Painting over newly plastered walls requires careful preparation and patience to ensure a smooth, long-lasting finish. Rushing the process or skipping essential steps can lead to peeling, cracking, and other issues that compromise the quality of your work.
Here’s a step-by-step guide to help you get it right.
Let’s get straight to the point.
To paint on fresh plaster, ensure it’s completely dry (1-4 weeks), then apply a mist coat—a diluted layer of emulsion paint—to help the paint adhere properly. Avoid using PVA as a sealer.
Use breathable paint to let moisture escape. Apply thin layers, allowing each coat to dry fully. Sand only if there are imperfections. Be patient and follow these steps to avoid issues like peeling or cracking and achieve a smooth, lasting finish.
Understanding The Basics Of Fresh Plaster
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Before starting the painting process, it’s essential to understand why fresh plaster requires special treatment. Plaster is highly absorbent and must be completely dry before applying paint.
Painting directly onto wet plaster can cause the paint to bubble, crack, or peel as the moisture escapes.
How Long Does Plaster Take To Dry?
The drying time of plaster can vary depending on weather conditions, plaster type, application thickness, and the underlying surface. Fresh plaster typically takes one to four weeks to dry completely.
Ensure the plaster surface appears evenly coloured and free of dark patches before proceeding with any paintwork.
Guide In Painting On Fresh Plaster
Step 1: Preparing The Surface
Proper preparation of the plastered surface is important for a flawless finish. Follow these steps to prepare the wall for painting.
1. Clean And Inspect The Wall
- Clean the surface: Remove dust or loose particles using a dry cloth or brush.
- Inspect for cracks or gaps: Fill any or small gaps with elastomeric acrylic caulk to prevent movement.
2 . Allow The Plaster To Dry Completely
- Wait for at least one week: Ideally, the plaster should dry for three to four weeks, depending on the conditions.
- Check for even colouring: The plaster should appear uniformly light and consistent.
Step 2: Applying A Mist Coat
A mist coat is essential when painting new plaster. It acts as a primer, allowing the paint to adhere properly.
1. What Is A Mist Coat?
A mist coat is a watered-down layer of emulsion paint penetrating the plaster’s surface, sealing it for subsequent coats. It helps prevent the topcoat from flaking by ensuring a strong bond with the plaster.
2. How To Make A Mist Coat
- Mix the paint and water: Combine three parts of water-based matt emulsion with one part of water until it reaches the consistency of a single cream.
- Apply the mist coat: Use a paintbrush or roller to apply the mist coat evenly on the wall.
3 . Allow The Mist Coat To Dry
- Drying time: Let the mist coat dry for at least 24 hours before applying further coats.
Step 3: Painting The Plastered Wall
Once the mist coat has dried, you can move on to the main painting stages.
1. Tools You’ll Need
- High-quality rollers
- Paintbrushes for edges and corners
- Stepladders for reaching high areas
- Masking tape for clean lines
- Disposable plastic sleeves to protect surfaces
2. Applying The Base Coat
- Choose a breathable emulsion: Select a paint that allows moisture to escape from the wall.
- Work in layers: Start with a thin coat of your chosen paint and allow it to dry before applying a second layer.
3. Finishing Coats
- Apply multiple layers if needed. To achieve a smooth, even finish, Most fresh plaster walls require at least two coats of top-quality emulsion.
- Wait for each coat to dry: Ensure the previous coat is fully dry before applying the next.
Common Issues On Painting Fresh Plaster And How To Fix Them
Issues can sometimes arise during the painting process. Knowing how to address these problems will save you time and effort.
1. Dealing With Peeling Or Cracking Paint
If the paint starts to peel or crack, it may be due to moisture trapped in the plaster. Here’s how to fix it:
- Scrape off the affected area: Use a paint scraper to remove peeling or cracked paint.
- Sand the surface: Lightly sand the area to ensure a smooth base for the next coat.
- Reapply a mist coat: Apply another to the affected area before painting again.
2. Identifying Damp Areas
If plaster doesn’t dry properly, it could be due to dampness. To resolve this:
- Remove the affected plaster: Strip the plaster back to the brickwork if damp spots persist.
- Apply a render mix: Use a waterproof render to prevent further moisture issues before re-plastering.
Additional Tips For Painting Fresh Plaster
1. Avoid PVA as A Sealer
While PVA glue is sometimes used to seal plaster, it can create a barrier that prevents the paint from adhering properly. For a better bond, use a mist coat.
2. Choose The Right Paint For The Job
- Interior paint: For indoor walls, use a high-quality matt emulsion, which provides a smooth and durable finish.
- Exterior paint: For outdoor walls, select weather-resistant paint to protect the surface from the elements.
3. Sanding Fresh Plaster
Sand new plaster only if it has visible imperfections. Excessive sanding can create a glossy surface, which makes it difficult for paint to adhere.
How To Prevent Issues With Fresh Plaster Painting?
1. Use A Quality Mist Coat
A proper mist coat can help avoid many problems like peeling and cracking. Always dilute the paint to the right consistency for the best results.
2. Avoid Painting In Humid Conditions
Moisture in the air can slow down the drying process of both plaster and paint. Ensure the room is well-ventilated, and avoid painting on damp days.
Common Mistakes To Avoid
1. Skipping The Drying Time
Do not rush the plaster or mist coat’s drying process. This step is important for ensuring a smooth, lasting finish.
2. Using Thick Mist Coats
A mist coat that is too thick can sit on the surface of the plaster rather than penetrate it. To avoid this issue, dilute the mist coat adequately.
Conclusion
Painting freshly plastered walls demands patience and the right technique.
Ensure the plaster is completely dry, apply a properly diluted mist coat, and apply top-quality emulsion to guarantee a flawless, professional-looking finish.
Following these steps will help you avoid common pitfalls and enjoy beautifully painted walls that last.
With the right approach and tools, your freshly plastered surfaces will be well-prepared for any colour you choose.
The key is patience, proper preparation, and using quality materials throughout the process.
Frequently Asked Questions About Plaster
What Is the Best Primer for New Plaster?
You don’t need any special or expensive products to paint new plaster. The best primer is a mist coat that you can easily mix yourself.
What Is a Mist Coat, and Does a New Plaster Need a Mist Coat?
A mist coat is a thinned-down emulsion used to prime newly plastered walls. To make a mist coat, you mix some emulsion paint with water. We mix about one part of water with one part of paint until we end up with a liquid that resembles milk or cream.
Do You Have to Treat New Plaster Before Painting?
Ideally, the plaster needs to be fully dry before painting. Fresh plaster will take around 4-6 weeks to dry fully. Fresh plaster is porous and will, therefore, absorb moisture. If you attempt to paint over plaster that is still damp, the paint is likely to peel off.
How Many Mist Coats Should I Apply to the New Plaster?
In short, applying two mist coats of sealer is rarely necessary, but it will not harm the surface either. However, applying a second mist coat is a good idea to go down the “belt and braces” route.
Should I Leave Windows Open After Plastering?
Leave the window open to allow the room to dry out a little more overnight.
How Soon Can I Paint Over New Plaster?
You might have painted over freshly plastered walls before they were completely dry. If this is the case, it may have already started to peel. Due to continued evaporation, water from the plaster has become “stuck” between the plaster and the paint.
