Drywalling has a bad name. Show me someone with a tub of mud on one hand, and they will inevitably envision the living room in which there will be absolutely nowhere that a fine layer of white powder can’t reach.
I understand. It’s messy.
However, the fact of the matter is that drywall repair and installation isn’t wizardry. It’s not something that requires a special degree from any fancy college. It’s a mechanical process – cut, screw, tape, cover in mud, sand. If you skip steps, it will show; take the right amount of time to do everything properly and you will end up with even a giant hole filled perfectly.
In this tutorial I will teach you how to put walls together in all sorts of situations. I don’t have all the technical terms down yet, but no matter whether you want to fill a hole for a doorknob or put new Gyproc up in a cold Canadian basement, this is how to do it.
Buying Materials: What Actually Works
Before anything gets sliced off, one needs the appropriate supplies. Entering a store like Home Depot or Rona can seem overwhelming when there are twenty varieties of mud and tape.
The important parts are listed below.
The Drywall: Standard interior walls take 1/2-inch thick drywall. Ceilings usually get 1/2-inch or 5/8-inch. If you are doing a bathroom or somewhere wet, you buy the green board (moisture-resistant). If you live in Canada and you are boarding an exterior wall, make sure your vapor barrier (poly) and insulation are perfectly sealed before you ever put a board up.
The Mud (Joint Compound): You have two choices. Pre-mixed mud comes in a bucket. It dries slowly by evaporating water. Setting-type compound comes in a bag as a powder. You mix it with water, and it hardens via a chemical reaction in 20, 45, or 90 minutes.
My take on this? Beginners should mostly use pre-mixed mud for finishing. It gives you time to work. But if you are filling a deep hole, you need the bagged setting-type mud (like Sheetrock 90). Pre-mixed mud shrinks and cracks if you put it on too thick.
The Tools:
- A utility knife with fresh blades.
- A drywall saw (looks like a serrated dagger).
- A 6-inch and a 10-inch taping knife.
- A drywall screw gun or a drill with a dimpler bit.
- Fine-grit sanding sponges.
How to Install Drywall From Scratch
If you are framing out a new room, installing the drywall is actually the fast part. Mudding is what takes days.
Cutting and Snapping
You do not use a saw to cut drywall unless you are making a space for installing a window or an electrical outlet. The drywall is scored and snapped off.
Measure your cuts. Using a utility knife and a T-square, score a line along the paper on the front side of the sheet. You need not go deep into the chalky interior; just through the layer of paper is fine.
Once the drywall sheet is scored, turn it over and snap it back from the cut line. The sheet will snap right where you want it, in a straight line. Now, just use your knife again along the backside crease.
Hanging and Fastening
Always install the sheets on the wall horizontally, not vertically, as it makes the joint easily accessible for taping and mudding.
Press the sheet tightly against the frame structure. Screw the sheet every 12 to 16 inches in the studs.
This is where everybody goes wrong. The screw should be inserted just below the paper surface. However, and here comes the kicker, it should never penetrate the brown paper layer. Once the screw tears the brown paper layer, it loses all its strength and becomes useless. Remove the screw and reinsert a new one inch away. Purchase a special bit called the “dimpler.” It ensures the screw is inserted to the right depth. This inexpensive tool saves many hours of frustration.
DIY Drywall Repair: Fixing the Messes
This is why people usually end up searching for assistance. Life occurs. Your kids will throw their toys around, someone will slam a door too violently, or the plumber will cut large squares into your ceiling to patch a broken pipe.
Drywall repair depends on the magnitude of the issue. Not all techniques are applicable for repairing a nail hole or a hole as big as your boot.
Tiny Dents and Nail Holes
Once you remove the picture hook from the wall, there is no need for the tape.
Use the blade end of the putty knife to apply pressure on the hole so that it collapses. Make sure that there is a small depression. Using your 6-inch putty knife, take a little spackle or drywall compound and spread it across the hole, pressing down.
Wait for about an hour. In case it has shrunk, repeat the process. Once done, sand, prime, and paint.
Doorknob Damage (The Mid-Size Hole)
For the fist-sized hole or even the doorknob-sized hole, one needs a bridge. Mud cannot be used to fill an empty hole as it will fall straight through the gap inside the wall.
Make what is called a California Patch.
Cut out a square from a piece of scrap drywall material two inches bigger than your hole on all sides. Turn the piece over. Score the backside paper the same size as your hole. Break the drywall along the lines and remove the core, but keep the front piece intact in the center.
Thus you have the drywall plug with a two-inch paper border.
Apply a ring of mud along the perimeter of the hole. Push the plug into the hole. Using the knife, compress the paper border against the wall and squeeze out extra mud. Here comes the paper tape. Once dried, apply another coating of mud over the patch.
