2510 LATHING AND FURRING FOR CEMENT PLASTER (STUCCO)

[sergoodo]

Need the forum stucco experts...
For an exterior stucco venerer wall (moist climate); over 1.5" closed cell foam; over metal studs 16" o.c.:
2510.5 Backing.
2510.5.1 requires solid backing.
2510.5.2.1 Gypsum lath or gypsum wallboard shall not be used as a backing for cement plaster.
2510.5.2.2 Gypsum sheathing is permitted as a backing for metal or wire fabric lath and cement plaster on walls.
2510.5.3 Backing not required. Wire backing is not required under expanded metal lath or paperbacked wire fabric lath.

Reviewing a system that does not have solid backing, but does have 'expanded metal lath or paperbacked wire fabric lath' I interpret that IBC requires the stucco over solid backing not foam.

Is the solid backing required?
What are rafters or other similar projecting members on vertical surfaces referenced below? IBC implying vertical metal or wood stud wall framing?

• 2510.5.1 Support of lath. Where lath on vertical surfaces extends between rafters or other similar projecting members, solid backing shall be installed to provide support for lath and attachments.

IBC saying that we can use exterior gyp as a backing board @ exterio wall as long as we provide a WRB and call it sheathing?

• 2510.5.2.1 Shall not be used as backing: gypsum lath, gypsum wallboard.
• 2510.5.2.2 gypsum sheathing is permitted as backing

 

[sergoodo]

In moist climates it appears the building code requires solid backing for exterior stucco (plywood/osb) Gyp products like densglass sheathing will not comply?

 

[Yankee Chronicler]

If going directly over foam, why are you using stucco as opposed to EIFS?

 

[sergoodo]

If going directly over foam, why are you using stucco as opposed to EIFS?

Plaster finish over foam insulation over solid backing in moist climates. EIFS is a plaster system also covered by CH25.