“Excellent product! I recommend it without hesitation, and I thank the seller for calling me to make the white of this sealer the same white as the furniture product.”
Primers, also called undercoats, are often the most overlooked part of a painting project. Yet choosing the right primer can make all the difference in paint adhesion, coverage, and the durability of the result.
But how do you find your way among all the products available? Which primer should you use on new drywall, a stained surface, or old oil-based paint? In this article, we explain what the different types of primers are for and how to choose the right one for your project.
01
What is the purpose of primers?
Before choosing a primer, it is important to understand its role. Its primary function is to prepare the surface to provide the best possible conditions for the paint to adhere properly. Thanks to primer, it is possible to paint surfaces where a finish coat would have difficulty adhering or simply would not last.
A good primer also helps prevent several common problems, such as peeling, blistering, premature wear, or an uneven finish.
In some cases, it is even essential to achieve the colour you want. For example, if you want to cover a red wall with white paint, a primer keeps you from applying endless finish coats to make the original colour disappear.
Finally, even though it is an extra step, primer saves time and money. By improving paint coverage and reducing the risk of failure, it reduces the number of coats needed and allows you to get a durable result from the first application.
Since each surface comes with its own challenges, there are several types of primers, each designed to address a very specific situation.
| If your surface is... | Recommended primer |
|---|---|
| Stained by contaminants (smoke, nicotine, water damage, etc.) | Sealing primer |
| Very porous, like a new drywall wall | New drywall primer |
| Very smooth, like ceramic, PVC, or laminate | High-bond primer |
| You are switching from oil-based paint to water-based paint | Oil-based primer or high-bond primer |
02
What is the difference between a primer and a 2-in-1 paint?
Before going any further, letâs clear up a misunderstanding that has spread since â2-in-1â paints appeared on the market.
â2-in-1â paints are marketed as having a primer built into their formula. While it is true that 2-in-1 paints have improved coverage, they do not seal surfaces and do not cover colours the way a primer does.
So it is very important not to replace primer with a 2-in-1 paint if your surface has irregularities (refer to the table above).
03
Primers for previously painted surfaces
This type of primer is the most common, which is why it is also called an âall-purpose primer.â You can use it for the vast majority of your painting projects. Its main use is usually when you want to cover a dark colour with a lighter one. Conversely, you can also use it to get better coverage with a dark paint.
You can also use it to improve the adhesion of your finish paint on your walls. That way, you ensure you increase its durability against wear.
Another reason to apply a primer? To make sure you cover everything in only 2 finish coats. Since primer costs less than finish paint, it can be a good way to save money.
Here are two popular all-purpose primers at Colobar:
1) Passeport Ălite All-Purpose Primer-Sealer
Price per sq ft: $0.12
- Coverage: 450 sq ft per gallon
- Sizes: 3.78 L (Gallon) and 18.9 L (5 Gallons)
- Dry to the touch: 1 hr
- Dry before topcoat: 2â3 hrs
- VOC: 100 g/L
“Very good product, easy to apply and great coverage.
Lemieux M. , client confirmé
Thank you to the Colorbar team for suggesting this product.”
Cover a dark colour more easily
It can be quite frustrating to try to paint over a dark or bright colour, like red or yellow. Sometimes you need up to 4 or 5 finish coats to cover the old colour properly!
If you want to reduce the number of finish coats, apply a coat of tinted primer in the shade of the colour you want. That way, you will be able to cover with only 2 or 3 finish coats.
04
Painting over old oil-based paint
If your wall has already been painted with oil-based paint, you cannot apply a water-based paint directly over it. The paint will not adhere properly and may peel or come off in large sheets after only a few days.
To make this transition successfully, you must first apply a suitable primer.
Option 1) Apply an oil-based primer
Price per sq ft: $0.23
- Fast drying â 2 hours before the next coat
- Adheres to any surface and sands easily
- Designed for interior and exterior surfaces
- High-hiding formula that blocks most stains
- Excellent for sealing water-soluble tannin bleed on cedar and redwood
- Seals pencil marks, graffiti, rust, and nicotine and smoke stains
This is the most durable solution. Oil-based primers adhere perfectly to old oil-based paints and can then be topcoated with a water-based paint.
The main drawback? They give off a strong odour, require a solvent for cleanup, and are generally less pleasant to use.
Option 2) Apply a water-based high-bond primer
“A primer that works very well on kitchen cabinets. Same thing for transitioning from oil-based paint to latex paint on walls. ”
Chantal , cliente confirmée
If you prefer to avoid solvent-based products, a high-bond primer like the STIX is an excellent alternative.
Designed to adhere to very smooth surfaces, it generally allows you to cover old oil-based paint before applying a water-based paint. Its adhesion remains slightly lower than that of an oil-based primer, but it is much more pleasant to use day to day.
If you are looking for maximum performance, oil-based primer remains the benchmark. If you prioritize ease of application and a less odorous product, a high-bond primer is an excellent compromise.
05
Choosing a primer for porous surfaces
New drywall is a very porous surface. If you apply a finish paint directly, part of the product will be absorbed by the wall, which can lead to an uneven finish, roller marks, or a difference in sheen.
To avoid this problem, first apply a primer specifically designed for porous surfaces. Its formula helps seal the pores of the drywall and create a uniform surface before painting.
In addition to improving the final result, a new drywall primer often helps reduce the amount of paint needed. You save time and paint, and you increase your chances of getting a beautiful finish from the first coats. <
1) Benjamin Moore K265-00 Interior Primer-Sealer for New Drywall
“always an excellent primer; on new drywall it blocks the pores so you need fewer coats of colour paint afterward”
Michel Cobetto, client confirmé
Price per sq ft: $0.10
- Sizes: 3.78 L Gallon and 18.9 L 5 Gallons
- Dry to the touch: 1 hr
- Dry before topcoat: 2â4 hrs
- VOC: 200 g/L
Estimated delivery: 2-3 business days
In-store pickup available
06
Specialty primers
High-bond primers for smooth surfaces
Some surfaces are so smooth that a finish paint simply cannot adhere properly. That is exactly the kind of situation high-bond primers are made for.
