Paint and plaster are the two main ingredients to complete a home makeover. When painting walls in your home, those pesky little imperfections can ruin the whole job. This is particularly true when wet paint on newer plaster is improperly cured or painted over with another coat.
Matching paint colors can be difficult or impossible when you run into a patchy wall, especially if there are textured patterns such as brickwork, wood grain, or even flaking stucco. To avoid paint runs and blisters, it’s important to understand why this problem occurs and what you can do about it.
Painting fresh plaster is a pretty simple DIY project that doesn’t require any specialized primers or paints. However, there are a few things you must take into account before painting your freshly plastered walls. So, what causes patchy paint on new plaster, and what can you do to remedy the look? Here’s everything you need to know.
What causes patchy paint on new plaster?
First, you need to understand how plaster walls are created. Newly plastered walls go through three stages before they are painted. These are the “wet” stage, followed by the “tack” stage, then a final drying period.
Plaster dries quickly during the “wet” stage and becomes incredibly hard. This doesn’t last for long, however. It needs to be cured or dried out to become strong enough to support the finishing coats of paint. For this reason, you can expect a patchy wall where paint runs on a plaster surface.
A second reason for a patchy paint or plaster finish is when paint goes on thick or dries with a textured surface – such as antiseptics or an eggshell finish – it’s prone to cracking when the plaster dries. In warm, humid climates, this is particularly true. When the paint cracks, moisture can get inside and cause mold and smell. The only way to fully remedy the situation is to remove the paint.
Another reason for a patchy paint or plaster finish is that the type of wall you’re dealing with may not be compatible with traditional paint colors. The color tone of your wall may differ from other walls in the same room, so choosing colors that match the wall rather than the floor makes more sense. To avoid paint and plaster running on your walls, look for paints with subtle tone-matching formulas.
Unfortunately, this is why homeowners have painted furniture, such as dressers and nightstands, in their bedrooms. The paint on these items almost always goes patchy once the plaster in the room is exposed. If you discover that you must repaint new plaster, there are a few ways to prevent paint blobs and patchy coverage.
How to Prevent Paint Runs on Plaster
The easiest fix is to work with a drywall applicator, which can help you understand what causes paint runs on plaster. You can also use these tips:
Avoid painting in areas with a lot of steam or moisture problems. Painting in a hot room will make your job much harder. Let the plaster cure for about a week before painting over it. Use roller covers that have a sealant coating and extra nap in them. This will help you load paint onto the roller more easily.
You’ll get a better finish when applying the first coat of paint, although you should expect patchy areas on your wall. Before applying your second coat, wait until all moisture has been wiped away from the wall. If you try to paint while there’s still moisture left in the plaster, it will seep into the paint and ruin it.
The key to painting over a patchy plaster surface is not to try and cover every tiny imperfection. Instead, focus on the larger areas that need a coat of paint. The above tips can help you avoid paint runs on plaster, so you’ll still have a nice, smooth surface that looks great with your new colors.
Will patchy paint on new plaster ever disappear, and what can you do to make it disappear?
You must be careful when painting a room with fresh plaster walls or ceilings. The first coat of paint may go smoothly, but the second coat may result in flaws, uneven coverage, and an overall finish that looks “patchy.” This is because a few things must be done right the first time when painting new plaster, so second-coat painting is rarely successful when all that’s done is a touch-up.
Step-by-Step Guide on How to Paint a Newly Plastered Wall
- Step 1:Let the plaster dry completely.
This may take up to 30 days; thus, it’s best to start early. Check the plaster with your finger. It should be firm and not feel moist or sticky.
- Step 2:Sand the wall to create a smooth surface for paint.
Use sandpaper with a grade between medium and fine. Begin at the wall’s peak and move down in smooth strokes. Go over the entire wall this way. When you’re through, the surface ought to be touchably smooth.
- Step 3:Wash the wall with a masonry wash.
Washing the wall will remove dirt and any residue that would cause paint bubbles or bumps. Use a masonry wash made for painted plaster because traditional house wash soap might cause paint to peel. After washing, let the wall dry completely.
- Step 4:Prime the wall.
Use latex primer, as this is best for painted plaster walls. You can also use an oil-based primer, which may create a stronger paint film. The primer should cover all of the bumps and texture in the plaster, leaving a smooth surface for the paint to adhere to.
- Step 5:Paint the wall’s final color.
Now you can choose the paint color you want! Please wait a few days for the primer to dry before top coating it.
How to Prevent Patchy Paint on New Plaster
Once you’ve followed these steps, your wall should be ready to get painted without issues. However, if the paint starts cracking when the plaster starts drying, you’ll need to remove the paint.
Patching painted plaster isn’t easy, as paint doesn’t stick to already-painted surfaces. To patch painted plaster:
- Remove the paint using sandpaper or a paint stripper.
- Rough up the surface of the plaster with sandpaper until it’s smooth and even.
- Paint the repaired area with latex paint, following the above instructions for painting on new plaster.
Why you should seal your plastered wall
It would be best if you sealed your plastered wall because plaster is porous, which means it absorbs water, oil, and dirt like a sponge. Dirt and oil collected in the pores of plaster over time will affect its appearance. By sealing the surface, you can prevent dirt and oil penetration from preserving your wall for longer.
Also, sealing the surface of your painted plaster is important to protect it against water damage. The plaster can absorb water through the cracks and pores of your wall. In other words, the moisture in the air, when it comes into contact with your wet plaster and paint, will cause it to peel off. When this happens, you will wonder why your painted walls are peeling off. Fortunately, this article will help you find a good solution to such a problem.
There is no single way to seal a plastered surface that is foolproof. The reason is that different types of plaster have different chemical compositions and react differently to sealants. The greatest method to learn is via trial and error. Find out what works for your wall.
Warnings about painting on new plaster
Once your walls are painted and dry, it can be tempting to put things up on them right away. However, before hanging anything, you should wait until your paint is fully cured.
Also, remember that paint colors and textures can make a big difference in a room. So, if you’re considering painting over plaster with masonite or wood paneling, you may not like the results.
It’s better to leave the walls as they are and add wall coverings or furniture if you don’t like the look.
Finally, keep in mind that plaster needs to be well-covered with paint to protect it from moisture and humidity. So, if you don’t paint it, the underlying material will eventually crack and bleed water. And if you sand-painted plaster, you’ll also remove the barrier between the material and moisture.
Follow these easy steps, and your plaster walls can look beautiful for years! You may even decide to keep the front wall of your home painted after seeing the results. And if you do decide to remodel it, the job will be much easier because you’ve already prepared the surface.
Paint runs may be frustrating, especially if you have a lot of work to finish in a short period. Still, with proper technique, you can avoid patchy plaster and paint. Keep following us for more expert advice on painting over plaster.
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