Field Register Drywall Insider

Field note

Stucco, lath, and plaster in the W&C package

Stucco, lath, and plaster are a wall-and-ceiling family the gypsum house still stocks: metal plaster base, weep and casing beads, corner aid, portland-cement plaster, and interior gypsum or veneer plaster. They are not drywall. Three-coat stucco is not a Level 4 corridor with a different hopper. Veneer plaster is not all-purpose compound.

Some commercial W&C shops still sell plaster and exterior stucco. Production residential hang crews usually do not. Read the invitation.

This page is takeoff language. Application of portland-cement plaster is ASTM C926. Installation of lathing and furring to receive it is ASTM C1063. Metal lath as a product is ASTM C847. Interior gypsum plaster and veneer plaster follow their own ASTM / mill documents (veneer finish is not C926). Fastener class for metal plaster base is ASTM C1002 Type A, not a bugle Type S hung as if it were board — see fasteners.

Gypsum houses such as FBM list stucco, lath, and plaster as a family. Confirm weight, backing, and accessories with the counter. Branch finder: myfbm.com. Hub: What a gypsum house stocks.

Three products, three crews

Exterior portland-cement plaster (stucco). Scratch, brown, and finish on metal lath over a weather-resistive barrier, or on masonry with or without lath as C926 allows. Weep screed at the sill, casing bead at openings, control and expansion joints in plaster language — not GA-216 gypsum control joints copied onto the elevation. One-coat proprietary stucco over foam is a mill system; it is not PB EIFS and not three-coat C926 unless the documents said so.

Metal lath (plaster base). Diamond mesh, self-furring dimpled, paper-backed (Grade D WRB attached where that is the detail). Weight (the “3.4 lb” class conversation) and furring are spec items. Self-furring dimples are how the plaster keys behind the lath on a solid substrate; flat lath on sheathing without furring is how you fail the embedment the standard is talking about.

Interior plaster. Gypsum plaster on lath or on gypsum base, including veneer plaster over a blue-board / plaster-base panel. Veneer is a thin mill system with its own base and finish. It is faster than three-coat and harder than a GA-214 Level 5 skim in the wrong hands. Do not bid veneer as “Level 5 with a different bag.”

Do not mix bags: EIFS base coat, stucco brown coat, veneer plaster, and ready-mix joint compound are four products.

Who owns the package

W&C shop owns stucco / plaster. Common where the company still markets plaster or exterior cement finish next to metal stud and board. Then lath, accessories, plaster labor, and scaffolding or pumps are not a hang rate. Directory: Specialty installation.

Separate plaster / stucco contractor. The drywall sub still owns interior gypsum, often the backup, and the interior returns at openings. Exterior lath and plaster by others. Write it.

Lath only / backup only. You hang sheathing or frame the backup; plaster by others. Paper-backed lath is not a substitute for the WRB the wall type named unless the documents made it so.

Residential production: stucco on a production house is typically a cladding sub, not the hang trailer. Interior plaster in a new production house is rare; the crew is tape and texture. A historic rehab with three-coat interiors is a plaster job even if a drywall shop won the rest of the floor.

Accessories shops miss

Stucco takeoffs die on trims, not on the field coat:

Interior plaster misses the plaster base panel (not regular wallboard), the mill’s veneer system, and control joints in large gypsum-plaster planes.

Where stucco returns meet interior board, that return is hang and bead unless you excluded it.

Bid notes

Split even inside a lump-sum W&C number:

If plaster is not yours: exclude lath, plaster, and stucco accessories; include interior gypsum only; show the joint at the plaster return.

Confirm specialty trims with the yard before the elevation is open. National web aisles are not floor stock. Will-call is how a missing weep screed stops a crew.

Commercial vs residential

Commercial wall and ceiling. Exterior stucco on CFS or masonry backup, interior plaster in stairs, restoration, and some institutional walls, veneer in a few markets that still specify it. Fire-rated plaster assemblies are listed systems — not “Type X with mud on the outside.” Coordinate with exterior CFS and sheathing.

Residential production. Hang, tape, texture. Stucco elevations are a different sub in most metros. Do not send the house taper to scratch-coat. Townhouse and mixed-use with cement plaster on the podium follow the commercial documents.

Related

Family map: What a gypsum house stocks. EIFS next to plaster: EIFS and the drywall sub. Gypsum joints (different document): Drywall control joints. Fastener class: Type S vs Type W, Fasteners. Yards: Distribution, FBM.

FAQ

Is stucco in the drywall number?

Only if the shop sold it. Many W&C companies still do. Production hang shops usually do not. Read the invitation.

Can I use drywall corner bead on stucco?

No. Plaster corner aid and stucco casing are different profiles. Interior bead is a gypsum finish accessory.

Is paper-backed lath the WRB?

Only when the documents treat that backing as the barrier. Many walls still want a separate WRB plus lath. See exterior sheathing and WRB for the sheathing side.

Is veneer plaster a substitute for Level 5?

No. Veneer is a plaster system on a plaster base. Level 5 is a gypsum skim. Different mill, different labor, different look.

Does the gypsum house stock lath?

Interiors houses list stucco / lath / plaster as a family. Weight and backing vary by yard. Confirm; use the finder on myfbm.com.

All field notes