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Painting a room (or an entire home) can both be an incredibly relaxing, and a bit of a bothersome activity. In order to achieve the most even and long-lasting results, you should use a primer before you apply your coat of paint, especially if the wall you are painting is uneven, or if you are going from a dark to a light colour.
The question you are likely asking yourself though, having just purchased your cans of primer and paint, is how long you have to wait for the primer to dry.
Let’s answer that one for you.
How Long to Wait Between Primer and Paint?
Shellac primers can be completely dry in as little as 45 minutes. If you are using a latex, also called a water-based primer, you will need to wait 3 hours before you apply a coat of paint. If you have chosen an oil-based primer, you will need to give it 6 to 8 hours to dry.
Check to make sure the primer is in fact dry, and give it some extra time, just to be on the safe side.
What is a Paint Primer?
A paint primer is a base coat, an undercoat if you will, that prepares surfaces for painting.
Primers provide a uniform surface to paint over, ensuring the paint sticks better and lasts for a longer period of time. It makes for smooth application, and allows you to use fewer coats of paint.
By using a primer, you can cover up any imperfections on your walls and conceal any existing stains, so that they don’t bleed through your fresh coat of paint.
Primer can also neutralise the colour of the surface you are painting over, providing the most brilliant colour payoff, and the truest hues.
How Long Does Primer Take to Dry?
How long the primer takes to dry will depend on the type of primer you are using, the surface being primed, and the weather conditions.
- Oil-based primers are the slowest-drying primer, and will take 6 to 8 hours to dry. It may take even longer if the air is particularly humid.
- Latex primers, or water-based primers, are rather fast-drying, and will require around 3 to 4 hours. Leaving them a bit longer will ensure the entire surface has dried evenly.
- Shellac primers dry super fast, and can be ready to paint over in as little as 45 minutes. Giving them an extra 15 can round off your waiting time nicely, and make for a smooth paint application.
The temperature and humidity of the room you are painting will also impact primer drying time. The more humid the air, the longer the primer will take to dry.
The ideal painting and priming conditions are around 21 degrees Celsius and 50% humidity. If it is more humid than that, you may want to prolong your primer drying time.
Also bear in mind that temperature is less important than humidity: paint and primer will dry faster on a cold, dry day, than on a hot and humid one, so you are more than welcome to paint your walls in the middle of winter.
How to Know When the Primer is Dry?
The best way to determine if a primer is dry is to lightly touch it with a finger. If the primer is no longer sticky or tacky, and if none of it comes off on your finger, it is dry.
Make sure to check multiple areas, to ensure the entire surface is evenly dry. Check the corners and the middle of your wall, especially if there is a patch that may be exposed to more humidity than others.
If you believe your primer has completely dried, give it another 30 minutes, just to be on the absolute safe side.
What Happens If You Wait Too Long to Paint Over Primer?
If you wait too long to paint over your primer, it will lose its effectiveness, and you will most likely need to re-prime.
The longer you leave the primer to sit, the less effective its grip will become, and you may end up with blotchy, uneven paint. Chances are a fair amount of dust will also build up on your coat of primer, messing up the smoothness of your walls.
If you have left the primer for too long, it’s always better to add a second coat of primer, to ensure you get a finish you will be happy with. Just make sure you apply that coat of paint on time this time around.
How Many Coats of Primer Do You Need?
In most cases, you will need to use only 1 coat of primer. Rarely, a project might require 2 coats.
You can use a single coat of primer when:
- You are only slightly changing the colour of your wall
- You are painting over an oil or latex paint
- Your wall isn’t heavily stained + the primer you are using has stain blocking power
- You are priming drywall
- You are priming wood
You may need two coats of primer when:
- You are painting over a dark colour
- You are painting over unfinished drywall
- You can still see the old colour underneath
Do I Need to Sand After Priming?
You should only sand after priming to remove any brush marks or uneven texture on the primer itself.
To achieve the best effect, you should sand your surfaces first, and then prime them. Make sure you also get rid of all the dust and debris before applying the primer, as it will come out uneven and blotchy.
Once your primer has dried, you can sand away any rough primer texture – and then apply your coat of paint.
Can I Prime and Paint the Same Day?
Yes, especially if you are using a water-based primer, as you will only need to wait 3 hours for it to dry. Oil-based primers can take around 8 hours to dry, so if you start very early in the morning, you can still fit in a coat of paint in the evening.
Plan your painting jobs ahead, to ensure you have plenty of time to finish them in a reasonable hour. You don’t need to start at the crack of dawn, but consider your primer drying time before you crack the roller out.
Wrapping It Up
Priming and painting can be the ultimate mindfulness activity, if you choose to look at it that way. I’m not advocating that you sit in a room and watch paint dry for a couple of hours – just to let your mind wander while you are rolling your primer and colour out.
Remember: the better you prime your walls, the smoother and truer you paint will be, so give your primer plenty of time to dry, and get yourself a quality roller.