Here’s Why You Should Prime & Seal Drywall Before Painting?

When you put up new drywall, it may seem that all you need to do is add two coats of regular paint, and you are done.

However, if you want to avoid potential issues with the new paint, you will need to add a coat of primer.

While primer for new drywall may seem at first like an unnecessary step, there are good reasons why and when it should be applied to your new drywall.

The purpose of adding a coat of drywall primer – before you paint – is to provide the paint with a good place where it can stick and hold firmly.

Because the drywall primer is not the same as regular paint, it works by providing better adhesion and finishes to your wall, provided you do it right.

Whether you are priming the drywall in your living room or bedroom, you can choose a thin primer that covers the surface or a thicker version that covers the nicks and marks to create a smooth surface.

Below I will try to cover more about priming the wall and the proper steps to prime your new drywall.

But let’s start with the basics…

What is drywall, what is it made up of, and why is it getting more popular in home construction than ever before?

What is a Drywall?

Drywall panels are primarily made of gypsum.

It’s a naturally occurring, non-toxic mineral found in massive sand beds, or they seem like sand that often has a pink, yellow, or gray tint because of impurities.

Gypsum is mined in 85 countries around the world. The chemical formula of gypsum is CaSO₄·2 H₂O, which shows it comprises a large part of water.

These are in crystalline form, which is why individual gypsum molecules are dry.

To be utilized in the wallboard panel, raw gypsum is heated to partially dry out water molecules from the compound to produce hemihydrates of calcium sulfate, CaSO4· 1⁄2 H2O.

Mixed with various additives such as starch, paper pulp, and an emulsifier (or a thickening agent), a thick gypsum paste is formed by blending the mixture in water.

The final product is a board that’s completed—once again—by sandwiching the wet core between two sheets of fiberglass mats.

This formation passes through drying chambers heated up to 500 degrees Fahrenheit.

The dried material is rigid and robust enough to be cut out in typical sheets of 4×8 feet.

The face paper is the front paper of the panel, which is white, and the back paper is of a light brown shade.

Sizes and Types

Drywall comes in a thickness of ½ inch, ¼ inch, 3/8 inch, and 5/8 inch.

The standard size of a wallboard panel is 4 feet in width and 8 feet in length.

However, popular variations in lengths of 10 to 16 feet are also being introduced for easy installation purposes.

The usual drywall can be used for dry locations, while humid areas of the house require moisture-resistant sheets, also named ‘green board’ for its green face paper.

Another specialty is fire-rated drywall for high-fire resistance in areas such as garages and flexible drywall, a thin panel used for curved structures.

Difference between Drywall and Plaster

Plaster (as in plaster of Paris) is an old construction method commonly used until the 20th century as a form of interior wall finishing.

The wet plaster used to be repeatedly slathered over numerous wooden strips called laths.

It would then harden to form walls and ceilings after a long drying time and needed redoing to achieve a perfect finish.

This technique, regardless, was excruciatingly labor-intensive, time-consuming, and required excellent skills.

Drywalls are a godsend; interior construction that almost took a month could be finished in a few days with added advantages of excellent durability and moderate pricing.

Now that you know enough about drywall, let’s return to priming it.

Can You Paint New Drywall without Primer?

You can paint new drywall without a primer, but it’s not worth trying.

Painting without priming will often require more effort and primer quantity.

The flat paint will not adhere well to a rough, un-primed new wall, making the job more demanding, time-consuming, and expensive.

When Do You Need to Prime Drywall?

You must apply the primer after the drywall is installed, sealed, dry, and ready to go.

Be sure to address any potential issues before you start adding the primer. Like if you need to fill in any small cracks, nicks, or marks, it’s best to do so before applying the primer.

Also, dry out any potential trouble spots, open the windows, and switch on the fan to ensure the room is well-ventilated.

If you see an area that’s very slow to dry, investigate to see if the drywall is over the pipes. Adding extra insulation now can save you from having to repaint later.

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How to Prime and Paint Over New Drywall?

When it’s time to prime drywall, everything begins with suitable undercoat primer paint and paintbrush to do the job.

