How to Fix and Finish Drywall (with Pictures)

2024 Author: Samantha Chapman | [email protected]. Last modified: 2023-12-17 09:13

Most of the walls and ceilings created by modern construction are plasterboard, or drywall, a plaster-like material sealed between two sheets of thick cardboard and fixed with special screws. Each plasterboard panel has rounded corners to allow you to fix it without imperfections. This article will teach you how to fix it and putty it. It is a work that is divided into several phases and that requires specific tools.

Steps

Part 1 of 6: Prepare the drywall

Step 1. Make sure that the drywall is fixed to the supporting beams of the wall correctly

Usually the panels are fixed to all the load-bearing wall beams they cover, every 15-20 cm. In theory, in a wall divided into sections of 60 cm from the center, the plasterboard should be supported at the edges every 20-30 cm with five screws; in the most common walls that have load-bearing beams every 40 cm from the center, you should insert a row of screws on each edge as well as two other screws 40 cm from the edges.

• Drywall nail guns are very simple to use and allow for quick work. They do not create confusion and residues like the drill or the electric screwdriver. Borrow one or buy a specific countersink that you can attach to your drill. This tool allows the precise seating of each screw that you need to insert.

• Make sure that the screws are countersunk correctly, they must wrinkle the paper covering the plasterboard without tearing it.

  

• Run the drywall trowel blade along the screw heads to make sure they don't stick out. Remove, countersink or adjust any screws that stick out even just a little (this step will save you a lot of hassle and frustration in the final step and you won't have to remove the screws once the filler is applied).
• Don't use nails unless you want to borrow a drywall nail gun. There is a high chance of deforming the screws or hitting the drywall and smashing it with the hammer. If you loosen the nails incorrectly, you will make a huge hole in the wall. If you have decided to use the nails anyway, put them in pairs, spaced about 4 cm apart and always deal one more blow when you put the second one.

Step 2. Minimize the "seams"

The long edges of the drywall are beveled; the short ones (and any edges you want to cut) are not, so you will have some problems in the finishing phase. In addition, the panels must coincide with the beveled edges as precisely as possible, there must be no gaps greater than 3-6 mm (check that the corners also coincide, but in this case do not worry too much if there are larger gaps, up to when each panel is firmly fixed; any space between the corners can be filled with joint putty).

Step 3. Schedule an inspection if needed

If the building regulations of your municipality require it, you must make an appointment with the experts of the Technical Office for an inspection. It is better to endure the hassle of a scheduled check-up than having to demolish the wall after it is taped and grouted.

Part 2 of 6: Apply the First Layer

Step 1. Know that you will have to apply many layers

The goal of each hand is to make a smooth and flat surface. For the first layer:

• On the inside corners: slide the edge of the putty knife firmly against the tape on one side and against the plasterboard on the other.
• On non-taped seams: Use drywall as a guide for both edges, leaving a concave curve.
• On taped seams: do the same.

Step 2. Get the right filler

You can buy a dry product (to which just add water) or a mixture already mixed. Both solutions are available in a variety of mixes such as easy-to-sand light ones, quick-set ones or regular ones.

• Dry putty is cheaper and you can only prepare the amount you need (even just to be able to try it out and figure out how long it takes to solidify). Use it to fill in large holes and crevices. This product turns out to be a bit complicated to spread on large surfaces, it is not easy to sand, to smooth and takes a long time offering a mediocre result. However, it has the advantage of stabilizing by chemical reaction (although drying times may vary, which is why you should always read the directions on the package), so it can be re-applied in a short time.
• The pre-mixed fillers are ready to use immediately after a quick stir in the bucket. However, they are a little more expensive, plus they are sold in large packages, in much larger quantities than you can use.

Step 3. Get enough putty for the job you need to do

As a rough estimate, calculate 4 liters of stucco for every 9 square meters of plasterboard.

• On the market you can find many brands and many consistencies of putty. You can use a "universal" one for the base (first coat), to stabilize the wall and hide the tape, while a lighter product is appropriate for the final layer. You can also rely on a brown putty also called finishing; it is a beige colored compound that becomes very light when it dries, it has a more plastic consistency than normal grout. It becomes smoother and has a lesser tendency to bubble. It is usually used in the last hand.
• In pre-mixed grouts there is always an aqueous layer on the surface, just mix them slowly with a mixer drill and a 1.3 cm spatula tip. Continue to work the mixture until it becomes homogeneous and the water is absorbed, there should be no lumps. Do not use a high speed as air bubbles will form in the grout.

