How to Plaster a Ceiling

January 11, 2023
plaster ceiling

Plastering a ceiling can be daunting, especially if you’ve never done it before. Whether it’s a brand-new ceiling or a ceiling that needs repairs and patching, plastering can be a tricky process. But don’t worry, with this step by step guide to plastering a ceiling, you’ll be able to learn the basics and get the job done quickly and easily. 

We’ll cover all the key elements from preparing the surface to applying the plaster, as well as tips and tricks for a successful job. So if you’re ready to take on the challenge, grab your tools and let’s get started!

What is Ceiling Plaster?

Ceiling plaster is a building material used to finish the surface of a ceiling. It is also known as gypsum plaster, as it is created with gypsum, a naturally occurring mineral. Ceiling plaster is usually applied in two layers: An outer layer known as the finish coat and an inner layer known as the skim coat. 

The finish coat is the top layer of the plaster. This layer is the decorative finish, and the finish coat creates the look and texture of the ceiling. The finish coat is applied after the skim coat is applied. The skim coat is the base layer of the plaster. This layer provides strength and support to the finish coat. The finish and skim coats are applied when the ceiling is dry and ready for finishing.

Gather your tools and materials

Before you get started, make sure you have all the tools and materials you need. Here’s a quick list of what you will need:

  1. A putty knife and trowel - these are essential for applying the plaster.
  2. A hawk or a knee bolster (if you’re working on the ground) - to keep your materials in place and make mixing and measuring easier.
  3. A long wooden plank (or 2 shorter planks) - a long plank is ideal if you’re working on a scaffold or on the ground with a knee bolster. If you’re working on a stepladder, use 2 shorter planks.
  4. A sturdy ladder - if you’re on a scaffold, make sure it’s secure and not overloaded.
  5. A drop sheet - to protect the area underneath the ceiling and make clean-up easier.
  6. A dust sheet (optional) - to protect the area underneath the ceiling while you’re working.
  7. A bucket - to mix and store the plaster.
  8. A shovel - for shoveling out the laths.
  9. Trowels - for leveling the plaster.
  10. A hawk - for mixing the plaster.
  11. Plasterboard jointing tape - to seal the cracks between the ceiling and the wall.
  12. Jointing compound or a jointing trowel - for filling and smoothing any cracks or holes.
  13. A sanding block or something similar - to sand down any uneven areas. 
  14. A plastic bucket or other container - to collect the excess plaster and water.

Prepare the Surface

Removing any existing plaster

First, you need to remove any existing plaster or wallpaper. You can do this with a chisel or a scraper, but be sure to wear protective gear such as goggles and gloves. Once you’ve removed the plaster, make sure you clean the surface thoroughly with water. Make sure no loose bits of plaster remain, as these could cause problems during the process and may even lead to a messy finish.

Removing any old laths

If you’re working with an existing ceiling, you’ll most likely need to remove any old laths, as these will need to be replaced before you plaster. You can do this with a hammer or a chisel. If you’re working with a new ceiling, however, you don’t need to remove the laths, but make sure you seal the joints between the laths and the surface with a bonding agent.

Patching any holes or cracks

If you’re working with an existing ceiling and there are any holes or cracks in the surface, you need to patch these before you start plastering. You can do this with jointing compound (available in hardware stores) or a mix of sand, cement and water. Make sure you apply the mix in the right thickness, though, as it should be about 1/8” thick. You can also mix it in a bucket and apply it with a trowel. 

Make sure you smooth the mix thoroughly with a trowel and leave it to dry for a few hours. Leveling the surface with a skim: Once the holes and cracks have been patched, you need to level the surface with a skim. You can do this with a shovel or a float. Make sure you level the surface thinly and thoroughly, going over it several times.

Making sure the surface is dry

You need to make sure the surface is completely dry, as any water on the surface will cause problems with the plaster, such as cracking and bubbling. To be on the safe side, you can let the surface dry naturally for a couple of days, or you can use a hair dryer to speed things up.

Protecting the surface with a dust sheet

Once you’ve prepared the surface, you need to cover it with a dust sheet (also known as a drop sheet). This will protect the area underneath the ceiling while you’re working. Make sure you place the sheet close to the ceiling so there’s no danger of it falling down. You can secure it with a few hooks or nails. If you’re working on the ground, you can use your knee bolster to hold the sheet in place.

Cleaning the surface with a damp cloth

Before you start plastering, make sure you clean the surface thoroughly with a damp cloth or sponge. You need to remove any dust and dirt from the surface to make sure the plaster sticks properly.