Getting some floor covers to protect your flooring from dripping primer and paint is also helpful.

Also, you will need painter’s tape to edge off areas outside the drywall and the right clothes – that you do not mind getting paint on them.

Step 1. Cleaning

Start by cleaning and preparing the new drywall. This is not that difficult if the drywall is new because it should already be in pristine condition.

But if it’s an old unfinished drywall surface, ensure that any dirt, grime, or oily covering is removed so that the wall itself is exposed and ready to be primed and painted.

Also, go over the drywall to ensure that any changes you need, such as holes for outlets, have been cut.

Step 2. Priming

In this step, you should create a frame on the wall where the rest of the primer can be applied.

So, use a brush to paint the edges of the walls, floor, and ceiling. While doing so, care that you do not create any brush marks when applying the primer.

Step 3. Prime again

Once you have created the frame, use a roller to apply the remaining primer to the wall (inside the frame).

Run the roller up and down the wall until you have covered it all with the primer.

If the wall is too high to reach, use a drywall stilt or a ladder for priming.

Step 4. Inspect and dry

Once complete, step back to see if you have missed any spots. Cover such areas with a new application.

After you have inspected your work, let the primer fully dry.

After a couple of hours, check to see if the primer is dry by touching a small area.

If you notice color differences that may indicate the primer is still wet, it is best to err on the side of caution.

Run a fan to circulate the air and dry the primer faster if it’s taking more time.

Step 5. Paint the Drywall

Once dried, you can apply the new paint in the same manner as the primer.

This means creating a frame of new paint along the edges with a brush, then filling in the rest with a roller.

Once the first coat is dry, check to see if you need another coat of paint. If required, apply one more coat of paint.

Generally speaking, a single coat of primer and two coats of paint provides maximum protection for the drywall while conserving the amount of paint you use.

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How Many Gallons to Prime New Drywall?

Generally, the rougher the surface, the more primer you will require to cover the sheetrock completely.

I have worked with around half a dozen primer brands over my lifetime and found these facts…

About 1 gallon of primer will help you cover approximately 225-275 square feet of new drywall surface under most natural conditions.

For smooth surfaces (like old drywall that has been primed or painted before), 1 gallon of primer tin will cover around 300-350 square feet of the surface.

Based on the above, 5 gallons of primer will cover around 1150 square feet of new unfinished rough drywall area for most contractors and painters.

However, if you are priming smoothened drywall, you can cover around 1650 square feet of area with 5 gallons of primer.

Use this as a rough estimation when buying the number of gallons for your new drywall.

If unsure, you can always double-check with the primer manufacturer. The recommended coverage is many times printed on the primer/paint can you will use.

Drywall Sealer vs. Primer: Is There Any Difference?

You may hear about drywall sealer and primer and wonder what the difference is.

After all, many painters will use both terms as if they are the same.

However, in terms of products, usage, and benefits, drywall sealer and primer are pretty different.

Sealer

The primary purpose of a sealer is in the name. It seals up the tiny openings on the surface of the drywall.

The result is that when finished, the surface is now adequately protected and provides an even surface for the paint to stick.

You can purchase sealers in a variety of pigments or choose clear versions.

That said, keep in mind that some sealers are not designed to have additional coats of paint added to the surface.

So, check before you purchase to ensure that you can add the paint you want. 

Primer

The primary purpose of a primer is to provide a sticky surface for the paint to adhere to.

They are similar to paints as they include many of the same pigments and fillers, but they are also intermediary coats that are not designed to stand on their own.

In other words, they need the paint to cover their surface because it will be uneven in most cases. The uneven appearance of a primer is not really an issue when standard coats of paint cover it.

But the advantage of tinting means that to get the desired look (when you complete your painting), fewer coats will be needed.

Primer Sealer combination

You may often see a two-in-one combination of drywall sealer and primer in one product.

Called primer-sealers, these products help to smooth out the textures while sealing the drywall itself. But still, their primary function is to create a surface sticky enough for standard paint to apply.

They are well suited for use over walls that may have significant differences in existing colors. By creating a new surface of primer or sealer, such differences in colors can be smoothed out considerably.

