Finishing the inside walls and ceiling of a room with drywall is a multi-stage process that will require you to apply coat after coat of compound to cover every joint left behind where large drywall boards were butted against each other to create uniform and flat surfaces all over the room. This is done with the use of a handful of specialized tools and materials to spread the compound over the joints, spreading it wider every time you return to it to finally achieve a perfect uniformity on an even drywall surface that can then be coated with primer and paint.
Dry walling, however, is not only about smoothing out flat surfaces. Ceilings and walls always meet other adjacent surfaces, sometimes at right angles, other times at different various angles. A rectangular room, for example, will leave you with 4 “inside” corners created by 4 walls meeting each other at a right angle plus 4 more corners where each wall meets with the ceiling, creating altogether 8 corners overall made very obvious by the cracks left at every joint.
Inside corners, although not as easily dealt with as flat surfaces, are not always that problematic or complicated to cover up. They will require a bit more work and skills to achieve, but they’re usually quite straightforward to plaster, providing that you have the right tape, compound mix, and of course the corner trowel along with the taping and finishing trowels. Outside corners, however, are a bit more particular to deal with involving the selection of specific outside corner beads.
When drywall is used to cover an outside corner or to wrap around the end of a wall, it leaves you with 1 or 2 somewhat rough uneven seams from the edges of the drywall boards, that you’ll later need to plaster to create a seamless edge. Since they are outside corners, once finished, they will be obviously exposed to blows and strikes from everyone that will travel around that specific corner of the room, and even worse when someone comes around carrying large or heavy objects. Therefore, outside corners have to be reinforced to withstand at least normal every day blows.
The Corner Beads and Their Purposes
Although corner beads are sometimes used to finish inside corners, they are not necessary, and paper tape is usually adequate and most often used for the job. Installed along the length of the outside corners of 2 angled walls, however, corner beads are designed to provide the exposed corners with extra reinforcement and add stability while concealing the seam between two drywall boards meeting at different angles.
Finishing a room that has walls meeting at odd outside angles might seem problematic but can prove to be no worst than walls meeting at right angles. Just as long as you get the proper drywall corner bead. There are several different types of corner beads available and they come in a variety of shapes, angles, and materials, covering different and specific situations you might be faced with. The first step is finding out at what angle your walls are laid out.
With that determined, you should know that off-angle beads come in 2 options, one that fits angles between 90 and 100 degrees, and the other option which can accommodate angles between 100 and 135 degrees. You can then decide—from what your supplier has available—what type of corner bead you would prefer to work with—paper-faced metal, vinyl, or paper-faced composite—considering both cost and ease of application.
But there really isn’t any best or worst corner bead overall—some beads are just better suited for certain situations and particular experience levels.
1. - Metal Corner Beads
The metal corner beads are the oldest types of beads used but are still very popular today. They constitute the cheapest option so far providing a perfectly straight corner even on irregular walls and corners. Even if they are easy to install, the thick metal beads take longer to put on and finish requiring a lot of joint compound to cover up and extra applications to fan out the corner evenly with the wall surface. Very sturdy, they provide the means to finish a corner and create a sharply defined edge even if the drywall wasn’t perfectly hung, covering up any possible flaws of the drywall edges.
Metal beads can be secured in place using screws, nails, or staples—screws being the most common method. Metal beads with special punch-outs that will allow the bead to be crimped in place using a special clinch-on tool. Metal beads are available as a 90-degree L-profile to give a sharp edge and also as a bullnose to give the corner a rounded edge. For off-angle walls laid out at over 90 degrees from one another, you can get special metal bead profiles. One of those common profiles covers from 90 to 100 degrees while a wider one covers between 100 to 130 degrees
There are downsides to using metal beads, however, due to their larger spine which causes a thicker application of joint compound as well as a wider feathering of the finish coat along with the use of mechanical fasteners, which altogether can impede building movements (settling) and cause cracks at the corners. Metal beads are also subject to rusting out in wet and damp areas.
