Home Improvement

The ULTIMATE Guide to Painting Newly-Plastered Ceilings and Walls

Fantastic Team
Published: May 13/2019
Last update: Sep 29/2023
11min read
Views: 25,821

Painting newly-plastered walls and ceilings sound like a simple task. “I just grab a handy roller and paint, right?” Nope!

Actually, the new plaster is among the most challenging surfaces to paint successfully. When you don’t choose the right primer or even skip priming, you may get into huge trouble – the displeasure of cracking, peeling or badly-stained paint.

Table of Contents:

Things you must know before painting new plaster
Why is it difficult to paint freshly-plastered ceilings and walls?
When is plaster ready to paint?
How can I tell if the newly-plastered surface is dry enough?
Is it possible to dry plaster quickly?
How to prepare new plaster for painting?
Final steps to achieve a smooth finish

So, if you are a new homeowner, DIY enthusiast or just someone:

starting his first plaster painting project over plaster;
willing to receive tips from the experts out there;
in a hurry to give a whole new flavour to his home,

you have stumbled upon the right article.

Before you dip the roller..

Discover the secrets of painting over plaster and find the answers to the most important questions. Then, get the perfect finish!

4 Things you MUST know before you start painting new plaster

Why is it difficult to paint freshly-plastered ceilings and walls?

Do you know that a standard newly-plastered room may keep 1 ton of water? We guess you are surprised.

The fresh plaster not only contains large amounts of water, but it’s extremely absorbent and soaks up any new moisture interacting with its surface. This is often valid for the material it’s applied to. If you don’t take into account their porous nature and start painting directly onto wet plaster, you’ll run into many difficulties along the way.

Likewise, when you go with the most common paints, they form a vapour barrier on top of the plaster. Don’t opt for this route as these types of thick paint trap the moisture behind the plaster and prevent it from evaporating. In the worst-case scenario, the humidity will go through the tiniest cracks and foundation and wreak havoc in other parts of your home. It could be mould, efflorescence (salting), an uneven and patchy look, hairline cracks, smells like something is moist…. the list goes on…

So, don’t allow all your painting efforts to be in vain. To play safe and wait is the best thing you can do. And unlike general recommendations to start painting in a week or two, always wait a bit longer until the plaster is perfectly dry. Otherwise, you’ll be flushing money down the drain.

When is plaster ready to paint? Or how long you should wait?

In the first place, if you need recommendations on the curing time, consult with the handyman who handles the plasterwork in advance. But generally, the ceiling or the wall will be ready for painting a month after plastering.

Yet, the plaster drying time could last even longer. The reasons could be indoor and outdoor humidity, excessive condensation, temperature changes, the multi-coat plaster system, ventilation, etc. Also, wet spaces like kitchens, laundries and bathrooms can create and keep moisture, so they often need more time to dry thoroughly.

Before embarking on the task, mind that there are certain seasons favourable for painting. Because of the mild temperatures and comparatively low outside humidity, we recommend doing the painting in spring. These are excellent opportunities to “spring” yourself into interior painting.

You can read even more on this topic by checking our post on how long to leave new plaster before painting.

How can I tell if the newly-plastered surface is dry enough?

If you are not sure whether to keep going or wait a bit longer to let the plaster dry, stick to these tips:

Watch out for colour consistency. A typical sign of wet plaster is a dark, blotchy surface. Normally, during the drying time, you may notice that the ceiling/walls will lighten its colour until the moment it gets smooth and uniform. Only then it’s dry enough and acceptable for painting. But if you spot even the smallest dark stain, don’t undertake anything before it disappears.
Use a moisture meter. It’s a great assistant to determine whether the surface has consistent levels of damp throughout. Yet, mind that the percent that appears on the screen is not the actual dampness throughout the whole freshly-laid plaster. So, don’t forget to check the humidity at a few different points.

Is it possible and how to dry plaster quickly?