Step 4. Get the right trowel

The plastic ones have a tendency to ruin along the edges leaving tiny filament-like fragments; It is therefore vital that you check your tools regularly to make sure they are always in top condition. You will need a 12.5-15cm spatula, one 25cm and another 35cm. For hard-to-reach spots, get a narrow-tipped putty knife (or two). A tray for mixing the putty also comes in very handy.

• If your tools are new, smooth the sharp edges slightly.

• Trowels and steel containers can rust, so clean them thoroughly at the end of each work session and dry them thoroughly.

  

  Step 5. Apply the first layer of putty

  Before starting, you need to mix a little water with the grout, it is important that the first coat is slightly more watery than the following ones. Aim for a slightly more watery consistency of the grout than that of the cream. Use the 12 or 16 cm trowel and take about 5 cm of putty.

  • On the joints between the panels, put as much grout as you want, taking care to press it well. You can scrape off the excess compound later, so don't worry about it being smooth now. For this layer it is better not to skimp with the putty.
  • You just need to make sure you press a lot of putty into each gap to create a smooth, even surface.
  • The beveled edge (the long one) of each drywall panel shrinks about 6.5cm from the edge, which means you need to cover the seam between the two by at least 13cm.
  • With the help of a very bright light, arrange it diagonally to the wall so as to identify each area that needs to be covered.
  • When using large trowels to cast putty on the wall, remember that you should hold them at a 45 ° angle to the wall. As you drag the mixture onto the wall, tilt the angle more and more until the trowel blade is almost parallel.

  

  Step 6. Once all the cracks are filled, apply a first coat over the newly grouted areas to smooth them out

  Prepare the seams to be taped but do not remove too much grout, otherwise they will be dry and / or too thin (think of the first layer of grout as glue to which the tape must adhere; if it dries, it becomes unusable. more work to fix, when you thought you were done already. So don't apply more putty than you can tape over before it dries).

  

  Step 7. Cut the paper tape to size

  It must be as long as the seam, plus a few extra inches at each end.

  • Some recommend soaking it in water. While this makes things a little easier, be aware that they increase the chances of getting dirty in the room, as well as the fact that the tape gets much weaker.
  • On the other hand, wetting the tape prevents air bubbles from forming under it, saving you the trouble of having to go through it again to get rid of them. The choice is yours alone.

  

  Step 8. Apply tape to the seams

  Press it on the newly grouted areas starting from one corner and moving towards the opposite one. Try to center the tape as precisely and evenly as possible, covering the contiguous edges of two panels equally. The tape should be slightly sunken in the center.

  

  Step 9. Secure the tape with the trowel

  Start in the middle of the joint, hold the trowel at a 25 ° angle to the wall and press the tape firmly to make it stick to the compound. Drag the spatula along the joint, downwards, with a firm and continuous motion to smooth the tape.

  • If the ribbon curls, move it away from the wall or flatten it with your other hand.
  • Repeat the same process but from the middle of the joint upwards, up to the ceiling.
  • If there are bubbles, make incisions. The tape will not adhere to the wall where the grout is dry. Take a craft knife and cut the tape over the bubbles and put some putty back on (if you don't get rid of the bubbles you will end up with a horrible result). Smooth out the notch left by the tape with fresh putty.

  

  Step 10. Put the tape on the inside corners

  Use the 12 cm trowel and cover the joints for at least 5 cm on each side using putty. Cut the ribbon to the right length and fold it in half along the center sunken line. Press it into the corner and mash it with the trowel.

  • Always start from half the length of the tape and smooth it with the trowel moving downwards. Then move on to the top half, towards the ceiling. Make sure the core is well covered and smooth.
  • Line one side of the corner tape with a thin layer of putty.
  • Do not apply too much pressure with the trowel blade. Even if you try not to use the sharp edge of the tool, there is always a risk of cutting the tape. The trowel can slide naturally into corners and excessive pressure is not needed.

  

  Step 11. Cover the outer corners

  The angular profiles make the edges more resistant because they protect them from bumps and blows. Fix a metal profile on the external corners with nails spaced 25 cm apart; be very careful to perfectly center the profile, otherwise it will be impossible for you to cover it evenly with putty.

