Installing r-tech insulfoam to exterior sheathing?

Question

i'm building an addition, and plan to stucco it. i already installed my j-weep, and vapor barrier. since we live in phoenix, i plan on installing 1" sheets of r-tech foam over the vapor barrier, then install my lathe. what kind of fasteners are best for attaching foam to OSB sheathing? and what about the metal lathe (which will be self-furring chicken-wire)? i assume the fasteners for the lathe need to penetrate all the way to the OSB, right? any help would be great. thanks.

Answer 1

Walls, check.

vapor barrier, check

Foam  Attached with at least 3/4 of an inch penetration past the foam and vapor barrier, screws work best as they do not back out. Adding a plastic washer to the head will help spread out the surface tension and prevent the board from breaking at the s***w head.

Lathe, should actually be the galvanized expanded metal and not chicken wire, chicken wire will rust through which can lead to the premature failure of the wall, cracking and settling.

Attach the lath with the same screws and washers, I actually put just enough in the foam to steady it and then add the lathe and finish the attachment that way. attach every 12 inches up and down, and every stud side to side.

Watch the metal, it bites!!

Luck