The best way to dry plaster is always the natural way. Not surprisingly, this is often a slow and tedious process. Though, if you want to speed up the drying process, try the following steps:

Best practices:

Ventilate the room. If it’s not a rainy day, leave the windows and/or doors open to encourage the air movement around the room. During sunny days, it’s the most effective and safest way to take away the damp air.
Keep an eye for any signs of leaky gutters, wet patches, rots on external doors, bad insulation, etc. Caulk even the tiniest cracks to keep out the moisture. Otherwise, you risk the excessive dampness to concentrate on the porous plaster. Sooner or later, this will trap all kinds of problems (without you even suspecting them). That’s why it’s crucial to damp-proof the building before painting and even before plastering;
Remove the carpets, furniture and textiles (if possible) as they keep moisture. All in all, you’ll free up more space and give a chance for better ventilation.

Bad practices:

Using a dehumidifier, Air Conditioner, ceiling fan, etc. You may think “Why not to help my newly-plastered ceiling dry quickly”? For those of you who are in a hurry, it may sound like a good idea. Sorry, if we are disappointing you, but this simple remedy can cause plaster shrinkage and [afterwards] the resultant cracks. Yet, if you turn on the AC, set it on a dehumidifying regime and set the flaps to push down the air. In most cases, its capacity for drying the air is limited compared to a dehumidifier. This makes it a less dangerous option for your freshly-plastered home.
Turning up the central heating thermostat. Most Brits will go this way in winter. But this is wrong. Try not to use radiators to speed up the plaster drying time. When you are raising the thermostat, you only heat up the wet air molecules and speed up the condensation. On the contrary, turning down the thermostat (even switching it off) offers a more natural way to lower the moisture in the space.

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How to prepare the newly-plastered ceiling and walls for painting
[80% of the plaster painting process]

Step #1. Decide on primer to seal the bare plaster before painting

If you want to admire your work, applying a plaster priming sealer is a MUST! Priming saves paint. It also offers an added bonus: prolonged drying time allowing the plaster to withstand the test of time.

Not surprisingly, there are a ton of alternative primers of new plaster. But selecting a primer can often be more complicated than you think. That’s why we created a brief comparison between home-made mist coat mix and trade paint for bare plaster. Have a look and be sure you made an informed decision!

Mist coat vs Trade paint for bare plaster

Pros and cons of the mist coat

Cheaper than the bare plaster trade paint;
Custom preparation according to the specific new plaster properties. So, it’s easier to get a good finish;
Produce smooth coating adhering well with the fresh plaster.

It’s up to your skills and intuition to mix a good adhering substance;
Mist coat emulsion could splash a bit more than most of the specialized bare plaster paints;
Longer waiting time before painting (yet, the result 100% is worth the wait).

Pros and cons of the bare plaster paint
(“Supermatt”, “Contract matt”, “Microporous paint for new plaster”)

Less dripping paint and messy experience;
A time-saving solution – perfect for all busy homeowners who are looking for a straightforward and handy product. Designed for early priming of newly-plastered surfaces;
Detailed instructions for proper paint preparation;
Promise a “breathable” surface that releases the moisture back in the air.

More expensive & coverage depends on the type of surface;
Most of the paints designed for direct application on bare plaster are thinner than the common wall and ceiling paints but produce a “hard” edge. You can find it difficult to achieve an excellent finish with them;
Tend to peel off more in the long term and due to temperature changes;
As the paint substance is comparatively thin, it may be necessary to apply a second coat of emulsion.

Step #2. Ensure you have all painting supplies in advance

It’s tempting to start the painting job as soon as possible. The truth, however, is that you need at least a couple of days to prepare for the job.

Start by setting up some free space, removing or taping all fixtures, hardware and furniture. Also, devote some comfortable and loose clothes to the painting project. Ensure that all necessary equipment and products are at a hand’s reach so the smooth painting process won’t be interrupted by something you forgot to deliver.

Instead of writing everything down, we’ve gathered all necessary tools and safety equipment in a single checklist.

Click and download the painting supplies checklist for your newly-plastered ceilings and walls here.

