Drywall is the most common wall covering material in homes. It’s made from gypsum, which is mixed with additives to create a slurry that is sandwiched between two layers of paper and then dried.
You’ll need a couple of drywall knives (a five inch and a ten inch), a utility knife, and some sanding equipment. You may also want to wear a dust mask.
Tape the Joints
Drywall is a relatively cheap material that allows builders to create rooms much faster than with wood framing. It also offers a smooth surface that’s easy to paint and is perfect for concealing wiring, plumbing or other unsightly elements in a room. Properly taping drywall is a fine art that takes practice to master, but it’s well worth the effort when you want your finished wall to look as flawless as possible.
The first step is to apply a thin layer of drywall joint compound (also called “mud”) over the tape and nails. This mud is a mixture of limestone, emulsifiers, various polymers and water that’s used to cover the joints and nail holes in drywall before it can be sanded to a smooth finish. It typically takes a day or so to dry, but fast-setting mixes are available that take just a few hours to harden.
Use a quality knife, such as Hyde Tools’ 6-Inch Flexible Black & Silver Stainless Steel Joint Knife to apply the mud over each joint. A good knife will distribute the mud evenly and provide you with a smooth, consistent finish. After applying mud to the entire length of a single vertical joint, position a strip of paper tape about two inches shorter than the joint over it. Pull the joint knife smoothly to bed the tape securely in the mud and make sure that it is fully covered. Repeat this process with all vertical joints in the wall.
Next, you will need to spread a thin second coat of mud over the tape and nails. This is important, because it will protect the tape from damage and ensure that any future drywall coatings will adhere to it. Make sure to spread enough mud to completely fill the corner bead pockets; otherwise, air and structural settling may cause these pockets to shrink or depress over time.
Fill the Gaps
When it comes to drywall, the skill required goes beyond brute strength. Finishing a new home or remodeling an existing home with drywall takes finesse and patience. It also requires a few tools like a small and large drywall knife, swivel-head pole sander and premixed joint compound (or “drywall mud”).
Before you start to tape and mud your drywall, be sure that the gap between your floor and wall is not caused by water leaks in your plumbing lines. If it is, you should hire a professional building inspector to inspect the gap and identify its source. It could be a sign of a serious foundation problem and should be corrected as soon as possible to prevent major damage to your home structure.
A few tips to help you make the mud job as smooth as possible:
If the first board doesn’t fit perfectly against the ceiling or wall, trim it to ensure that it fits tightly. However, don’t push the boards together too tightly. Forcing them too closely can cause them to break and crumble.
Use a level to measure where the next piece will be cut. You can either make all your cuts before beginning the project to save time and money, or you can cut each board as you work. The latter method results in less waste, but can take more time.
When constructing your outside corners, be sure to use a special drywall corner bead. This bead creates an outer edge on the corners of your drywall that makes it look more professional and attractive. It can be purchased at most home improvement stores, but it is usually much cheaper if bought online.
Apply the First Coat
Getting the drywall ready for painting or wallpaper requires a little finesse. You’ll need a few tools, including a small and large drywall knife, a swivel head pole sander, and premixed joint compound (or “mud”). The mud is mixed with water and you can add more or less to adjust the consistency.
First, apply a thin coat of mud to the entire wall. Roll the mud onto the surface with a roller, using down and side strokes to create an even coat. Keep in mind, it won’t be perfectly smooth at this point but the first coat should cover any raised surfaces and fill in the seams.
After the first coat, use your drywall knife to cut away the excess. Be careful to avoid cutting into the tape.
Next, apply a second coat. This time, you can apply the mud over the tape but not into the tape. For this coat, apply a thicker layer and be sure to get around all screw heads.
If you’re working on a long stretch of wall, you may want to consider using a bucket and trowel. It saves time and effort but you’ll need to be more careful to not overdo the mud.
It’s best to minimize the number of “butt” joints in your drywall. Long, tapered edges will meet more easily and make a better seal. If you have to have butt joints, apply a thin, generous layer of joint compound to both sides and then press the paper tape over it. This will help the mud adhere to the tape and create a good seam. Be sure to cover all of the tape on the inside and outside corners.
Apply the Second Coat of Mud
As the first coat dries, apply another very thin coat of mud over it. You’ll want to be sure your knife is still wiped clean of excess mud. It’s important that the second coat of mud go right over the tape, not just the wall. This will help keep the tape stuck and allow you to hide any humps under it with the final, very thin layer of mud that comes last.
On inside corners, fold a strip of pre-creased paper tape into place and smooth it in the mud with your 6-inch taping knife or an inside corner taping tool that features a preformed 90-degree shape for easy bedding. Make sure to use light stroking movements so you don’t dislodge the tape. It’s not unusual for the mud swath on butt joints to be 2 feet wide or wider, so don’t worry about it being too thick, just do your best.
You should also repeat the process with the 10-inch knife on screw indentations, beveled joints, and inside and outside corners. Once the mud dries, knock down any ridges with 100-120 grit sandpaper and lightly sand again. This will prepare the surface for painting and will ensure your drywall looks seamless.
Note that it takes a long time for drywall mud to dry, so be patient! The mud will look gray or splotchy when it’s wet, but will be white once it’s completely dry. Be sure to use fans and keep the area warm and dry so it can finish drying. It may take 24 hours or more, depending on geography and humidity. Using a fan to blow air across the surface can speed up the process, but be careful not to force it.
Apply the Final Coat of Mud
Once the first coat of mud is completely dry, apply a final thin layer, called the skim coat, to smooth out the drywall surfaces and fill any remaining gaps. Ideally, the surface should be nearly invisible to the eye. This final coat will prepare the walls for paint or a textured finish.
When applying the skim coat, be sure to keep it away from the seams. This will help prevent future cracking. Also, be careful not to get the mud too wet. If the mud is too wet, it will take longer to dry and can create unsightly rock-like ridges that are difficult to sand.
To speed up the drying process, use a fan to move air around the room. Avoid using extra heat, however, as it can cause the mud to set too quickly and result in cracked areas down the line.
It’s important to note that not all drywall mud is the same. There are different types of mud available for specific applications, such as all-purpose compound for taping and bedding, topping compound for the final skim coat, and spackling for small patching or repairing divots or holes.
For example, spackling is denser and harder when dry than all-purpose drywall compound, which is why it’s perfect for smaller patching jobs. The same goes for the sanding process: Some types of sanding compounds harden into rock-like ridges that are difficult and time consuming to smooth out, while others easily sand to a smooth finish. Choose an easy-to-sand setting mud to save time and effort in the long run. Topping and finishing mud are also available, which are slightly softer and designed to be more durable than tape-and-bed compound.