Their role is to create a bonding layer between the surface and the finish paint. Once applied, the primer provides a surface that the paint can adhere to much more durably.
This type of primer is generally used on materials such as ceramic, PVC, plastic, glass, glazed blocks, old glossy paint, fiberglass, as well as many metals such as aluminum, copper, or galvanized steel.
It is also one of the most versatile primers on the market. It is compatible with most finishing systems, whether acrylic, alkyd, urethane, epoxy, or even certain lacquer finishes.
When you are dealing with a particularly smooth surface and wondering whether the paint will hold, a high-bond primer is often the solution.
“I am very satisfied.
Martine Turcotte, cliente confirmée
The product goes on well and covers very well”
“Hello,
Anne, cliente confirmée
I was very satisfied with this product and Colobarâs service.
Attentive listening and incredible service.
Thank you very much, and see you next time, of course.”
Sealing primers for stains and bad odours
Some stains are much more stubborn than they look. Even after several coats of paint, they can reappear and ruin the result. That is exactly the role of a sealing primer: to prevent contaminants from bleeding through the new paint.
This type of primer is used on surfaces stained by smoke, soot, nicotine, water damage, certain mould, or other contaminants that are difficult to hide.
Sealing primers are also very effective at trapping bad odours. If a room still smells of cigarettes, smoke, or stale air, they help block those odours before applying the finish paint.
In short, if your problem is not coming from the paint but from the wall itself, a sealing primer is generally the best solution.
Price per sq ft: $0.16
- Available colours: White
- Sheen (or gloss): Primer
- Cleanup: Solvent
- Resin type: Alkyd
- Recommended uses: Interior, Exterior
- MPI rating: 69
- VOC content: 337.2
Estimated delivery: 2-3 business days
In-store pickup available
Shellac-based primers for sealing knots
Shellac-based primers are high-performance sealing primers, but they have an additional advantage: they are particularly effective at blocking wood knots.
Over time, some knots can allow tannins or resin to bleed through the paint, creating yellowish stains that are difficult to remove. A shellac-based primer durably blocks this bleed-through and prevents it from reappearing.
Since these products are more expensive, it is generally not necessary to apply them over the entire surface. In most cases, it is enough to treat only the knots before applying a conventional primer or directly the paint, depending on the project.
The main drawback? Their strong odour. Work in a well-ventilated area and wear the appropriate protective equipment during application. Despite this, when it comes to blocking wood knots, shellac remains the go-to solution.
Price per sq ft: $0.24
- Sizes: 946 ml and 3.78 L Gallon
- Dry to the touch: 20 min
- Dry before topcoat: 45 min
- VOC: 550 g/L
Estimated delivery: 2-3 business days
In-store pickup available
- Zinsser B-I-N shellac-based sealing primer
Price per sq ft: $0.33
- Covers about 400â500 sq ft/gallon
- For interior use and exterior touch-ups
- Best stain-blocking sealer
- Seals knots and sap streaks
- Seals pet, smoke, and mould odours
- Recoat after 45 minutes
Estimated delivery: 2-3 business days
In-store pickup available
Start your project now!
You will find all the products you need on our website.
- Start by measuring the dimensions of the surface you need to paint.
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- A gallon of primer covers between 300 and 500 sq ft depending on the product.
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- Choose the primer that best suits your painting project.
- Place your order online and choose between in-store pickup and home delivery.
Want more tips for your painting project? Check out our blog dedicated to the topic.
Products found in this article.
Primer-Sealer and Multi-Purpose Primer by Passeport Elite
Zinsser Cover Stain oil-based primer
Waterborne Bonding Primer STIX
FAQ
Q. How do I know if my wall has already been painted with oil-based paint?
If you do not know the roomâs history, do a test with a cloth soaked in mineral spirits. If the paint softens or leaves colour on the cloth, it is probably a water-based paint. If nothing happens, it may be oil-based paint. When in doubt, it is better to apply a compatible primer than to risk an adhesion problem.
Q. Can a primer fix poor surface preparation?
No. A primer improves adhesion, but it never replaces proper preparation. If the surface is dusty, greasy, crumbling, or the old paint is already peeling, the problem will come back sooner or later, even with the best primer on the market.
Q. Can I use the same primer for the whole house?
Not always. A primer that works perfectly on new drywall will not necessarily be suitable for ceramic, a melamine piece of furniture, or a wall stained by nicotine. Choosing the primer based on the substrate is often what makes the difference between paint that lasts for years… and paint that peels after a few months.
Q. What should I do if I discover stains after applying the first coat of paint?
Do not continue applying finish coats hoping they will disappear. Nicotine, smoke, tannin, or water stains tend to reappear through the paint. It is better to let it dry, apply a suitable sealing primer to the affected areas, then resume the finish.
Q. Is there a maximum time before I can apply paint over a primer?
Yes. Even though many primers can remain exposed for some time, it is best to apply the finish paint within the timeframe recommended by the manufacturer. If you wait several weeks or several months, dust and contaminants can build up on the surface, which can reduce paint adhesion.
Q. Can you apply primer only in certain areas?
Absolutely. It is even sometimes the recommended approach. For example, if only a few wood knots, repairs, or stains require special treatment, you can apply a specialty primer only in those areas, then use a more versatile primerâor paint directly, depending on the manufacturerâs recommendationsâon the rest of the surface. You get the same result while reducing costs.
