How many coats of primer short answer: all unfinished surfaces like new drywall need one coat of primer: it seals the pores. Repainting a wall? If the color changes are not drastic, no primer is required!
Quick Menu: Primers come in 3 basic flavors: latex—oil—shellac (these clean-up with water—mineral spirits—alcohol). In most cases, apply one coat of primer. All can be sanded for a nice smooth start.
If you just want to see them quickly:
- For new (unstained) drywall: One coat of primer. You don’t need stain blocking power, so use this good but inexpensive drywall primer.
- For re-painting walls, trim, etc: One coat of primer unless the new color is the same (or similar): the go-to primer is this medium-power primer. when changing from dark to light colors.
- For unpainted wood: One coat of the right primer: (see caution below about latex primer and wood). Use a medium-power oil-based primer for most woods.
- For nasty stains, ink, and worse: One coat of the big dog primer: this high stain blocking shellac Have rubbing alcohol ready for clean-up. Ah, B-I-N. Is there anything you can’t do? No, there is not.
We were asked to discuss how many coats of primer are needed in interior painting situations, but the question rarely comes up for us. Here are the basics. BTW, actually painting the primer coat can be very fast as it flows better than paint (Plus in the end 3 coats is faster from a quality point of view). Be sure to read the shortlist of what primer does for you just below the skinny.
♦ General rule: All unfinished surfaces need a primer. It will save you time and money, and look a whole lot better, but how many coats of primer should you apply? Almost all of the time, you only need one coat of primer! Not what they told you? Don’t listen to non-painter sites. They hire English majors.
♦ How long does it take for a primer to dry? Even the oil-based primer listed below dries fast: much faster than oil-based paint. Latex primer takes in average 30 min to 1 hour, and oil-based primer up to 3 hours. How long the primer takes to dry depends on the humidity and temperature of the room (cold and humid longer, obviously).
Caution: Water-based primers on untreated wood has, can, and will raise wood grain. Put the right primer on wood. Why? Tree rings alternate hard/soft and the soft rings grab more paint and expand, and dry that way: a smooth surface becomes bumpy. Oil-based primers are preferred for almost all wood.
How Many Coats of Primer:
- How many coats of primer on new drywall? One coat of primer, if you use a quality primer (see related post above or just see it here for what we use: excellent primer at a great price). Be sure to read about the toxins in paint and primer. We also buy the Benjamin Moore Ultra-Spec (a contractor line): this is 5 gallons but keeps a long time (never let it freeze!) We use VOC-free paints or wear respirators.
- Glossy paint: One coat. Was it last painted with oil or latex? Major huge important. You must find out. The test is below*. Remember: latex paint will NOT STICK to an oil enamel surface. (This is not what oil primers are). If in doubt, you’re safe with Stix. It sticks. New to the world of primer, Stix is our go-to bonding magic. (BTW: You should still sand glossy finishes every time anyway). PS: Stix is made by Benjamin Moore (read about it on that website). Alternately: use a de-glosser, then prime with the Kilz Premium just below.
- Walls—changing wall color: One coat. Prime only when making drastic color changes (or when applying reds and yellows). Ask us in the comments or call a paint store about painting over dark colors with light colors or vice versa but yes you need primer. Our main latex primer is Kilz latex primer, a.k.a. Kilz Premium. Tip: reds cover best with gray primer. Yes, gray. Not making a big color change? No primer needed. Can you still use Kilz paint colors with primer? Sure.
- Paint and primer in one? One coat. While it may contain some stain blocking elements, we don’t like it. Read our post on it. It’s slower than two normal coats (you have to keep checking to make sure your coat is thick enough). And we use the same tools you should use. (Crappy tools make you hate painting!) It is also more expensive in the end if you count time as money. We do. Kilz paint are considered to be the best value: Kils paint color choices are decent. See the photos below for how it often fails.
- Bathrooms. One coat. Use a primer for high moisture areas: From Benjamin Moore—the famous Auqa-Lock. We don’t use this primer for half-baths—just the main latex primer unless there is a shower stall. How many coats of primer in a bathroom? one coat of primer is enough with a good quality primer.
- Green board drywall: One coat. Treat just like the drywall above. This is also called drywall primer sealer, or drywall sealer.
- Painted wood. One coat. Probably doesn’t need a primer (see about glossy trim and see about color changes above). But we do spot prime chips and worn spots with an oil primer for pine which is the most common trim wood, and the one that bleeds the most.
