With fresh drywall, the substrate actually absorbs a coating really well, like a sponge. However, because it absorbs so well, without a primer coat, you'll experience uneven coverage, especially along drywall seams. This means you'll need to apply more paint to finally get an even coat.
Paint manufacturers nearly always recommend a primer. Yet it would be hard to find a do-it-yourselfer who wants to prime if it's not necessary. Bare, previously unpainted drywall, though, is one of those surfaces where the answer is unequivocal: Yes, priming is always needed.
Use primer when drastically changing a color
There is no need to prime if you are applying a slightly different color, but anytime you are making a big change, it is a good idea. The last thing you want is to go through the work of painting only to see the old color showing through.
The simple answer is that primer is not always necessary, so it's possible to save money by omitting it. However, in many cases primer will actually save you money because it reduces the number of more expensive topcoats you will need to get beautiful, lasting results.
Primer will hide the old color so it won't compromise your new shade, and it helps the new color to adhere for solid and even coverage. Self-priming paints will not provide sufficient coverage when there is a drastic color change, so if you don't you prime the walls you'll probably need a third coat of paint.
On new drywall, you will use 3 coats of the finish material instead of a primer coat plus 2 coats of finish. Most projects where you're going over a previously-painted surface do not require the use of a primer.
A minimum of two coats of PVA primer is necessary when painting new drywall in order to prevent the paint finish from looking splotchy and uneven after drying. New drywall is like a sponge, and it's better to let it soak up inexpensive primer than expensive paint.
You probably don't need a primer. If the current wall is smooth, clean and covered with the same type of paint (both are oil-based for example), you can head straight for the paint. You need to fill holes, spackle and sand*, maybe even cut a new piece of drywall in to the existing wall.
Without a proper primer you may lose adhesion or a surface contaminate may bleed through. Or you may need to apply 3-4 coats to block out a deep color. Check these factors before you apply paint or paint and primer in one directly to the surface.
Typically, contractors use a primer, then two coats of paint—the primer to seal the surface and improve paint adhesion and the paint to provide color and protection.
Primer is often referred to as a base for Foundation or a Foundation primer. They are most commonly used to achieve a controlled matte finish. It isn't necessary to use a Primer before foundation, yet there are many benefits to adding this product into your makeup bag.
Typically you can use almost any white paint as a primer, but there are a few things to be mindful of. I recommend using a can of flat or an eggshell white paint as primer.
Use It as Base Coat or Primer
“If you use it up, you will probably save yourself from buying more of what you're putting on the walls, and there's no need to bring it to a paint recycling center,” Fresina notes.
It's not recommended. The general rule of thumb is to properly tape and mud drywall joints before painting. Not only will skipping this step lead to unattractive walls, but it is also against building codes. So yes, mudding the drywall before applying the first coat of paint is a necessary step.
Water-Based and Latex
Most drywall primers are water-based products, and there are a lot of benefits to these primers. First, they're low-VOC, so breathing around them is safer than oil-based primers. Also, they're inexpensive and spread easily. They seal fresh drywall well, and they're a great base for latex paints.
If the wall surface is smooth, you can skip the primer step. However, if there are textured areas or wrinkles on the wall, you'll need to prime it first. If your wall has been previously covered in wallpaper, you should definitely plan on using a primer before painting.
Face primer is essential to any great makeup look — whether you're rocking a full beat or just a few dabs of concealer. And while a great skincare routine can work wonders for making sure your makeup wears flawlessly throughout the day, primer is the real key to getting your makeup to perform the way it should.
This is probably the easiest and most obvious choice: you can use your regular day moisturiser as a primer replacement. It's great is the product contains humectant and emollient ingredients, such as glycerine, hyaluronic acid, or aloe vera leaf juice.
Chalk Paint
Like mineral paint, you also don't need to use a primer beforehand. It's another paint type that binds to just about every material or surface, both indoors and outdoors. If you use chalk paint to paint furniture without sanding, adding a top coat finish is recommended.
Spackle is a substance that tends to be more porous than the wall around it. This means that painting over spackle without primer will result in a dull spot that doesn't match the rest of the wall. Therefore, it is extremely important to prime the spackle spot prior to painting over it.
This process is called “spot priming.” If you already have primer, simply use a little primer on those patch areas. It is not necessary to prime the whole wall if you're using the same or similar color. When the “spot-prime” areas are dry, you can paint the wall normally.
Do you always need to prime drywall before painting? It's important to prime after new drywall installation. The new surface will be porous and will absorb the color of the paint. Primers will also cover the joint compound and provide a good base for texturing or painting over skim-coated drywall.
You're painting unfinished drywall or plaster.
Two primer coats are recommended in this scenario because much of the first primer coat will be soaked up by the wall; the second coat will replenish any primer absorbed by the surface and hide any flaws in the wall.