Do You Need To Prime Walls Before Wallpapering?


Do I need to prime the walls before painting?

This is one of the frequently asked questions by customers as a Toronto Condo Painters

The answer for this questions really depends.

let’s look at what primer does first.

The main purpose of primer is to promote adhesion to paint on the painting surface so that the paint can bond to the surface well.

Second, the primer provides better coverage for paint.

Third, it is the base coat for certain colors.


How much do painters charge per room?

How Much Do Painters Charge Per Room? Based on quotes submitted to, the average price paid for house painting per room ranges between $250 – $400 including the cost of paint and materials. In general, the per room cost decreases the more rooms requiring painting in a single job.

How To Pick The Correct Primer For Your Bathroom Walls

Standing in the primer aisle in a Home Depot store could leave you feeling overwhelmed and confused. There is a myriad of primers to choose from! To determine the primer that is right for your bathroom, consider the main problems you want to address or issues you may face in the future.

Stains On Bathroom Walls

You may have watermarks on your bathroom walls that have been caused by steam. These stains are unsightly and, if not treated correctly, will just reappear through your new coat of paint.

Use an oil-based primer to cover up watermarks.

Oil-based primers are also great to use in the bathroom because they are more durable and can withstand moisture.

Pro Tip – Oil-based primer has a powerful smell, so ensure that there is enough ventilation when you are applying the primer to your walls.

Also, check that you can apply latex paint over the oil-based primer. If not, ensure that you can get oil-based paint.

Excessively Damp Bathrooms

Smaller bathrooms or bathrooms with poor ventilation tend to retain a lot of moisture. This causes paint to peel or flake and leads to the formation of mildew.

Applying a moisture-resistant primer will seal the walls and prevent peeling.

Pro Tip – Get rid of mildew before you apply primer. To do this, mix one-part bleach with three parts water and apply to areas infected with mildew. It is a good idea to select a paint that is resistant to mildew as well.

Moldy Bathroom Walls

Mold is an eyesore, but it is also a health hazard. Mold thrives in damp, dark bathrooms with very little or no ventilation.

After cleaning the walls and treating the mold, it is essential to apply a mold-killing primer. A mold-killing primer will cover up the stains left from mold, seal the wall and protect the surface against mold forming in the future.

Pro tip – If you have moldy walls, it is not enough to use a mold-killing primer. Existing mold must be treated and killed. It is essential to keep the bathroom ventilated as well. If there are no windows in the bathroom, installing a steam extraction fan will be a good investment.

Dramatic Paint Color Change

Are you going from deep red to a light and airy, cool blue? Or do you have pale pink walls and would like to go for a bold green? Whether you are going much lighter or much darker, it will take many coats of paint to cover up the present paint color.

Paint experts recommend that you tint your primer grey or a similar color to what you would like your walls to look like. If you use this trick, you won’t have to apply that many coats of paint to your walls to get the color you want.

Pro Tip – Tinting your primer grey, whether you are doing a dramatic color change or not, is always a good idea. A grey-tinted primer will enhance the color of the paint, especially darker paints. Grey-tinted primers will also cover stains and imperfections on your bathroom walls more effectively.

To cover odors

If you’ve just moved into a home and the previous owners smoked, had pets, cooked strong-smelling foods, you’re going to want to prime before you paint. High-quality primers can seal in those odors in a way that regular paint hasn’t been designed to — which means if you don’t prime, those odors will come right back.

When to use primer?

1. Color contrast from dark to light

Picture yourself trying to brush a pale lavender paint over a dark green shade and you will realize very quickly that priming over the dark color is necessary when making a dark to light transition. In some instances, when covering a dark coat of paint, you may need a tinted primer to help the new color look truer to the color swatch you have chosen.

2. Walls that have stains or odor

Scuffed or stained walls can greatly benefit from a coat or two of priming before painting. Some stains, such as crayon scribbles or grease spots, will show through new paint. Surface blemishes may also easily show through a lighter shade of paint so it is worth your time to use a primer if your walls have a few things to hide.

Do not, however, use a primer to cover up mold or mildew on your walls. It will only grow. First, deal with the cause of the mold and remove it. Then you are free to go ahead to prime and paint.

Cigarette smoke and other strong odors can still be left lingering after repainting. Special primers can be used to truly cover the unwanted smells and block them permanently.

3. The surface is porous

It is always a smart idea to prime before you paint a porous surface such as unstained or untreated wood. The surface is porous when it absorbs water, moisture, oil, odors, or stains. Newly installed drywall is highly porous as well but in two ways: the bare facing paper on drywall and the dried joint compound covering the seams. These porous materials will literally absorb your paint right into the wood or drywall if you don’t prime first.