  • Use a 12.5cm trowel and apply a layer of putty to one side of the corner profile, smoothing it out. To get the right angle, place one side of the trowel blade against the profile and the other side against the plasterboard. Smooth out the grout with just a few strokes. Repeat the process on the other side.
  • Alternatively, you can apply putty and adhere a paper corner profile just like you did with the tape in the inside corners. The procedure is practically identical: instead of nailing the profile, 'glue' it with putty and then remove the excess compound with the trowel.

  

  Step 12. Fill the screw holes with putty and smooth the surface

  Apply a little over the head of each screw or nail and then wipe off the excess with a small trowel. Be sure not to leave out any hollows created by the screws without leaving excess grout.

  

  Step 13. Wrap the wall for the night

  Check that all joints are well covered with putty and tape, clean tools, close the compost bucket and let it pass overnight.

  Part 3 of 6: Sand the First Layer

  

  Step 1. Make sure the first coat is completely dry, especially in the inner corners close to the ceiling

  When the grout is still wet it has a darker color, tending to gray, when it is dry it should be white. Depending on the climate and humidity level in your area, it may take 6 to 8 hours for complete drying. In colder and humid areas it can even reach 24 hours, so equip yourself with fans and heaters.

  

  Step 2. Wear a dust mask every time you sand

  This operation releases a lot of white dust into the air that you don't have to breathe. If you work near furniture or the kitchen (or anything else that you don't want to get dirty with fine white powder), cover the surrounding areas with plastic sheets and also seal every door to the room with them. A little preparatory work will save you from intense cleaning work.

  

  Step 3. Tap the wall

  With a large trowel, gently tap any excess grout or imperfections from the tape and screws. A light scraping is enough. This trick makes sanding easier and more effective.

  

  Step 4. If the surface is smooth and there are no lumps, holes or imperfections, then there is no need to sandpaper

  If not, lightly sand the joints. Use medium-grit sandpaper and mount it on a sanding rod. Smooth out rough areas and pay special attention to the edges. Apply even, gentle pressure. Do not completely sand the thickness of the putty or the paper tape, only work on the edges.

  • Unless the surface is really very rough, avoid sanding and simply sand. An electric grinder creates a suffocating cloud of dust and will likely tear the paper tape off the wall. In addition, drywall dust shortens the life of the sander itself.
  • Sand the corners with a suitable block, be very careful on the corner joints.

  Part 4 of 6: Applying the Next Layers

  

  Step 1. Use the 25cm trowel for the following steps

  Apply a thicker layer of putty to all seams and all screw heads. You must use a compound with a normal density for the second layer and all those that follow. The grout should not be watery as before.

  • Smooth the mixture with a second pass. Apply it with downward movements and then smooth it with horizontal movements.
  • The goal of this second coat is to fill in every bevel in the drywall, so grab the trowel so that the edge is at 90 ° with the wall, there should be no gaps between its blade and the seams of the panels.

  

  Step 2. Shave the edges again if necessary

  To do this, smooth the outer edges by adding more filler above and below each joint.

  • On the corner joints, cover the other side of the tape (the one you left bare after the first coat) with a thin layer of putty using the wall and the corner itself as a guide.
  • On the straight seams, add putty on both sides of the tape and smooth the edges with the trowel.

  • As you proceed with the subsequent layers of compound, the thickness increases.

    

    Step 3. Let it dry overnight

    Again, you must allow the grout all the time it takes to dry before proceeding with the next layers.

    

    Step 4. Repeat the same steps

    Lightly scrape the wall with the trowel and then sand. Remove any coarse imperfections with the trowel blade and then finish with fine-grained sandpaper, the outer edges should be smooth.

    

    Step 5. Make sure the grout is dry

    When you're ready to apply the third coat, try to even out the edges as much as possible with the rest of the wall. Your goal is to thicken the joints by adding putty. This will make them more resistant and they will conform better to the rest of the wall making them invisible.

    • When applying the third coat, repeat the same process but use a larger trowel. The 30 cm one will make the work much faster than the 15 cm one.
    • Let it dry overnight. The next morning, sand the surface again and make sure it is smooth, seamless and even.
    • Check the wall with a light, if it reveals any imperfections near the ceiling, if there are points where the first layer is thicker or the seams are visible, then you will have to apply a fourth coat of putty.