Applying a bonding agent

Before you start plastering, you need to apply a bonding agent to the surface. Make sure the surface is clean and dry before you apply the agent. You can use a commercial bonding agent or a combination of 1 part cement, 1 part water and 1 part sand. This will help the plaster stick to the surface properly.

Applying a sealer

Finally, once you’ve applied the bonding agent, you need to apply a sealer to the surface. This will protect the surface and make it easier to clean. There are various types of sealers you can use, such as an external sealer or a wood sealer. Make sure you apply the sealer in a thin layer, as too much sealer can affect adhesion.

Smooth and level the plaster

Once you’ve applied the plaster, you need to smooth and level it. This will ensure the surface is even and will make it easier to sand down later. You can use a wooden float for this. Take your time when doing this and go over the surface thoroughly.

Tips for a successful job

  • Start your work on a dry day and make sure it stays dry throughout the job.
  • Make sure you wear protective gear such as goggles, gloves, a dust mask, and overalls/an apron.
  • Make sure you have enough lights to illuminate the whole surface.
  • Mix the plaster thoroughly, but not too much.
  • If you’re using a hawk to mix the plaster, wear gloves to protect your hands from the sharp edges.
  • Keep the surface covered with a dust sheet at all times. This will protect it from damage and make clean-up easier.
  • Avoid walking around on the surface as much as possible, as this can cause damage. If you need to move around, do so on boards or a ladder.
  • Make sure you clean up any mess as you go along to avoid leaving a big mess at the end.
  • Take your time and do the job properly. Rushing can lead to mistakes and sloppy work.
  • Don’t forget to take breaks. Standing at the same spot for long periods can be tiring, so make sure you take breaks to rest your legs and back.

Clean Up and Fix Any Mistakes

You’ll want to clean the surface of the ceiling thoroughly before applying the plaster. Remove all traces of dust, dirt, and old paint. Make sure the surface is completely dry before you start plastering. It’s best to wait at least a day after doing major repairs, or up to a week if you’re repainting the entire ceiling. 

Once the surface is clean and dry, you can apply the first coat of plaster to seal it and prevent it from becoming too wet. If you make a mistake or apply the plaster too aggressively, you can clean it up and fix the surface before adding a second coat.

Finishing Touches

When the plaster has set and hardness, you can apply a second coat or touch up the first coat. This will add texture to the surface. Lightly tap a trowel against the surface to make it rough, which will allow the paint or wallpaper to stick better. 

When you’re applying the second coat, make sure you apply it in the same direction as the first coat to avoid creating a bumpy texture. When the plaster is completely dry, it’s time to apply a finishing coat. Depending on the type of ceiling and your personal preference, you can choose between paint or wallpaper.

If you’re painting, you can apply the first coat as soon as the plaster is dry. If you’re applying wallpaper, wait for about a week to allow the plaster to fully dry and settle.

Maintenance and Aftercare

Keep in mind that ceiling plaster is only suitable for interior walls - it’s not suitable for exterior walls. If you’re plastering an interior wall, the plaster will need to be repainted every 5 to 8 years. It’s best to wait a few months before repainting the wall to allow the plaster enough time to fully cure. 

Ceiling plaster is fairly durable and won’t require regular maintenance, but in rare cases, it can develop cracks or start peeling off. If this happens, you can repair it with a fresh layer of plaster. If you notice any loose or peeling areas, scrape off the loose plaster and apply a new coat, making sure to smooth out the surface with a piece of wood and a trowel.

Troubleshooting Common Problems

If you’re dealing with a bumpy surface, you may need to sand the ceiling. Make sure you’re sanding in the same direction as the existing surface, or you may make the bumps worse. If you’re dealing with excess wetness, you may need to wait longer for the surface to dry. 

If you’re dealing with a bumpy surface after the plaster has dried, you may have sanded too aggressively. Try smoothing the surface with a piece of wood and a trowel. If you’re dealing with a cracked surface, you may have applied the plaster too aggressively. Scrape off the cracked plaster and apply a fresh coat.

Summing Up

If you’re looking for a durable and affordable way to finish a ceiling, plastering is the solution for you. With careful preparation and the right tools, you can quickly and easily turn a plain ceiling into a stunning feature wall. 

Although it can be challenging, plastering a ceiling is well worth the effort and will add great value to any room. With this step by step guide, you’ll be able to learn the basics and get the job done quickly and easily. 

Pristine Painters is New York's premier painting service, and we're happy to provide our services to the boroughs of Manhattan, the Bronx, Queens, and Brooklyn. The exteriors and interiors of homes and businesses can be painted by us, and we do it all at the lowest possible prices

No matter how challenging the task, we can handle it. If you work with us, you can rest assured that you will receive both excellent results and attentive care. Don't wait to get in touch with us!

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