Also, if you have patched or repaired drywall, you will likely have patches of spackle or joint compound on the surface. If these patches are small, there is no need to buy separate primer. You can take a small amount of your regular paint and lightly brush it on the areas you just repaired. When the spots are fully dry, you can paint the wall normally and the spots you worked on won’t show through.

4. When painting over a glossy surface

Glossy surfaces are very hard for paint to stick to. If your wall has been shellacked or been covered in a high gloss or enamel paint, you can try coat after coat of paint and it will never stick

Along with primer, these surfaces may also need some light sanding or buffing beforehand. Doing this will ensure the surface of your walls has enough texture so both the primer and paint can adhere nicely.

5. When you have wallpaper

Whether your wall has some blemishes from the removal of wallpaper or you plan to paint over existing wallpaper, you should definitely plan on using a primer. Each of these surfaces is on the rough side and will benefit from primer.

6. You’re painting over metal or plastic

You can actually find primer that is specifically made for metal. It will help protect from rust and serves as a strong foundation for any future coats of paint.

You definitely need a primer specifically designed for plastic as well. Apply the primer in even amounts to the completely sanded, clean, and dry plastic area.

The Best Sunroom Paint Colors

Painting Over Dark Colors

Anytime you’re going from a dark color to a light color, you’ll want to use a primer to minimize the number of coats of new paint you need to use. Dramatic color changes, like going from dark blue to light yellow or from red to white, will be extremely difficult unless you use a primer. Sometimes you can use a primer tinted with the shade of the new color to help hide the old paint color and provide better coverage.

Do You Size A Painted Wall Before Papering?

The first thing you might be asking is: What is sizing?” Sizing is not measuring a wall, rather, it’s a method to prepare walls for wallpaper that predates modern primers. Most commonly, wall size is diluted wallpaper adhesive applied to the wall before installations. Though paperhangers have experimented with a variety of recipes to improve adhesion:

Wallpaper Manufacturers’ Association of the
Wallpaper Manufacturers’ Association of the United States. Instructor’s Guide – Wallpaper Classes. New York City. 1924.

Sizing’s main purpose is to improve adhesion and to stop the wall from absorbing moisture out of the adhesive prematurely, allowing you to position the wallpaper before it dries. In most cases, when someone recommends sizing a wall, they are recommending priming. However, if you prefer the old school method, ROMAN’s is available.


Painted baseboards lead to a nice, clean look, improving the style and feel of any space. Compared to other paint jobs (e.g., walls and ceilings), baseboards are relatively easy to paint. The issue of priming baseboards is often up for debate because they are located near the floor, not at eye level and as easy to see, and at risk for damage, meaning they will need to be repainted anyway. However, the primary drivers for priming are cost and time.

What happens if I don’t prime my baseboards?

In the long term, probably not much.

If you are going with MDF baseboard, they come pre-primed as the standard option, allowing you to skip straight to painting your finishing coats. If you are painting wood baseboard, you may end up needing to apply extra coats of paint to get the desired look. Priming first allows the less-expensive primer to penetrate the pores of the wood, soaking it up. When the paint is applied, it does not require nearly as much.

Benefits of priming:

Even though you can get away without priming in the majority of situations, it is generally recommended to consider it. Benefits include:

  1. More likely to get the best looking results.
  2. The paint will look closer to your intended look.
  3. The layer of paint will be more durable, with the benefits of a primer to stabilize it on the baseboard.
  4. Helps even out the color and texture of the paint on the baseboard.

Will I save time, not priming my baseboards?

In our experience, including priming in your paint process takes the same amount of time, sometimes less, as it would to only paint your baseboards.

Will I save money, not priming my baseboards?

Assuming you use all your paint, priming can end up cheaper. Primer is less expensive than paint. Using a primer for the first coat or two means you will use less paint.

Priming is part of the process professionals use. However, at the end of the day, the decision to prime your baseboards before painting is up to you, and the results are subjective based on your preference. 

Covering Stains and Odors

Certain stains, such as crayon scribbles or grease spots, will bleed through new paint if the walls aren’t primed first. Additionally, strong odors like cigarette smoke can still seep through new paint. While oil-based primers have a marked scent when they’re curing, they’re better for blocking smoke stains, rust stains, and water-based stains. Painting contractors have found water-based primers work best to cover ink or grease stains.

How much does 3 gallons of paint cover?

Paint Calculator Tip 3: Three gallon cans of paint cover up to 1200 square feet. This is enough to cover a large room or a couple of average-sized rooms adjoining each other.