How to install a metal corner bead
1.1 - Place the metal bead directly over the exposed corner where both walls meet.
1.2 - Push the metal strip down against the center of the corner to get the leaves on both sides of the metal strip to spread out evenly on both sides. If the drywall doesn’t completely cover the corner to the edge, thus leaving gaps where the boards meet, make sure that you don’t over-push it and keep the spine above both walls’ surface level. The leaves shouldn’t be forced into bending up at either edge.
1.3 - While holding the strip in that position, test its positioning by pushing it in place along the spine above and below, to make sure it will not buckle anywhere along its length.
1.4 - At about halfway up the length of the corner bead, use your nail gun, staple gun, screw gun, or your basic hammer and nails, and start securing the bead in place, attaching it on both sides or both leaves. You have to make sure that the fasteners are placed along the ribbed edge of the bead and far from the spine to keep the bead from curling up at the edges or buckling, thus ensuring a perfect corner.
1.5 - Moving down along the corner, keep on attaching the bead to the drywall, in the same manner, securing it in place, alternatively on one wall and then on the other. Keep securing in this manner until you get to the bottom end of the corner bead.
1.6 - Returning to the middle where you started nailing, screwing down, or stapling the corner bead, repeat step 1d but go up instead, and secure the bead right up to the top end. Once you have the installation completed, check to make sure that the corner is perfectly straight and that the metal corner bead sits flat everywhere. You can then proceed to finish the corner with the joint compound.
2.- Paper-Faced Metal Beads
Paper-faced metal beads are more expensive than metal or vinyl and while still offering rigidity, they are a bit more susceptible to damage than the traditional metal beads with the difference that they are faster to install but not as effective at covering up flaws in the drywall. Installed at the finishing while taping the joints, you might find it more difficult to master as it is secured with a ready-mix joint compound either applied by hand or using a special bead hopper and a corner roller. If the installation is not perfectly straight you may resort to nails or staples to hold in place.
On the positive side, although you’ll need a corner roller to install, the paper-faced metal bead will provide a very straight corner and uniform adhesion to the surface. The flexibility of the paper and joint compound also makes it less prone to cracking while using less joint compound to finish and fan out. It has been noted, however, that the paper-faced metal beads sometime tend to peel off the wall.
How to install a paper-faced metal corner bead
2.1 - Measure the height of the corner and cut your paper-faced metal corner bead about 1 inch shorter. Set it aside for the time being.
2.2a - Using your drywall putty knife, apply a generous coat of joint compound making sure to cover the full corner, top to bottom, and wider than the corner bead’s flaps, or ...
2.2b - fold the corner bead at its full length to make sure it will lay flat on both drywall surfaces’ and simply coat the inside of the corner bead with a “bead hopper”, which applies a uniform coat on the inside of the corner bead while you pull it through.
2.3 - While lining up the fold with the wall corner, press it into the mud to make it stick to the wall surfaces, and slide the top end to reach the ceiling.
2.4 - Making sure that the fold lines up with the wall corner, press the corner bead firmly in place.
2.5 - The best result for this step requires the use of a “drywall corner roller”. However, since your corner is at an outside angle wider than 90 degrees, you’re going to have to use an “adjustable or a self-adjusting corner roller” that can open up to the angle of your walls. Once you have the tool properly set up, place it halfway up the wall directly on the corner formed by the walls.
2.6 -The width of the rollers should be sitting flat on the corner bead. You can then start rolling the tool back and forth, lightly at first, back and forth over the corner joint, to get the corner bead to slide onto its intended and perfectly straight positioning on top of the joint. This will also squeeze out the excess compound from the edge of the corner bead.
2.7 - Using your drywall knife, spread the excess compound to cover the corner bead and feather it over a wider surface from the top to the bottom of the joint. Add more compound as needed to cover the 2 joints with a thin and even coat and let it dry.
