When it comes to painting a room, one of the most important steps is preparing the walls. This includes sanding them down to create a smooth surface that the paint can adhere to. However, choosing the right grit sandpaper can be confusing, especially if you’re not familiar with the different options available. In this article, I will share my knowledge and experience to help you determine what grit sandpaper to use for painted walls. 
The first thing to consider is the condition of your walls. If they are in good shape, with only minor imperfections, you can use a fine grit sandpaper, such as 120-grit. This will smooth out any rough spots and create a surface that is ready for paint. However, if your walls have significant damage, such as peeling paint or deep scratches, you will need to use a coarser grit sandpaper to remove the damaged areas. A medium grit sandpaper, such as 80-grit, is a good choice for this type of job. Another factor to consider is the type of paint on your walls. If you’re painting over a glossy or high-gloss paint, you will need to use a fine grit sandpaper to dull the surface and create a better bond for the new paint. However, if you’re painting over a water-based paint, a medium grit sandpaper will be sufficient to smooth out any imperfections. It’s important to note that if you’re painting over an oil-based paint, you should use a coarser grit sandpaper to remove the glossy surface and create a better bond for the new paint.
Understanding Sandpaper Grit
https://www.youtube.com/watch?v=icUjk_1qpOA&embed=true When it comes to sanding painted walls, choosing the right sandpaper grit is crucial to achieving a smooth, even surface. Sandpaper grit is categorized into grades based on the size of the abrasive particles. The lower the grit number, the coarser the abrasive particles, and the higher the grit number, the finer the abrasive particles. For a comprehensive guide on choosing the right abrasive, check out this article on what grit sandpaper for primer before paint. Here are some tips to help you understand sandpaper grit and choose the right one for your painted walls:
Coarse Grit Sandpaper
Coarse grit sandpaper, such as 60-grit or 80-grit, is ideal for removing old paint, roughing up a surface, or smoothing out a rough patch. This type of sandpaper is too abrasive for finishing work and can leave deep scratches on the surface.
Medium Grit Sandpaper
Medium grit sandpaper, such as 120-grit or 150-grit, is suitable for smoothing out rough surfaces and removing small imperfections. It is also ideal for preparing surfaces for painting or staining.
Fine Grit Sandpaper
Fine grit sandpaper, such as 220-grit or 240-grit, is perfect for finishing work and preparing surfaces for a final coat of paint or varnish. It removes small scratches, blemishes, and imperfections, leaving a smooth, even surface.
Extra Fine Grit Sandpaper
Extra fine grit sandpaper, such as 320-grit or 400-grit, is used for the final sanding before applying a topcoat. It removes any remaining imperfections and creates a smooth, flawless surface. It’s essential to choose the right sandpaper grit for your project to avoid damaging the surface or spending unnecessary time sanding. Remember to start with a coarse grit sandpaper and gradually work your way up to a finer grit for the best results.
Choosing the Right Grit for Painted Walls
https://www.youtube.com/watch?v=KiE4Pk_gu50&embed=true When it comes to sanding painted walls, choosing the right grit sandpaper is crucial to achieving the desired result. Here are some guidelines to help you choose the right grit for your project:
Low Grit Sandpaper
Low grit sandpaper, such as 80 or 100 grit, is best for removing thick layers of paint or smoothing out rough surfaces. This grit is also useful for removing small imperfections, such as bumps or ridges, on the wall’s surface. However, be careful not to sand too aggressively, as this can damage the wall’s surface.
Medium Grit Sandpaper
Medium grit sandpaper, such as 120 or 150 grit, is ideal for preparing the wall’s surface for a new coat of paint. This grit can remove any remaining paint or rough spots left by the low grit sandpaper. It’s also useful for smoothing out any areas where the paint may have peeled or bubbled.
High Grit Sandpaper
High grit sandpaper, such as 220 or 320 grit, is best for achieving a smooth finish on the wall’s surface. This grit is perfect for sanding between coats of paint to remove any brush strokes or imperfections. It’s also useful for sanding down any high spots left by the medium grit sandpaper. When sanding painted walls, it’s important to use a sanding block or pad to ensure even sanding across the entire surface. Always wear protective gear, such as goggles and a dust mask, to protect yourself from dust and debris. In summary, choosing the right grit sandpaper for painted walls is crucial to achieving a smooth and even finish. Low grit sandpaper is best for removing thick layers of paint, medium grit sandpaper is ideal for preparing the surface, and high grit sandpaper is perfect for achieving a smooth finish. Always use a sanding block or pad and wear protective gear when sanding painted walls.
Precautions When Sanding Painted Walls
Safety Measures
When sanding painted walls, it is important to take the necessary safety measures to protect yourself. Here are some precautions to keep in mind:
- Wear a dust mask to prevent inhaling dust particles.
- Use safety goggles to protect your eyes from flying debris.
- Wear gloves to protect your hands from the abrasive sandpaper.
- Work in a well-ventilated area to avoid breathing in harmful fumes.
Avoiding Damage
Sanding painted walls can be a delicate process, and it is important to avoid damaging the surface. Here are some tips to help you avoid damaging the painted walls:
- Use a fine-grit sandpaper to avoid scratching or damaging the surface.
- Sand gently and in a circular motion to avoid creating uneven spots.
- Avoid using too much pressure when sanding to prevent creating divots or dents in the surface.
- Always test a small, inconspicuous area before sanding the entire wall to ensure there is no damage to the paint or wall surface.
By following these precautions and tips, you can safely and effectively sand painted walls without causing any damage. Remember to always work carefully and take your time to achieve the best results.
Additional Tips for Sanding Painted Walls
When sanding painted walls, it’s important to follow some additional tips to ensure a flawless finish. Here are some tips I’ve found helpful:
- Use a sanding block: Using a sanding block can help you apply even pressure to the wall, preventing uneven sanding and damage to the surface.
- Sand in a circular motion: Sanding in a circular motion can help you avoid creating visible sanding lines on the wall. Be sure to overlap each circle as you sand to ensure even coverage.
- Use a vacuum or tack cloth: After sanding, use a vacuum or tack cloth to remove any dust or debris from the wall. This will ensure that the surface is clean and ready for painting.
- Don’t oversand: Be careful not to oversand the surface of the wall, as this can damage the underlying surface and create visible scratches.
- Test a small area first: Before sanding the entire wall, test a small area to ensure that the sandpaper you’re using is the right grit for the job. If the sandpaper is too coarse, it can damage the surface of the wall, while sandpaper that is too fine can take longer to achieve a smooth surface.
By following these additional tips, you can ensure that your painted walls are properly prepared for repainting, with a smooth and flawless finish.
