Patchy paint can result if paint has been applied unevenly. Patchy paint can be down to a variation in surface absorption. Walls might appear patchy if they have variation in texture. Using paint that is not fully mixed can cause a patchy appearance.
Applying the second coat of paint before letting it adequately dry will result in your paint peeling, clumping, and bubbling. It can also result in a different colour than what you intended.
What are common causes of patchy paint drying? Wall has absorbed the paint more in particular areas. Giving an extra thick layer on specific patches. Painting another layer of the whole room. Not allowing enough dry time between each layer of paint. Not following the manufacturer's recommended recoat time.
Patchiness in a painted wall can happen due to several factors, such as applying too thin a coat of paint, uneven surface texture, or not allowing each coat to dry properly before applying the next. Make sure to use quality paint and apply multiple thin layers for better coverage. For more, check out my Quora Profile.
Don't worry if the wall looks patchy at first – this is normal for claypaint. Wait a few hours and you will notice that the colour evens out as it dries (dark colours take much longer to settle to their final colour). We advise that you wait until the colour has settled before applying subsequent coats.
Sand over the drip with medium (100-grit) sandpaper on a sanding block in a circular motion until you can no longer feel the paint ridge or any surface unevenness. Switch to fine (220-grit) sandpaper and sand over the same area to remove any scratches from the previous step.
Lightly sand the troublesome area with 150-grit sandpaper, then tack the walls. That's painter lingo for “Wipe it with a cloth to get rid of dust.” (Easier than the lingo makes it sound!) Then re-paint the area, maintaining a wet edge—meaning, don't let the paint dry until you finish the wall.
The larger patches show through because of differences in the texture of the surrounding wall, which has had several coats of paint applied over the years. So you have roller texture and smooth drywall patches.
You've painted in the wrong weather
If you attempt to paint in full sun or when it is very hot outside, the paint will dry too quickly and won't adhere properly. On the other hand, when you attempt to paint when it's too cold and wet, the opposite will happen and your paint will dry very slowly or not at all!
Reapply another coat to fill in bare spots. If there are clumps or bubbles on the painted surface, sand it, wipe clean, and reapply a coat of paint. To avoid streaks or lap marks from a roller, maintain a wet edge by applying paint toward the unpainted area and then back into the just painted area.
There are several ways to determine whether a surface is dry: OIL BASED products are dry if they are no longer tacky and do not emit a smell. WATER BASED products are dry if they no longer feel cool to the touch and a powder will form with light sanding.
Usually, patchiness in dry ceiling paint is caused by not having a 'wet edge' as you paint. This means keeping the edge of the painted area wet so that when you roll into the next section, it blends smoothly so no lines appear. The only way to even out a patchy ceiling finish is to re-paint the whole ceiling.
Applying the second coat too early will result in lost time, money, and effort. Not only that but it'll also create additional stress that's not necessary. Applying the second coat too early will result in streaks, peeling paint, and uneven color.
If you start applying the second layer before the first one has dried, you'll end up smearing the edges and making streaks. As eager as you might be to finish the job, give your walls time to dry completely before adding another coat.
Not letting paint layers dry:
This can result in a rush to try and do the most in the shortest space of time. Causing us to start painting over a tacky paint layer which makes the new layer mix into the previous one. Leading to an uneven or blotchy application.
Using a high-quality primer provides many benefits, including hiding imperfections and promoting adhesion.
Paint ghosting happens when dust, soot, or other airborne particles cling to walls and ceilings, forming subtle, shadowy patterns. These patterns often show up on cooler surfaces where moisture tends to settle, creating ideal conditions for particles to stick.
Painting over existing layers of paint is usually the easiest option. A paint that has high coverage and a thick texture, such as our Claypaint or Lifestyle emulsions, will even out any hairline cracks and slightly bumpy surfaces. Both products can go over a multitude of wall substrates.
Drips and runs are a clear sign of a bad painting job. These imperfections are typically caused by applying too much paint in one area, or by not being careful during the application process.
The texture and finish of the painted surface can be negatively impacted by overly thick application. For instance, it might obscure details on textured surfaces or woodwork. To avoid these issues, it's important to follow the manufacturer's instructions regarding thinning and application.
If the humidity is too high, the solvents in the paint will take longer to evaporate. This long drying time cause the paint to dry with a darker appearance, though it can also lead to uneven drying, streaks, and paint discoloration.
Not Fully Loading the Roller
The roller needs to be fully loaded with paint to the core, otherwise you'll get air bubbles on your wall, resulting in “paint acne.” To avoid this mistake, roll back and forth on the roller tray until all bubbles are gone and the roller feels heavy.
Using Several Different Coats on the Same Surface
Different types of paint do not bond well. Applying different paint types together on the same surface can result in paint peeling. Oil-based paints do not adhere to latex-based paints and vice versa. To avoid peeling paint, make sure to always use the same paint type.