To ensure the best possible finish, it's vital that you sand your walls before any painting project.
While sanding is not required for every paint project, rough spots on walls, whether they have been previously painted or not, need to be sanded before they are painted to ensure the paint goes on smoothly.
The initial condition of the surface will determine what exactly will happen if you don't sand before painting. A clean, smooth, not glossy surface will take paint well. However paint can feel rough, streak, peel, chip, or even not adhere if not sanded first.
After removing imperfections and filling in holes, the painter will sand all the walls to help achieve an even, smooth look. Depending on the condition of the walls, your painter might clean them after doing all of this.
Smooth any repairs, bumps, and nibs with a drywall pole sander. For smoother walls and better adhesion, some of our pros sand all previously painted walls regardless of the shape they're in.
You can get by with sanding only the areas that have been patched, but walls look much better after painting when you very lightly sand the entire wall. The point is to get rid of any little imperfections, not to remove roller texture, so this is a quick sanding. Use a sanding sponge with 100-grit sandpaper.
How much should you sand before painting? You don't need to sand too hard, just enough to scuff up the surface so the paint will adhere better. If you're sanding by hand, it shouldn't take more than probably 15 minutes to lightly scuff sand a large dresser. If you're using an electric sander, it'll go faster.
Yes, professional painters clean walls before painting. Cleaning and preparing the wall surface will ensure that your paint job lasts longer and looks better. This involves removing dust, dirt, and old paint chips, applying caulk or putty to cracks in the wall surfaces as well as priming them for optimal results.
You probably don't need a primer. If the current wall is smooth, clean and covered with the same type of paint (both are oil-based for example), you can head straight for the paint. You need to fill holes, spackle and sand*, maybe even cut a new piece of drywall in to the existing wall.
As noted above, most paint manufacturers recommend that you clean walls with at least mild detergent and water before painting. Although modern paints are so good that they bond well to almost any surface, it will adhere best to surfaces that are perfectly clean and smooth.
Clean walls after sanding
If you've just sanded your wall, perhaps after applying a dollop of filler to a crack, then you'll need to clean it before going any further. This will prevent that stray plaster dust from nestling into the carpet or getting mixed up with your paint.
To achieve a nice smooth finish, it's essential to sand to help prepare the area for painting application, by sanding you are removing imperfections (also known as pimples), creating a nice smooth finish while at the same time adding adhesion by developing small, rough ridges for the paint to stick to.
Some paints adhere extremely well to certain surfaces while others need a rough or scuffed-up area for the best application. For example, when working with bathroom trim or kitchen cabinets with semi-gloss or high-gloss finishes, you'll most definitely need to sand between coats.
Two coats of paint ALWAYS looks better and more professional than just one. The best paints sold by top paint vendors recommend a two coat system.
If you don't sand between layers of polyurethane, the surface may become streaky or discolored. This formula prevents chemical solvents from bonding to it. Once the first layer of paint is dry, you can apply a second coat to make sure everything remains. Each coat of oil-based polyurethane finishes is applied on top.
Prep the Walls
When preparing your walls, professional painters will usually begin by removing any debris that protrudes from the walls such as glue, wallpaper or paint. They are looking to create as smooth of a painting surface as possible and will take time to remove any texture.
After sanding a piece of wood, you'll need to clean it before adding a stain or paint. You can use a variety of tools and techniques to remove sanding dust from your wooden surface. Just make sure you get the surface of your project as clean as possible before adding any paint or stains to finish the piece.
Stick with Warm Water or Mild Soap
Glossy paint: All-purpose cleaner or dish soap and water. White paint: Baking soda and water. Latex paint: Dish soap and water, or vegetable oil-based cleaner. Oil-based paint: White vinegar, or dish soap and water.