closed-loop recycling process used to recycle scrap and trimmings back into vinyl products.   

This Common Product describes vinyl siding using virgin PVC in the substrate and an ASA capstock, with no insulation or coating. In addition, various pigments can be used that may add additional hazards. The capstock layer typically constitutes about 10 to 15% of the products’ weight. Very limited data was available on percentage of contents within each individual material, so this CP does not break out the substrate and capstock into two materials but reports percentages in the product overall.