Massive Holes and Water Damage
The paper patch will not withstand in case there is a water leak or an individual falls into the wall. It calls for rebuilding the construction.
Using the utility knife or a drywall saw, cut off the damaged drywall. In this way, you will create a rectangle opening that would give access to at least half of the studs on either side of the wall.
In case you cannot see the studs from the other side, there is a necessity to make some backing. In this way, two boards should be made out of spare wood (plywood or 1×2 lumber will do). Slide them into the wall opening and screw them to the studs of the wall on the other side of the hole.
Cut the new piece of drywall to fit the newly created rectangle. Fix the new piece of drywall with screws to the new backing board. In such a way, it becomes necessary to install a new piece of drywall.
Fixing Cracks and Ceiling Nightmares
Ceilings are awful to work on. Gravity fights you the entire time, and the dust falls right into your eyes. Wear safety glasses. Seriously.
Stress Cracks
In case there is an irregular crack down the wall or across the ceiling, covering the crack with paint will not help. The crack will appear again in a month because houses have to be moved. Wooden frames expand and contract in response to changing temperature conditions, especially Canadian winters.
For cracks to be corrected, you need to excavate them. Use the tip of your utility knife to cut along the length of the crack into a v-notch pattern. This is intentional. Clear the dirt in the crack, fill it with mud and apply the paper tape across the v-notch smoothly.
Truss Uplift
If you spot a crack exactly at the meeting point between your ceiling and your internal wall, then it is probably due to truss uplift. During winter months, trusses in your attic bend upwards, thus separating your ceiling drywall from the wall.
What do you need to do to solve the problem? Do not attach your ceiling drywall too close to the wall. It should float around the edges with wallboards pushing against the ceiling. In case you have a crack in your ceiling, you can put crown molding on the ceiling alone.
Mudding and Taping: Where Things Go Wrong
This is where you distinguish between a quality wall surface and a rough patch job. It’s not about building an elevation on the crack when you mud. It’s all about feathering it out to the point that your naked eye won’t see any bump.
Paper Tape vs. Mesh Tape
The reason why most people go for mesh tape is that it is adhesive; therefore, no need for any mud before taping the seam. Just apply the tape and cover it with some mud.
Wait, actually forget it – the mesh tape comes with an enormous disadvantage. The thing is that it is less strong compared to the paper tape; thus, applying mesh tape together with regular mud can result in cracking of joints. You have to use the mesh tape only with the powder type of mud compound.
When using the usual pre-mixed mud, you should use the paper tape instead.
Apply the thin layer of mud onto the seam first. Then you apply the tape on top of the mud and run the six-inch blade tightly over the tape, expelling all excess mud out. Make sure you do not squeeze the mud out too much – otherwise, you will end up with bubbles.
The Three-Coat Rule
Good drywall repair requires at least three coats.
Coat 1: The Taping Coat. Embedding the tape. Keep it narrow. Let it dry completely.
Coat 2: The Fill Coat. Switch to a 10-inch knife. Apply mud over the tape, extending a few inches past the edges of the first coat. The trick here is pressure. Put pressure on the edge of the knife blade that is touching the bare wall to squeeze the mud down to zero thickness. Leave the middle a bit thicker.
Coat 3: The Finish Coat. This is a very thin skim coat. You are just filling in tiny air bubbles and knife marks. Extend the edges even wider.
What usually happens is people slop a massive amount of mud on the wall in one go, thinking they’ll just sand it flat later. That is a terrible idea. It will take three days to dry, it will shrink, and you will spend six hours sanding. Apply thin coats.
Sanding Without Ruining Your House
The finishing touch is sanding.
Use a high-gloss sanding sponge. Make sure to turn off your heating and cooling systems prior to sanding. You don’t want the HVAC system sucking up the gypsum dust from your patch and circulating it throughout your home. Cover doorway openings with plastic sheeting.
Use either a work lamp or a flashlight for this process. Press the light flush against the wall, illuminating your patch at an angle. The shadows cast by the light will make all irregularities evident.
Apply gentle circular strokes when sanding. Concentrate your efforts on the area where the mud and wall meet. It must be perfectly smooth. Avoid over-sanding the center of your patch or you will bring your tape work to the surface.
If dust bothers you, consider the process of wet sanding. All you need is a large grouting sponge that needs to be dampened, but not soaked. Then carefully rub it against the edges of the dried out mud, and voilà – there will be no dust at all. It takes some effort and some practice, but if you want to repair something in a finished room, it’s an invaluable technique.
The wall needs to be touched by your fingers and when it seems to be smooth, just wipe it off with a dry microfiber rag.
Apply primer. Paint it. And leave it be.
Yes, nobody likes drywalling. But if you work calmly and do everything as you were told, you wouldn’t need a specialist to repair a hole on your wall.