Insulation Plastic Cap Nails And Metal Screws
Typically, to fasten rigid foam boards to wooden studs, we use broad-headed fasteners – mostly plastic cap nails (roofing cap nails).
To fasten rigid insulation to metal studs, instead of plastic nails, builders use mostly sheet metal screws with rubber washers.
The insulation fasteners should be long enough; they should penetrate about 3/4 of an inch into the framing.
In some cases, when the weight of the insulation panels is significant, the fasteners must solve two problems: how to fasten the panels securely to a wall, and how to do fasten the siding securely to the panels.