Finishing Drywall: Tape and Joint Compound
From: DK - Do It Yourself Home Improvement
Finishing drywall involves typically three to four days of work and a great deal of joint compound. The type of joint compound you use to smooth seams and cover nail holes will depend on the size of your room and your level of experience. The entire process from taping to finishing the final coat can take four days, because of the drying times of the joint compound. Make sure you have allowed enough time to finish each step completely before starting the next.
If you have never completed a drywall project on your own before, and you still do not feel comfortable about tackling a drywalling job after reading the steps in this section, it is a good idea to hire a professional. In order to find a reputable contractor, contact your local chapter of the National Association of the Remodeling Industry (www.NARI.org) or search for a regional association of drywall professionals online. For example, there are drywall organizations for professionals across the country from New Jersey to Nebraska and California. Drywall contractors also usually offer painting and other finishing services.
It may seem like drywalling is a time-consuming, labor-intensive process. In spite of this, the reason drywall has become a standard wall covering is that it takes fewer finishing skills, and less money and time than the traditional alternative of plastering walls. If you have an older home, and want to have a plaster finish to keep consistent with the construction of your home, it is possible to use drywall instead of lath and finish with plaster. It will take longer to accomplish, but you will be able to use the plaster to create any texture patterns in the wall or ceiling surfaces that you may want.
At every seam where two pieces of drywall meet, and where there will not be any beadboard or other trimwork covering the panels, you will need to fill the seam and create a seamless transition between the panels. The objective to finishing drywall or finishing with plaster is to create the illusion that the wall consists of one flat piece.
The advantage of installing flat panels of drywall is that there is less finish work after the panels are installed and planning the panel layout to reduce the number of seams will further minimize the time you will need to invest in taping and finishing it. Every seam and every screw hole will need to be covered with joint compound, and each seam requires further steps.
Finishing drywall joints involves three basic steps that can take as many as four days to properly complete. The first step is called the taping step. The second step is called the filler step, and the third step is the finishing coat. Each step involves applying a layer of joint compound that is wider than the one before.
Before starting the taping process, make sure corner bead is installed on all outside corners around the room. Inspect the walls and ceiling to make sure that all of the screw or nails are firmly embedded into the drywall sheets. You can do this by running a taping knife over the surface of the wall. If you hear a tap when going over a surface, it means that a screw or nail will need to be tapped further in.
First Coat (Taping Coat)
The first step in the finishing process is called the taping step. During this step you are embedding drywall tape over the joints in the walls and ceiling. Some DIYers will choose to use a fast-setting compound for this first step. While fast-setting compounds will speed up the long process of finishing drywall, the time available to you to work with the material is greatly reduced. This in turn will affect the quantity of compound you will have time to apply, so you will need to judge carefully how much compound you mix with water to begin with.
If you're working with premixed compound, do not stir the compound too vigorously in the bucket. If you stir it too much you can work air into the mixture, which will create little bubbles and craters on the surfaces.
Use a 6" taping knife to apply the joint compound along the seam. Be generous with the joint compound at this point. Spread out more than you need to fill the seam. Try to work as neatly as possible, but keep in mind that it is not as important to have a perfectly smooth surface when you finish this step. The objective is to make sure that the tape is completely embedded and rests flat over the drywall seams.
Lay a piece of joint tape over the center of the joint, pressing it lightly with your hand to make it stick. Place more joint compound on your knife, and pass it back over the tape. This will embed the tape. Make sure the tape lays smoothly across the joint.
Applying First Coat of Compound
Apply a thin layer of joint compound to the seam. Press tape into the joint compound along the seam. Then apply joint compound over the tape with a drywall knife.
Smooth the compound into place. Let it dry completely and then sand it with a pole sander to remove large imperfections. You do not need to smooth down the finished surface.
Applying a Second Coat (Filler Coat)
After the first coat has completely dried, and you have removed any really noticeable imperfections with a pole sander, it is time to apply the second coat of joint compound. For this step, you may find it easier to use a wider drywall knife, because you will be covering the first strip of compound and blending it further across the wall surface. Select a 6" to 12" knife.
You will be building up the drywall joints a little more and then feathering them out smoothly. This step requires a more refined technique than that used to apply the first coat. The joint compound is applied with a little less pressure and a lot more patience. Of the three compound application steps, you will be using the greatest quantity of joint compound. Make sure you have more on hand than during the taping step. In order to achieve a natural-looking feather along the joint, apply more pressure on the outside of the knife and let it ride a little high in the center as you slide it along the seam. If you have applied enough compound correctly, you will not be able to see the joint tape any longer. Be sure to fill and cover all nail and screw holes with joint compound.
The finish coat requires real artistry because you don't want to leave any grooves or streaks after you have finished. The aim is to achieve a base that is as smooth as possible for this final coat. So, before you begin, scrape a wide knife over all the joints to smooth them out a little, which will remove the ridges and tool marks.
Applying a Second Coat
Using a 10" drywall knife, apply a second coat of joint compound to each seam. Feather the edges of the joint, and make sure there are no air bubbles in the compound.
Applying the second coat of compound takes more finesse than the first. Using a wider knife and smoothing any imperfections are ways of creating a successful finish.
Start at the center of the seam, pull the joint compound across the seam. Apply pressure to the outside edges of the knife as you pass over the joint. Pass over the joint to feather the compound out. Continue to pass over the joint until the air bubbles are removed.
Applying the Third Coat (Finish Coat)
If you were able to spread smooth, blended layers of joint compound during the previous two steps, your work during the third coat will be easier. After the second coat is dry, smooth a pole sander across any bumps or humps. You may want to shine a light across the surface to identify the joints that may need extra attention during this third coat.
While some DIYers prefer to use premixed joint compound right out of the bucket, it is possible to add a little water to the premixed bucket during this step. In fact, if you plan to use the paint-roller technique below, you may want to add water to thin the mixture, which will make it easier to smooth the compound onto the wall. Using a paint roller with an extension will also make it easier to apply the third coat to any ceiling joints. You will need a trowel to finish the seam, however, after you apply the compound with the roller.
If you choose to use a drywall knife for this finishing coat, choose a knife that is wider than the one you used during the previous step. A 10" or 12" knife will work perfectly well. The objective of this step is to achieve a smooth feather. The aim is to end up with as few imperfections as possible, because each imperfection will require more work during the sanding step.
Prepare the drywall joint compound to begin with, adding water to the joint compound mix if needed or lightly stirring a premixed tub. You can add a little water to a premixed tub to make it easier to spread. Only prepare as much of the compound as you plan to use immediately, because it can dry out.
Using a paint roller and paint tray, spread the joint compound across — and wider than — the previous coat of compound.
Use a trowel to smooth the compound for a seamless finish.
Copyright 2009 Dorling Kindersley Limited
Text copyright 2009 Julian Cassell and Peter Parham