Field note
Corner bead types for drywall finish
Outside corners are an accessory, not folded tape. ASTM C1047 is the material spec for corner beads, casings, and related trims used with gypsum board. GA-216 / ASTM C840 tell you they have to be attached so they stay straight. The finish level on the plane does not change because you picked vinyl — a wavy bead still photographs under Level 4.
This page is takeoff language for the bead truck. It paraphrases public C1047 / GA-216 class language and mill install notes from Trim-Tex (vinyl), USG (paper-faced and metal families), Grabber corners, and peers. It is not a SKU catalog. Control-joint profiles are a different accessory — drywall control joints. Directory: Finishing, Products.
Three material families
Metal (zinc-coated steel). The traditional rigid nosing. Flanges are nailed, stapled, clinched, or — on some profiles — screwed. C1047 wants zinc-coated steel, edges free of burrs, no twist that keeps the bead from sitting. Metal dents. A cart in a commercial corridor will telegraph. Repair is a new length or a lot of setting compound. Rust at a wet cut is a finishing problem if the coating was cut up and left raw in a humid room.
Paper-faced metal. Steel nosing with paper flanges. The paper is the bond surface: you mud it on (embed in compound, often setting-type) instead of nailing the nose full of fasteners that telegraph. The corner can float straight on the mud. It still dents like metal. It is not joint tape — do not use paper tape as an outside-corner bead.
Vinyl (rigid PVC). Dent-resistant, does not rust, trims with snips. Trim-Tex is the production name most shops use for the class. Attachment is mill-specific: spray adhesive plus staples is the everyday vinyl sequence; some profiles are mud-on or water-activated adhesive. Vinyl does not like a nail pattern copied from metal. Fast-set compound is accepted by many vinyl houses — read the folder. Impact in schools, hospitals, and garages is why vinyl sits on those takeoffs.
C1047 also allows other suitable materials. The spec is a floor, not the finish system. Follow the bead manufacturer for attachment and the first coat. Setting-type vs drying still applies: lock the bead, then finish with a sandable coat.
Profiles the takeoff actually names
Square (90°) corner bead. Default outside corner.
Bullnose. Radiused nose — commonly 3/4-inch and 1-1/2-inch class radii. Needs a matching radius on the gypsum cut and a different mud build. Do not hang square bead and “round it with mud.”
Arch / flexible. Slotted or segmented flanges for curves. Cut the gypsum to the radius; the bead follows. Forcing square metal around an arch is a crack.
Off-angle / splayed. Obtuse or acute corners, coffers, vaults. Square 90 bead on a 135-degree soffit stands off one flange.
L-bead / J-bead / LC and LK casings. Terminate gypsum at an opening, a dissimilar material, or a reveal. Tear-away L is the production opening bead: hang past, finish, snap the tear-away for a clean caulk edge against a frame. These are not corner beads, but they live on the same accessory takeoff.
Reveal and expansion accessories. Architectural reveals and control joints are specified profiles. A corner bead is not a control joint.
Inside corners are paper tape (or a paper-faced inside-corner trim), not an outside bead folded backward.
Hang first, then the bead
Beads do not straighten a belly. Framing and hang still have to be in plane — how to hang drywall. Cut gypsum back enough that the nose sits proud and the flanges land on paper, not on a void. Overlapping beads at a three-way corner wants a plan (one piece scribed, or a manufactured cap) so you are not stacking three noses.
Fasteners through a metal flange that miss the stud do nothing. Vinyl staples that miss still hold if the adhesive did its job — until the corner takes a hit. Run a straightedge. A Level 5 corridor will show a bowed nose the taper cannot hide.
Commercial vs residential
Commercial wall and ceiling. Vinyl or paper-faced on corridors and anything that will take carts; metal still shows up where the spec is old or the shop is metal-only. Tear-away L at storefront and HM frames is a commercial finish detail, not a residential casing habit. Abuse walls still want a bead that can take a hit — vinyl, or a specified impact corner, not the cheapest metal on the trailer.
Residential production. Metal nail-on remains common on production houses; vinyl and paper-faced are upgrades or punch tools. Bullnose is a plan detail, not a field invention. Texture does not hide a dented metal nose in an entry.
Bid notes
- Count lineal feet by profile and material, not one “bead” lump.
- Attachment method is labor: nail-on vs spray-and-staple vs mud-on are different rates.
- Arch, bullnose, and off-angle are extras. Square 90 does not cover them.
- Openings: L / J / tear-away as the frame detail requires.
- Do not invent SKUs. Name the class (vinyl square, paper-faced 90, metal bullnose) and the mill on the submittal.
Related directory
Finishing, Products, Trim-Tex, USG, Grabber, National Gypsum. Finish: Drywall finishing levels, Setting-type vs drying compound. Joints that are not corners: Drywall control joints.
FAQ
Can I use paper tape as an outside corner?
Not as the accessory. Outside corners want a C1047 bead. Paper tape is the inside-corner and flat-joint reinforcement.
Does vinyl need primer before paint?
Follow the bead mill. Many vinyl profiles are painted with the wall after compound. Do not assume a metal-bead primer habit.
Why does metal telegraph fasteners?
Nails or staples too close to the nose, or a flange that is not tight. Paper-faced mud-on exists to get the fasteners off the nose.
Is bullnose a Level 5 problem?
Bullnose is a profile. Critical light still shows a wavy radius. Hang and bead straight, then finish to the specified level.
Do commercial specs allow vinyl?
When they name it or name C1047 without restricting material. If the spec says metal only, vinyl is a substitution. RFI it.