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Drywall Corners and Beads: Metal, Vinyl, Paper-Faced and Bullnose Bead, Inside Corners, Off-Angles, and Why the Corner Is Where Cheap Taping Shows
Drywall, Taping & Painting
Corners and Beads: The Place a Wall Gets Hit, the Place Cheap Taping Shows, and the Four Kinds of Bead and When Each One Cracks
Every outside corner in a house is a strip of metal or plastic buried in compound, and every one of them will get hit by a vacuum, a chair or a moving dolly in the first year. The bead is what makes the corner survive it. Every inside corner is two sheets meeting at 90 degrees with paper tape folded into the angle, and it is the hardest joint in the house to finish straight. Tapers price corners separately because they are slow, and you should count them, because a square bedroom has four and a basement with ductwork has forty.
Outside corner bead: the four kinds
| Bead | What it is | Strengths | Weaknesses |
|---|---|---|---|
| Galvanized metal | The traditional 90-degree angle, nailed or crimped on, 8 or 10 ft lengths. | Strong, cheap, sharp corner, takes a hit. | Dents if hit hard enough and the dent stays. Can rust through the paint in a damp basement. Nails pop if the framing moves. |
| Vinyl | Rigid plastic angle, stapled or glued with spray adhesive. | Does not rust or dent; springs back from a hit. Easy to cut. What most Ontario tapers use now. | Needs enough compound over it; thin coverage chips at the edge. Movement cracks along the edge if it is stapled too tight. |
| Paper-faced metal or composite (Trim-Tex, Strait-Flex, No-Coat) | A metal or plastic core with paper flanges, bedded in compound like tape. | The compound bonds to paper instead of metal, so the edge does not crack. The best corner there is. Flexible versions do any angle. | Slower to install (it is bedded, not nailed). Costs more. The cheap taper will not have it on the truck. |
| Bullnose (rounded) | Vinyl or metal with a 3/4-in. radius. | Soft corner, no sharp edge to chip, hides small misalignments. | Hard to paint a colour change at; baseboard and casing need special returns; dated in some eyes. Twice the labour. |
Inside corners
An inside corner is paper tape creased down the middle, bedded in compound, and then coated one side at a time so the knife does not drag through the wet side. A good taper uses a corner trowel or an angle head on a box for the first coat and a 6-in. knife for the rest, and the corner comes out straight and sharp. A bad taper uses mesh, or coats both sides at once, and the corner is wavy, rounded and cracked by Christmas. If you want to judge a taper’s work in thirty seconds, look down an inside corner from one end with a light at the other. Why paper.
Off-angle corners, where a cathedral ceiling meets a wall at 110 degrees or a bay window wall turns 45, are where paper tape cracks because the fold is not supported. The paper-faced flexible composite tapes are made for exactly this and cost about $1 a foot; a taper who does cathedrals without them is leaving you a crack along the whole length. Ceilings.
Counting corners, and why it changes the price
Each outside corner is a length of bead, fastened, and two extra coats of compound feathered out a foot each side. On a $1.50 a foot Level 4 job, a corner adds about $9 in labour and material, which is nothing in a square room and $350 in a basement with 38 of them. Window returns, where the board wraps into the window opening instead of a wood jamb, are four corners per window. Bulkheads are two or four corners per foot of length plus two ends. Arches are the expensive ones: flexible bead, more coats, and the price is double. When a basement quote is 20% higher per foot than the main floor, this is why, and it is legitimate. The taping calculator asks for the count.
Where homeowners go wrong
- Metal bead in a damp basement. Rust stains come through the paint in a few years. Vinyl or paper-faced.
- A dented corner left for the painter. Metal dents stay dented. It needs a new piece of bead, which is a taper’s job, before paint.
- Bullnose with a hard colour change. There is no edge to cut a line against. Pick one colour on both walls or pick square corners.
- Cathedral corners with ordinary paper tape. It cracks. Flexible composite tape, and put it in the contract.
- Not counting the corners before comparing quotes. The quote that counted them is higher and honest.
Questions people ask
What is the best drywall corner bead?
Paper-faced metal or composite bead, bedded in compound: the compound bonds to paper, so the edge does not crack, and the core takes a hit. Vinyl is a close second and what most tapers use. Plain metal is fine in dry rooms and rusts in damp ones.
How much does corner bead cost?
Vinyl or metal is about $3 to $4 for an 8-ft length; paper-faced about $8. Installed and finished, a taper charges around $9 a corner on top of the per-foot rate; arches and bullnose double.
Why do my drywall corners crack?
Outside corners: the bead was nailed too tight, the framing moved, or the compound was too thin at the edge. Inside corners: mesh tape, or both sides coated at once, or an off-angle corner done with plain paper tape. The fix is to cut back and redo the corner with the right product.
Should I choose bullnose corners?
If you like the soft look and want one wall colour throughout, they are durable and forgiving. If you want colour changes at corners or crisp modern trim, square corners. Bullnose costs about double per corner and complicates baseboard and casing.
Count them and price them
The taping calculator has a corner count. The inspection checklist includes sighting down every corner with a light before the primer goes on.
Sources and further reading
- Gypsum Association construction standards: GA-216 application and finishing (the hanger’s bible: fastener spacing, ceiling framing limits, joint treatment) and GA-600 fire resistance design manual, with the free downloads.
- CGC Inc.: the maker of most of the board and compound in Ontario; the product sheets give thicknesses, span limits for ceilings and the right compound for each coat.