The combination of primer and sealer is also very effective when used under wallpaper.

You can even tint the combo so that it blends in well with the paint you are about to use. This saves you time and money as fewer coats will be necessary.

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Self-Priming Paint vs. Tinted Primer: What’s Better?

Before choosing the right type of paint primer for your new drywall, it’s also essential to understand the differences between these two terms.

Self-Priming Paint is an all-in-one product designed to provide even coverage without having to add a third coat.

The advantage of self-priming paint is that it does contain PVA (I will discuss more on it in just a second) so that it will stick to the surface.

However, if you have purchased a specialty paint or want to use the paint already lying in your storage, adding a tint to the white primer may be the best option.

But be aware – with the tint, it will not be the same color as the paint you use, but it should be close enough that it will not show through the topcoat of paint you apply afterward.

What are the Benefits of Using PVA Drywall Primer?

The primary ingredient of primer is polyvinyl acetate or PVA. This is basically the same as the carpenter’s glue.

When the PVA is applied, it seals up the surface of the drywall to prevent any leakage from affecting the paint. Plus, it provides good surface adhesion, allowing the paint to stick and take hold for longer on your sheetrock.

One of the most important benefits of using a PVA drywall primer-sealer is that it helps reduce the number of expensive topcoats you will need to apply to your drywall, which means you can save good money by applying fewer paint coats.

Easy sanding

Additionally, the drywall primer, when applied, makes sanding the surface much easier for smoothening the walls.

In other words, when you have appropriately applied the primer to your drywall, you save a lot of time and energy while sanding the surface compared to the surface that’s not primed.

Smooth surface

Another benefit of applying a PVA primer on your sheetrock is that it smoothens the surface and eases the painting.

The new sheetrock is often dry, and when not primed, it sucks the moisture in the paint instantly when you apply it with a brush or a roller.

This makes you apply more effort to glide the paintbrush smoothly along the surface.

But when primed with a high-quality sandable PVA primer, the surface is already smoothened, which makes you glide and spread the topcoat very quickly.

This also means you will get a flawless, finished, smooth surface when you have completed mudding and painting the drywall.

What is the Best PVA Primer Sealer to Use on New Drywall?

There is a wide variety of PVA primers available to buy online. These are specially designed for drywall coating and come at an affordable price range.

Some of the best brands I have ever worked with include Glidden, Kilz, Behr, Valspar Pro, Benjamin Moore, Zinsser, and Sherwin Williams.

When buying, I usually prefer to look for a primer that can be sprayed, brushed, or rolled on.

Also, it should be available at a generous price, as investing in something overpriced does not make sense since they all need to go under the topcoat.  

Spraying primer on new drywall is what I generally prefer; you can do it just as you do with spray paint.

But before working on your drywall, clean the dusty surface and pick the correct spray gun. Depending on the surface, you may also require “back rolling” to create good adhesion.

As long as the sealer product can seal up the wall perfectly well and allows me to apply a uniform topcoat, it’s a perfectly fine product for me.

For all these reasons, I typically use KILZ Adhesion High-Bonding Interior Latex Primer/Sealer, which works amazingly fine for me.

I never had any issues working with it, and being available at a great price on Amazon; this best drywall sealer is my top choice among all.

A few other features that come with this drywall primer are:

• Perfectly seals up new drywall and other surfaces
• Unlike traditional water or oil-base primers, it provides unique adhesion
• Dries to touch within 30 minutes and makes the surface ready to recoat in an hour
• It can be easily used under epoxies, lacquers, and products containing Xylene or other solvents

Not to mention, KILZ has been making premium primers and paints for over 40 years now. And I am pretty sure you can never go wrong when choosing their products.

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The Bottom Line

With all the above information in mind, it’s clear that using a high-quality primer that comes at an affordable price is essential when you want to paint your drywall.

To get the right finish and shine, consider picking a sandable Polyvinyl Acrylic primer-sealer that can be used with a brush, roller, or spray gun.

When done right on your new drywall, you will be amazed to see how perfectly it offers the shine and finish you have always desired.

If you still need help applying primer to your new drywall, you may check the quick video guides available on youtube.