Field note

EIFS and the drywall sub

EIFS (exterior insulation and finish systems) is a cladding: foam, reinforcing mesh, base coat, finish coat, and the flashings the system mill named. It is not gypsum, not stucco, and not a silent extra on a Type X takeoff. Some commercial wall-and-ceiling shops sell it. Many only hang the sheathing and leave the lamina to a specialty contractor.

This page is scope language for the drywall / W&C estimator. It is not an applicator manual and not a mill catalog. Class documents to have on the desk: ASTM E2568 (Class PB EIFS), ASTM C1397 (application of Class PB EIFS), the drainage-EIFS notes in the spec (water-managed systems, not barrier PB by habit), IBC exterior-wall and plastics chapters, and NFPA 285 where the assembly uses combustible foam on a commercial wall that the code flags. Pull listings from the system mill, not from last job’s foam thickness.

Gypsum houses such as FBM stock EIFS as a family on public category pages. That is a map, not a floor-stock guarantee. Confirm components with the counter; use the branch finder on myfbm.com. Hub: What a gypsum house stocks.

What the system is — and what it is not

Class PB EIFS is the usual commercial and residential product: expanded-polystyrene insulation adhesively and/or mechanically attached, glass-fiber reinforcing mesh embedded in a polymer-modified base coat, and a textured finish coat. Drainage / water-managed EIFS adds a drainage plane and flashing package the barrier-PB detail did not have. Do not bid one as the other.

Not this page: Continuous insulation behind brick, metal panel, or another cladding. ci is an energy layer. EIFS is a cladding that includes foam. Hanging rigid foam on CFS backup without the EIFS lamina is the ci conversation, not this one.

Not stucco. Portland-cement plaster on lath is ASTM C926 / C1063. EIFS mesh is not metal lath. A “one-coat stucco over foam” system is still not PB EIFS unless the documents named that EIFS mill.

Not interior gypsum. Finish coat on EIFS is not a GA-214 level. Do not tape EIFS aesthetic joints like a corridor.

Who owns the package

Three common splits. Read the invitation.

W&C shop owns EIFS. The same company that sells metal stud, board, and sometimes plaster also applies EIFS — usually because the shop already has a plaster / EIFS crew and certified applicators the mill requires. Then the estimate still splits: lamina labor is not a gypsum hang rate, and mill certification, if any, is a bid condition. Directory: Specialty installation.

Specialty EIFS / plaster contractor. GC buys EIFS from a mill-network applicator. The drywall sub meets the system at every opening, deck edge, and interior partition that dies into the backup. That meeting is your detailing problem even when the finish coat is not in your contract.

You hang sheathing only. Glass-mat or gypsum sheathing on exterior CFS or wood, ASTM C1280 / GA-253, then WRB / EIFS by others. Write the exclusion: EIFS furnish and install by others; sheathing and joint treatment of the sheathing only as the board mill named — not as interior tape and mud.

Residential production almost never owns commercial PB EIFS. A production house with foam-and-mesh on the elevation is still a cladding crew, not the hang crew, unless the shop actually sells that system. Mixed-use podiums follow the commercial rule.

Substrate, WRB, and the drywall number

The backup is often the wall-and-ceiling package even when EIFS is not:

1. Exterior CFS or wood / masonry as drawn.
2. Glass-mat sheathing (ASTM C1177 class) or the sheathing the EIFS mill listed. Interior paper-faced wallboard is not a cladding substrate.
3. Joint treatment the sheathing mill and the EIFS mill both accept. Do not Level-4 a DensGlass-class face.
4. WRB or liquid-applied barrier as the drainage-EIFS spec named. Barrier PB that relied on the lamina alone is not a silent substitute for a drainage assembly the documents bought.
5. EIFS lamina by whoever owns it.

Openings, starter track, aesthetic grooves, and expansion joints are EIFS mill details. Window returns that wrap with gypsum on the interior are still hang and bead — count them.

NFPA 285. Combustible foam on many commercial exterior walls is an assembly test, not a foam R-value. If the wall needs 285, the listed stack (sheathing, barrier, foam, lamina, and any ci or claddings in that listing) is the takeoff. Substituting a different foam thickness or mill because the yard had it is how you fail the listing.

Bid notes

Price as separate lines even inside a lump-sum W&C number:

• Sheathing mill, thickness, and fastener class (not interior Type S by habit)
• WRB / drainage plane if it is yours
• EIFS system mill, foam thickness, mesh weight (standard vs high-impact), finish coat
• Starter, expansion, and aesthetic accessories the mill named
• Opening wraps and flashings
• Mockup if specified
• Certification / warranty paperwork the mill requires

If EIFS is not yours: exclude furnish and install of foam, mesh, base, finish, and EIFS accessories; include backup and sheathing only as shown; require the applicator on site before you close details they have to flash.

Do not invent unit prices from another market. Do not copy a catalog SKU onto a bid from a national web aisle. Confirm with the counter that will load the truck — gypsum-house will-call if it is a short run of mesh or starter; scatter if it is a foam elevation.

Commercial vs residential

Commercial wall and ceiling. EIFS on CFS backup, masonry, or mixed podium. Fire-tested exterior walls, drainage details, and mill listings. The drywall sub’s default is sheathing and backup unless the shop sold the lamina.

Residential production. EIFS on wood frame is a specialty cladding in most markets, not the hang-and-tape trailer. Do not send a production taper to embed mesh. A townhouse with EIFS on the street elevation and gypsum inside is two contracts that meet at the window return.

Related

Family map: What a gypsum house stocks. Yards: Distribution, FBM. Sheathing and ci: Exterior sheathing and WRB, Continuous insulation. Plaster next door: Stucco, lath, and plaster.

FAQ

Is EIFS usually in the drywall sub’s number?

Only if the shop sold it. Backup and glass-mat sheathing often are. Foam, mesh, and finish coat are a separate yes/no.

Is EIFS the same as continuous insulation?

No. ci can sit behind another cladding. EIFS is the cladding. See continuous insulation.

Can I use leftover drywall mesh in EIFS base coat?

No. EIFS reinforcing mesh is a system component. Interior joint tape is not a substitute.

Does a gypsum house stock EIFS?

Specialty interiors houses list it as a family. Floor mix varies. Confirm the system mill and the accessories with the counter; use FBM’s finder on myfbm.com rather than an invented yard list.

Does NFPA 285 apply to a house?

The 285 conversation is a commercial exterior-wall assembly test. Residential wood-frame EIFS follows the residential code path the documents named. Do not copy a commercial listing onto a production house, or the reverse.

All field notes