- Unpainted wood. One coat. Yes, always use a primer, and almost never use latex. We use oil primers with disposable brushes (actually we try to keep the old brush in the can!). If you want a smooth finish, fill the wood grain, you need to create a flat surface with a grain filler**. Paint and primer are not designed to fill holes. Oak grain probably needs a filler, but maple or pine could look fine with a coat or two of a coat of a decent oil primer. In any case, we mainly use this stain-blocking primer. Our latex choice would be Kilz Premium.
- Stains. One coat of primer if it has stain blocking power, but it depends on the stain. We have a whole post about putting paint over stain. For water stains etc, all the tough stains, go jump to the shellac (alcohol-based) primer because you know it the problem will disappear. B-I-N to the rescue. Check you work when dry. Did stains bleed through? A 2nd coat (spot priming) may help.
Other less often asked about:
- Floors: One coat. See an entire post just about how to paint floors and another on the types of paint available.
- Mold: One coat. If you just want the right stuff it's easy, but if you want to read about mold, here is a close look.
- Particleboard: One coat. If you must. Use the same primer as for unpainted wood.
- Plywood: One coat. Watch a video from a real nerd (he’s smart) about the enormous differences in plywood. Some are cabinet quality. Some for sub-floors. Use the same oil primer as you would wood. Ceiling sealing. Ha ha. Dear deer.
- Masonry: One coat. Easy…masonry primer. Use a block filler if you want to avoid the institutional look.
- Metal: One coat. There are metal primer Rust Scat by Benjamin Moore. You should not paint metal without it. Don’t drop a can on your driveway like bradthepainter. Oh yes.
- Tile, stone, laminate, etc. Zero. Don’t paint it. Trust me on this. We’ve known each other a long time.
- Smoke damage, stinky odors: One coat, if you use the big dog of primers. There is a primer for this. Cigarette smoke is notorious. It may take more than one or 2 coats to un-stink-ify. I have had sucess with Kilz Oil: wear a respirator-ugg! For a water-based product, go Kilz again.
- Wet anything: Oi vey, don’t paint anything unless it`s bone dry. Try fans, heat etc. If you must paint something when wet, use an oil-based primer and try to work the primer vigorously into the material. Again, not recommended. I have never tried swimming pool paint, but it may help.
The only time we would ever ponder how many coats of primer to use is when our first product did not contain enough sealants (resins, etc) and some stains from the old surface managed to bleed through. Even so, sometimes, a primer will show stains when it is dry, but it has, in fact, stopped the stain right there: it will not allow the stain to bleed into the finish paint. Easy to test for this. When in doubt, B-I-N is the answer. B-I-N is the answer.
We had a reader write and ask why the dark areas near her radiator were bleeding through. Answer: Wrong primer. Some primers just seal drywall (and they are not very expensive). Others seal out nasty water stains and magic marker spots. Those are hard to seal, so you have to hit those spots with the nuclear option. Explained next.
The shortlist to know about primer:
- Primer works by filling porous areas of your surface—not all areas are the same because they look alike.
- Why not just use old paint as a primer? Because paints are not stain-blockers/pore-sealers. If you prime new drywall with regular paint (never use exterior paint inside), you will always see the taped seams through the topcoats. See the first bullet point above.
- Even skimmed coat walls need a primer to achieve a uniform top-coat look. (Fine with one coat of a good drywall primer.)
- Water-based primers on wood can ruin it. Read the bullet point above about ‘unpainted wood’.
- Primers do not fill holes or grains in wood.
- Primers apply faster than paint and you don’t need to care how they look so you can go fairly quickly.
* To re-paint glossy trim you need to know if it was painted with oil-based paint or not. Test it with acetone or in a pinch, rubbing alcohol. Put the solvent on a cloth or paper towel and rub the paint. Does it get gooey? It is latex. No goo, oil. Painting latex over oil: sand like a banshee (scratch every bit to create a bond for new paint), or use the Mother of all Toxic materials, de-glosser. This stuff evaporates like water on a red-hot skillet. Nasty. Wear your respirator!!
** Wood grain fillers really work. There are 2 sizes but if you are doing more than a small piece of furniture, get large to save money. This does not fill large holes. You need wood filler for that.
This is a generic one coat paint of brown semi-gloss rolled onto some primer. The brown looked fine when wet. Now look:
Did we leave anything out? Let us know in the comments!
How many coats of primer on wood? Somehow people got the idea you need more than one coat of primer on wood.