Step #3. In case of imperfections, sand the plaster first

You can just go on and paint. But the final result will reveal the truth if there are some scratches or lumps marked by accident. That’s why you need to assess the ceiling and/or wall surface first: is it rough or smooth?

Hire professional plastering services to have a surface sleek on the touch and ready for priming. In case you spot an uneven surface or a few bumps stuck to the surface, then you’ll need a piece of sandpaper to help your paint job.

Mind that sanding plaster ceiling and walls will be a messy and time-consuming part of the overall project. But its primary goal is vital for the finish: to assure better adherence between the plaster and the paint. If you have muscles to do the sanding job on your own, rent a stable scaffolding, put on a dust mask and get down to the task. Otherwise, book a reliable handyman to deal with the dirty job instead of you.

If you believe you can handle this task on your own, there are some tips to consider before starting the plaster sanding:

Use a handy piece of fine-grade sandpaper (e.g. 120 grit/mid-grade) to rub down any irregularities gently;
Control it with a light touch to avoid ending up with over-sanding;
Don’t clean the dust to avoid the risk of messing up the perfect finish;
Prime the new plaster to tackle the dust specks.

Step #4. Seal the freshly-plastered ceiling and walls with a mist coat

If you’re not afraid of dripping paint, try priming (sealing) the surface with a diluted first coat of paint. It is known as “mist coat” – a decent non-vinyl, watered-down emulsion preventing the paint from drying too fast and turning the plaster into a dust-free, breathable, and non-porous surface. It offers an extra measure of assurance that the surface will better bond to the paint. And together with proper painting technique application, you’ll receive a uniform, professional look from the first time.

Eventually, it’s all you are looking for!

The GOOD choice of primer for new plaster

While the brand is up to your preference, basic paint ingredients are crucial for reducing the surface suction. The most important thing is to check the label for vinyl substances. Make sure the paint is non-vinyl, only acrylic.

When shopping, opt for relatively inexpensive emulsion paint as you are going to add water anyway. Also, a smooth plaster will benefit from a white, off-white matt or close in colour to the top coat. It will provide a better base for a clear finish.

The BAD choice of paint
Using vinyl and silk paints on new plaster. They are less porous and don’t soak up as fast as the matt. Remember that the new plaster needs to breathe under the paint. These types of paints do exactly the opposite – trap the moisture behind the paint, so often their application ends up peeling or cracking.

Using Polyvinyl Acetate (PVA) primer. Good painting practices deny the application of PVA over plaster. Unlike the matt emulsion paint for new plaster, the PVA application may result in bond loss and plenty of hairline cracks in the short term.

How to seal plaster before painting (4 essential tips & tricks)

Water down the paint for the new plaster.
Pour one part of the paint in a bucket/kettle and mix it with clean, cold water.

In the case of standard mid-thick paint, the following formula should work well: Mist coat mix = 20% water : 80% paint. Next, thoroughly stir with a wooden stick or use a drill attachment to achieve a homogenous mixture. Once you have all prepared and the plaster is dry, dip a brush in the emulsion and test it on a small area. If the plastered surface soaks up the liquid too quickly, don’t hesitate to add more water and apply again.

The paint is still thick? Then, the mist coat formula can be even more elastic so you can mould and shape it according to the specific fresh plaster and paint properties. In such a case, 1 : 1 water to paint mixing ratio would form a more diluted substance going better through the porous plaster. It will seal it providing a good surface ready for priming.
Get the roller ready to apply the base coat.
The rolling technique is the fastest and most efficient way to paint large areas like ceilings and walls.
You’ll cover a greater area more rapidly and it’s better than using a paint brush. But when you have to deal with hard-to-reach spots, edges, skirting boards or door frames, prepare a small brush and dip it in the watered-down emulsion to gently cover all of them. To avoid putting pesky paint dots everywhere, choose the right (and not the cheapest) roller nap that doesn’t splash paint. For superb results, use a medium 3/8″ nap roller cover. Also, for large ceilings and extra-tall walls, the wider the roller, the better. This will ensure a more straightforward application.
Start with the first coat of paint when the plaster is 100% dry.
Once you have prepared the new plaster emulsion, place the paint roller into the tray and ensure it’s wet enough, half- and evenly-loaded. Start priming by doing zig-zag roller strokes forming M or W patterns. This is a proven painting technique allowing for an even finish and minimising the number of paint splashes. Take your time and spread the paint into smaller sections and apply a few strokes while overlapping each previous one. That’s how you continuously maintain a wet edge and a smooth surface without roller marks.

