Taping Drywall Joints Taping Drywall Joints
Installing (or hanging drywall) is a relatively straight forward job that most home owners can take on themselves. Where, most folks start to get uneasy is the idea of finishing the drywall installation, - the taping and mudding. A properly finished wall should not have any joints or nails visible, and achieving that perfectly smooth wall can be a challenge that many people would rather to leave to the pros. However, if a homeowner is prepared to take their time and (probably most important) invest a little money in the proper tools, they can achieve results equally as good as the pros.
This article assumes you have already installed your drywall, minimizing the number of joints by running the panels horizontally and also aligned the majority of sheets factory edge to factory edge. (This is important because drywall sheets are slightly narrower at the finished edge specifically to accommodate the joint compound (mud) necessary to fill the seam. Placing cut edges to cut edges makes the job of hiding the joint more difficult).
You have a choice in the type of drywall tape you want to use. Most pros use a plain paper drywall tape that is held in place with joint compound however, adhesive backed fiberglass tape is also available. The sticky back holds the fiberglass tape in place and many amateurs find it easier to use.
Start by spreading a thin coat of mud (with your 6" knife) into the recess where the drywall edges meet and make it smooth with the surface. Center your tape over the joint and use your knife to press it firmly into the mud. Hold your knife at a 45 degrees and apply enough pressure to get some of the mud coming out from under the tape. Smooth out the edges by feathering the sides - working away from the joint. Once the taping is done, let the mud dry (overnight).
Taping inside cornersMeasure and cut your tape to length, then fold it in half lengthwise. Apply the bed of mud and press the tape into the joint with your knife. On the first coat, spread the mud out about 2 inches on each side. Inside corners will require 3 coats with the final coat extending about 8 to 10 inches out from the corner.
Outside corners should have been covered with a metal or fiberglass "corner bead" that nailed into the underlying studs. Corner beads have a "nose" or bump right on the corner edge. On the first coat of mud, spread it along the length of the corner bead and extending about 4 or 5 inches away from the edge. Keep the edge of your knife on the corner bead and the mud will fill in the gap. Your second coat should extend about 6 to 8 inches from the corner and the final coat 10 to 12 inches.
After the mud for the tape has dried, give the edges a quick scrape with your 8" knife to remove any small bumps. Next, apply a generous layer of mud directly over the joint (tape) and spread it evenly. You want to end up with an area that is about 6 to 8 inches wide cover the joint with the edges feathering out smoothly. Once again, allow the mud to dry overnight.
Applying the final coat is when you use your largest knife. Once again, start by scraping away any small bumps and imperfections. The final coat is really just a skim coat, to hide the seam, so you wonât be applying as much mud as with the previous coat. Spread the skim coat over the joint and use long smooth stroke feather it out away from the joint. The objective with this final coat is to end up with a strip about 12" wide (obviously with the joint in the center) that smoothly flows down to the level of drywall surface. Again let your joint compound dry overnight.
Unfortunately, now you are going to have to do some sanding. Close off the room by hanging plastic sheets over the doorways, to contain the dust. If you've feathered the edges of the seams on each of the mud coats, you won't have any significant amount of sanding, but be safe and wear a dust mask. Use a pole sander and medium grit sandpaper to lightly sand the edges and blend them into the wallAn even better alternative to the pole sander is an attachment for a shop vacuum (available at home stores), that uses a pole and an open screen fiberglass sanding material to smooth the joint compound. This actually sucks most dust directly into the vacuum, before it gets into the air and makes dry walling much less messy.TIPS:
It's important to use different sized taping knives. Many homeowners think they can save a few dollars and use a 6 inch knife for all the mudding and feathering. It's very difficult to feather the final coats using such a small knife and the final results just won't look good.
Before doing anything else to your walls, the joint compound dry for about a week and then apply a coat of primer. Primer isn't just paint, it actually helps to seal the wallboard, and will stop paint from being soaked into drywall.
Finally, and most important, take your time when finishing your walls. You're going to be looking at them for a long time so take that extra time up front and you'll end up with a wall that a pro would be happy to call their own.