A common question we receive is “How long of a fastener do I need when installing insulated vinyl siding?”.
The vinyl siding institute recommends that your fastener penetrates into a nailable service, such as wood sheathing or a stud, at least 1-1/4″. With hollow vinyl siding, a 1-1/2″ nail can be used.
With insulated siding, you have to take into account the thickness of the insulation. For instance, if using a 1/2″ of insulation, you need at least a 2″ nail. When in doubt, use a slightly longer nail.
As always, when in doubt, check your siding manufacturer’s installation requirements when determining the required fastener length.