Tip: Lay thin coats of paint perpendicularly to the incoming natural light. You’ll have a better chance to notice any imperfections (such as built-up paint or skipped areas). Slow your roll and don’t press it too hard. Be warned that when your roller speed increases, blemishes are likely to appear as the fresh plaster soaks up liquids quickly.
Follow up with a second coat of the base coat emulsion.
As a whole, it’s possible that one layer is enough to seal the plaster. But it won’t be a stretched truth if we tell you that the first coat is soaked up in seconds after application. So, if the paint is sinking into the freshly-plastered wall or ceiling in no time, a second coat of the diluted emulsion would be a splendid idea. Go on only if 24 h have passed after the first coat of paint on the newly-plastered surface.

Also, a second “mist coat” layer will be necessary when you find any little dips in the surface. We remind you that the paint is not the right tool to use when you want to fill in even the tiniest holes. So, always use a suitable filler. Then, don’t forget to repeat the sanding and mist-coating process locally.

Final essential steps to achieve a smooth finish
[20% of the plaster painting process]

Once the primer is applied, you have 80% of the job done. Allow the mist coat layers to dry overnight, and you will be ready to apply the beautiful top coat. For fast results, allow maximum ventilation. Leave at least one door or window open and ensure the weather forecast doesn’t announce a rainy day onwards.

To ensure perfect coverage, you may want to give the surface a layer of undercoat prior to painting. It will provide a smooth and even base to work with when applying the top coat.

Now, stick to these tips & tricks about the walls and ceiling paint finish and success will follow:

Estimate how much paint you need. Knowing the exact amount of paint for your newly-plastered ceiling or walls can be confusing. It depends on how many coats you’d like to apply, what is the type of paint and the colour you want they to appear. For precise calculations, use a tape measure to determine the length and width of the ceiling. Here is a handy ceiling paint calculator giving you a rough idea about the needed paint. To use a minimum amount of paint for your walls, you can try the following wall painting calculator. Always have in mind a 10-15% waste allowance to assure your tray won’t remain empty when you are already seeing the end of the project.
Decide on the style you want to achieve. Opt for a flat white ceiling paint colour (free from sheen or gloss) when you aim for the walls to visually feel higher, and the room – larger. For example, low-VOC matte paints produce an eco and smooth finish. They are ideal for ceilings since they are camouflaging any imperfection while providing an odourless painting experience. On the contrary, vibrant hues add character and bring sophistication to your room.
Go with the finishing strokes. Now you are on the long-awaited final step. Be sure you provide enough light to start the cut-in around the tight places. That’s how you’ll achieve a neat and elegant finish. Next, glide the roller gently over the paint and lay the finishing coat. The rest of the painting techniques are just the same as the fresh plaster priming job. Once the surface is dry, check if there are any missed areas, small imperfections and if a second coat is needed. In most of the cases, more than one finishing coat will give your room a really professional-looking coverage.

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Takeaways

Whatever application method, primer and tools you choose for painting a newly-plastered ceiling/wall, it takes patience to achieve a long-lasting professional result.
Remember: no mist coat means problems down the line. The fresh plaster will soak up the water content from the paint and cause it to chip off in a few months. If you want to get the most out of your hard painting work, go the extra mile and prepare the surface.
Even if painting over a plaster is not rocket science, it turns out to be neither an easy nor a fast task to deal with. If you need to save some energy, booking professional painting services is the right decision.

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Now we’re sure your interior looks fantastic! Feel free to share your experience with painting new plaster!

Image source: photography33/depositphotos.com