How to Tape and Finish Drywall Corners and Joints
To finish a joint properly, you will need wallboard tape and taping compound. Be sure to buy the precreased paper wallboard tape. Taping compound is also called joint compound, and comes in a variety of sizes. Also you will need a taping knife. The easiest way to apply wallboard tape is to use a 6 inch taping knife and a 10 inch taping knife for finishing work.
If you must also finish corners, you will need enough metal cornerbead for exterior corners. A corner tool is also very helpful when trying to finish interior corners.
To begin, apply a thin, very smooth layer of taping compound with your 6 inch taping knife. This layer should run the length of the joint, and fill in any holes from screws or nails. Next, take the wallboard tape and embed it into the layer of joint compound. The precreased line should approximately line up with the seam in the wall.
Over the wallboard tape and the joint compound layer, use your 6 inch taping knife to apply another thin layer of taping compound. While you are doing this, carefully smooth the tape, making sure that it is lying completely flat on the surface.
Wait twenty-four hours for the taping compound to dry. Wearing a face mask, lightly sand the joint, removing any imperfections. Using your 10 inch taping knife, apply a second layer of taping compound. Try to feather the edges, making the delineation between the taping compound and wallboard as slight as possible.
Let this second coat dry. Then carefully sand the area around your seam. Apply a second and final layer of taping compound using your largest taping knife. After that layer is dry, lightly sand and remove any imperfections. Even minor imperfections can easily be highlighted when painted or with light in a dark room, so be fastidious and remove any dimples or excess compound.
To finish an interior corner, the process is very similar. Apply your first layer of taping compound, just as before, covering both sides of the wall. Next, crease the wallboard tape vertically on the precrease to fit into the corner. Using a corner tool, apply the wallboard tape to the corner. If you do not have a corner tool, you can smooth both sides with a taping knife.
It is difficult with just a taping knife to get a perfect corner, so apply the tape carefully and take extra time to remove any puckers in the tape if you do not use a corner tool. Apply another thin layer of joint compound over the tape with the corner tool or taping knife. Finish the area as you would with any other joint.
Exterior corners use metal cornerbead for added protection on the joint. Often corners in a house receive the most damage, and the cornerbead protects the fragile gypsum board underneath. Use a thin layer of taping compound on the corner and press the metal cornerbead over the corner. Then apply another thin layer of taping compound over the joint.
Be sure there is enough taping compound to fill in every hole in the cornerbead. You may find, with surprise, that it takes more joint compound to finish an exterior corner with cornerbead. Finish the joint with the same procedure as you would with any other. Please note that you do not use the corner tool when taping exterior corners.
While you are taping joints in your wallboard, take the time to fill in any nail or screw holes that are not next to a joint. When you fill in holes, carefully use only a small amount of taping compound to fill in the indentation that the head left in the wallboard. Sand lightly after the compound is dry, and carefully assess whether the hole needs another coat of taping compound to blend in with the walls. Most holes should not need an extra coat of taping compound.
Taping and finishing joints in wallboard is a simple task that requires patience and a steady hand. If you do not feel you possess these qualities, call a professional. They will have to do the work over several days, but the cost should be minimal compared to other home improvement help.