    Part 5 of 6: Finishing the drywall

    

    Step 1. Learn how to finish drywall

    Tape and grouting the wall are just the beginning of the job, whether you're doing a repair or erecting a new wall. The finishing prepares the plasterboard for the application of the primer and the paint.

    

    Step 2. Create a light texture on the drywall if desired

    If you want the wall to be finished with stucco, rough or with some geometric shape, know that you can do it, you just have to learn how.

    

    Step 3. Apply primer and paint the wall

    To have a beautiful wall, you must first apply the primer. This is often a neglected but absolutely essential step!

    Part 6 of 6: Learn more

    

    Step 1. Learn about drywall

    The panels are available in various shapes, sizes, types and thicknesses. For a standard wall usually 1, 2 cm or 1, 5 cm thick sheets with dimensions of 120x240 cm or 120x360 cm are used. On the market there are all kinds of products such as "green boards" that resist humidity and are covered with recycled paper. They are often used in rooms where the humidity is higher (bathroom and kitchen). The ceiling panels are called "CVs" and have no tendency to sag; they are larger than standard panels because they are designed to cover larger surfaces.

    • The ceilings and walls are usually lined with 1.3 cm thick plasterboard. For the ceilings the product "CV" is used. There are also particularly light materials designed for this purpose.
    • In some cases it may be necessary to use panels with a thickness of 1.6 cm for both the ceilings and the external walls. They are "fireproof" materials (also called "TypeX") because they resist fire for a longer time than standard 1.3 cm panels. In some municipalities it is allowed to apply two plasterboard panels in areas at risk of fire instead of mounting a more expensive material.
    • The 1.6 cm panels are also useful for reducing noise, thanks to their mass. Recording studios often resort to a double layer of 1.6 cm plasterboard.

    

    Step 2. Know where not to erect drywall walls

    It should not be applied to circumscribe the shower area or the bathtub. In this case you have to use concrete coupled with the right insulation material.

    • Also use the correct tape if you need to seal the wall from water or noise. The joints between the concrete walls must be finished with a fiberglass mesh fixed with a specific putty or tile glue.
    • Contact your Municipality's Technical Office to find out about the building laws and regulations in your area.

    

    Step 3. Handle drywall properly

    It is a light and thin material, until you lift it! When you work it on the ground to cut it, move it and lift it it takes some kind of effort, but when you have to install it on the ceiling it is something else entirely.

    You can keep the plasterboard in the ceiling with 5x10 cm pieces of wood nailed in a “T” shape. Secure them under the drywall to hold it against the ceiling and then insert some screws to secure it. However, if you have to install drywall yourself or feel you are not strong enough to do it, it is worth hiring a lift cart

    Advice

    • Use a vacuum cleaner to clean after attaching a hose to the blowing end.
    • Brighten your work area to avoid blemishes.
    • Keep the bucket clean by moving the putty from the edges towards the center. It is a compound that tends to dry out quickly, forming lumps that can leave imperfections on the plasterboard.
    • Take your time. It will take between two and five coats of putty to finish. This also depends on your experience. Furthermore, each application must be left to dry completely.
    • Cover the vertical seams before the horizontal ones. The horizontal ones will eventually cover the ends of the vertical ones.
    • Don't use fiberglass tape - it's expensive and joints break easily.
    • When the grout has dried, do not sand. Use a clean trowel to remove any lumps and bubbles.

    Warnings

    • Before drying, the grout is soluble in water, so it immediately eliminates any stains. On carpets, however, it is better to let it dry and then remove it.
    • Prevent dry putty from getting into the product bucket, or it will cause trouble. If you see lumps, remove them with your fingers or trowel before they dry. Otherwise, you'll have to sand them down and start over.
    • Do not use tile glue. The putty must not have any sticky consistency.
    • Do not dilute or modify the grout. While it is possible to do this, in most cases it is not necessary.
    • Use only plastic, wire mesh or plasterboard tape, depending on the application. These types of tapes are not easy to work with and may require three or four coats of putty (or more). If you have to work in an outer or inner corner, for example, wire mesh tape is not ideal, as it will not bend. If you are carefully spreading the grout, you can use metal tape on the joints that have two or three layers, although it will take a lot longer to finish perfectly.