2.8 - Keep plastering, adding more thin coatings over both walls, from the elevated bead to as far as you’ll need to get a perfectly even and straight surface, allowing the compound to dry fully before the next coat.
3. - Vinyl Corner Beads
Vinyl corner beads are less expensive than paper-faced metal and paper-faced composite corner beads. The corner bead’s raised spine either square, bullnose, or chamfered, makes it easier to apply the joint compound and conceal the bead, blending it into the wall surface, although it will require more applications of the compound. Vinyl beads can be secured to the drywall using staples, nails, screws, spray adhesive, or a special water-soluble adhesive added to the ready-mix. The fact that they can’t rust makes them more suitable for use in wet or humid areas such as bathrooms or basements.
Not being as rigid as other varieties of beads, you must take special care to install the bead as straight as possible, since an inadequate installation will make it difficult to achieve a proper finish. You can find vinyl corner beads in the widest array of profiles, designs, and sizes to accommodate any specific situation, down to the arch bead with notches on one side to make bending and forming it into a radius to create a smooth arch opening possible.
Although vinyl corner beads can be installed in different ways, using a spray adhesive before stapling it down to the drywall is usually what is recommended by the manufacturers. It should be noted, however, that joint compound does not bond as well to plastic making the finished corner susceptible to chip even under a light blow or collisions.
How to install vinyl corner beads
3.1 - Cut your vinyl corner bead to the right length for the height of the wall.
3.2 - Spray a coating of spray adhesive over the corner of the drywall and also on the inside surface of the corner bead, making sure all is well coated.
3.3 - Carefully bring the vinyl trim up to the top of the wall, lining it up perfectly along the drywall corner, while keeping the part at the bottom away from the wall. To stick the trim on, keep moving down and press it in place holding it for several seconds to make sure it stays stuck. Proceed like this until you reach the bottom while lining up the bead over the corner.
3.4 - Using a staple gun, you can now secure the vinyl corner bead in place, fastening it at regular intervals on both leaves of the trim.
3.5 - Once the corner bead is securely attached, you can start coating the corner on both sides with your joint compound, building it up with about 3 thin coats.
4. - Paper-Faced Composite Beads
Paper-faced composite beads offer the most expensive of the products and it can also be more difficult for beginners to use. It’s been proven to be more resistant to dent than vinyl, although as with the vinyl bead, it is more difficult to install and keep the edge straight, given its flexibility. The paper-faced composite beads also offer a good variety of profiles for various applications such as archways, niches, etc.
You can install those corner beads using a joint compound, just by hand which will be a bit tedious, or you can use a corner bead hopper to apply the compound, then press it in place with a corner roller, to provide you with a nice straight corner.
4.1 - With the right corner bead for the angle of the walls you’re working at, cut your corner bead to the right length for the height of your wall.
4.2a - Apply a good thick coat of joint compound over the full corner of the wall, covering both faces or ...
4.2b - pass the corner bead through a “bead hopper” to apply a constant even coating of joint compound on the inside walls of the corner bead.
4.3 - Lining up the bead of the trim with the corner of the wall, press the corner bead firmly into place with your corner roller, as the compound is squished in-between and coming out of the edges.
4.4 - Pick up the excess compound with a drywall knife, passing it over both sides of the joint, just leaving a thin coat feathering onto the wall surface. Leave it dry completely.
4.5 - Keep plastering the walls until you get a smooth uniform surface, 2 or 3 more coats.
If you choose to install a corner bead without using a corner roller, you can still do it with just drywall knives, but it will be a bit more difficult to achieve a perfect surface and a flawless straight corner.
There are many more articles on dry-walling that can you can access such as "How to Attach a Drywall Corner Bead", "How to Drywall a Metal Corner Strip", and possibly "How to Properly Use a Drywall Trowel". You just have to click on the link to be taken to another interesting journey to widen your horizons.