The whole reason for painting your home is to give it a fresh look and maybe spruce it up with a fresh color of paint to give the space a new look. So when you choose to go for a textured or smooth wall, you most likely want long-lasting results. When it comes to drywall since all the joints are taped and nailed, if you paint over it, it will be difficult to get an even coating.
So, yes. You do need to prime your drywall before painting to ensure that the paint doesn’t wear out faster, and priming also helps to protect the surface of the wall you’re painting. Drywall can soak up a lot of paint so if you don’t prime it, you’ll end up applying several coats of paint before giving a uniformed look. But if you prime the surface first, you can end up using less layers of paint, especially if you use a tint primer and also prevent the growth of mold.
Why drywall primer is necessary
New, freshly finished or bare drywall is difficult to paint directly because the surface has 3 different surface textures and each has its own level of absorption.
- Heavily sanded drywall, especially around the mudded seams may have a fuzzy scuffed surface that will tend to absorb a lot of paint.
- The taped and mudded seams and the screw holes covered by the drywall can also absorb the paint.
- Drywall is faced paper and paper is very porous which means it can absorb a lot of paint.
So when you apply paint directly on new or finished wallboard, all these different levels of absorption will give you a mottled streaked look with blotchy areas. This unevenness will only show after applying many layers of paint and depending on the glossiness and color of your paint, you can use 2-4 coats of paint before you get an even surface. For you to achieve a uniformed appearance with the final coat, it’s better to first use a quality primer that is less expensive than using multiple coats of latex paint.
Different types of wall primers
Pigmented shellac primer
Very versatile. Can be used on walls, metals, plastic, plaster, or wood.
Works well on interior paint jobs and as a spot exterior primer.
Can block stains on your wall.
Dries up very quickly, highly adhesive, and can be used with both oil and latex paints.
Used on both metal and wood. Works well with dry, painted, and new wood.
Need to be used with mineral spirits to thin it up.
Not very safe because they emit volatile organic compounds that are harmful to humans.
Takes a long time to dry up like 24 hours or more.
Very effective on both interior and exterior surfaces.
Latex or acrylic primer
The most versatile. Can be used on drywall, woodwork, plaster, painted metal, and masonry.
It contains little to no VOC compounds.
It’s water-soluble and it dries faster.
Has an impressive cracking resistance.
Why is it important to prime before painting your drywall?
Primers seal the drywall
The main ingredient in drywall primers is polyvinyl acetate which is the same material you’ll find in carpenter’s glue whose main purpose is to seal the drywall paper. Without this adhesive substance, water-based paints with a latex binder will soak unevenly into the porous material creating botches and rough areas.
Uniformity in sheen and color
The seal that PVA primers leave on the surface of the drywall gives the paint a uniformity of its color so it doesn’t surprise you with a different end result. However, if you don’t use a primer it reduces the pigment ratio of the topcoat which leads to too much pigment soaking into the drywall giving you a lighter final color than it’s supposed to and the final sheen may also be chalky and ununiformed.
Better paint adhesion
The best thing about primers is excellent paint adhesion. They’re like glue that will help the paint to stick onto the surface and this keeps the paint intake for a much longer time. It also helps to show off the color because it’s not absorbed by the drywall. If you skip priming the paint might peel especially in humid conditions and because of lack of adhesion, it becomes difficult to clean once the paint has dried. The paint will wear off if you try to clean fingerprints or dirt and can even appear dirtier.
Covers imperfections better
Primers act as a seal that will not only block the absorption of paint into your drywall but also cover flaws.
Drywall undergoes repair and leaves tiny blemishes that can be covered with primer. It helps to insulate the wall and protect the drywall against damage.
When you want to paint your drywall, you must use a quality primer to give you the right finish and shine you wanted.
How long after priming can I paint?
Most latex primers dry within 30 minutes to 1 hour but don’t paint your wall until the primer has dried completely which can take about 3 hours.
How many coats of primer do I need for drywall?
You only need one coat of primer and 2, 3, or even more coats of paint to give you good coverage depending on the color. On a wall that currently has been painted, you may not need a primer coat.