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The 3 Best Stain Blocking Primers

best stain blocking primer

Water stains, nicotine stains, knots, children (markers, crayons, etc.), pets, they are all out there to make your house look a mess. You’re not powerless to fight them though. For painted surfaces there are some incredible stain blocking primers that can make these stains virtually disappear.

This is not going to be a consumer reports type post, but rather a Craftsman Blog reports type post. I’m sure there are a lot of other stain blocking primers that will work very well, but I’m going to give you my favorite primers that I have had the best results with in my career and what I use on a regular basis.

Why do you need a list of the top 10 stain blocking primers when one of these three will take care of just about any situation? Seriously, these primers have yet to let me down and I know they’ll do great for you too.

What is Stain Blocking Primer?

Knot holes bleeding through paint

Some primers are meant for simple preparation of the surface in order to help the paint get a good hold and last for years. A stain blocking primer is designed to provide more robust coverage and prevent stains from bleeding through newly applied layers of paint.

Typically, these are oil-based primers or alcohol-based primers that come with the extreme stain blocking that you need. Latex paints have stain blocking abilities, but in my experience they only provide marginal coverage compared to their solvent based cousins.

Certain stains will appear to be covered upon first application, but then bleed through the paint months or even years after application. At that point you need to prime and paint all over again so using a stain blocking primer first is always a good idea when trying to paint over any of these items below.

  • Water Stains
  • Marker or Crayon
  • Nicotine Stains
  • Knot Holes
  • Old-Growth Wood
  • Certain Species of Wood (Redwood and Cedar)
  • Pet Stains
  • Wood Stain
  • Covering Old Shellac

All of these items will need some level of stain blocking primer to get adequate coverage. I typically start with the easier to apply and less expensive stain blocking primers before moving up to the heavy duty ones only when necessary or when experience has taught me to start at the top.

kilz 2 primer

Kilz 2

A name intimately associated with stain blocking primers is Kilz since they have been in the game a long time. If you insist on using a latex stain blocking primer then this would be my choice. It is easier to use since you get the water clean up you want, and light to moderate stain blocking. This might work for crayons and light nicotine stains, but it is not particularly powerful for most stains in my experience. It’s a good place to start, but certainly not my go to primer.

kilz exterior primer

Kilz Original

This is an excellent oil-based primer for blocking stains both inside and outside. The oil-based formulation gives it a vastly improved stain blocking ability in my experience. I’ve used this on window restoration projects or to prime cedar siding and knot holes with great success and zero bleed through. You can use it to block most tannin bleed, graffiti, smoke, fire and water stains as well as sealing pet, smoke and food odors.

bin primer

BIN Shellac Primer

For the worst stains and bleed through this primer has never failed me. It is a denatured alcohol based primer the uses pigmented shellac to hide stains. That’s fancy paint speak to say that nothing get through this primer. I’ve used this to defeat heavy tannins on old-growth woods or covering old finishes that can sometime bleed pink through other primers. It is only for interior and “spot” exterior use so you can’t fully coat exterior projects with this especially in hot climates which does limit it unfortunately. You also need denatured alcohol to clean your brushes, but its stain blocking power is unlike anything else I have seen.

How To Use Stain Blocking Primer

If you get into a situation that won’t cover with a traditional primer then before you paint, apply a coat of one of these primers. If after 24 hours you don’t see any bleed through then you should be good, but you need to give it some time to fully dry before assuming your coverage was successful.

Wood tannins in old-growth wood, knot holes and woods like cedar and redwood can take much longer to show through so you need to assume a stain blocking primer is needed. Skip it at your own risk and you’ll end up like the picture above of a cedar ceiling that wasn’t primed properly.

Sometimes you’ll see a pink color bleeding through your primer. You may wonder where the pink is coming from. This is wood tannins coming through and it almost always requires a shellac-based primer.

For exterior projects that need heavy stain blocking where you can’t use the BIN primer I would suggest using multiple coats of the Kilz Original to try to resolve the issue and only spot treating knot holes or trouble spots as they show up with the BIN primer.

Stain blocking can be a challenge and I hope this post has helped clear up some of the confusion on this topic. I hate seeing homeowners get analysis paralysis so I wanted to make it really simple by giving you three easy choices that are relatively easy to find in most stores.

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6 thoughts on “The 3 Best Stain Blocking Primers

  1. I believe I know the answer, but reaching out to experts to try and see if there’s a way around this. I used Bin synthetic shellac, which was water-based, supposed to act like the oil base product on an entire room of bead board on the lower half of the walls. We primed entirely and then hit the knots again, a second time, with the synthetic shellac before applying 2 finish coats of satin based off white paint and installing all the woodwork with arm rail. The boards now are yellowing in certain places bleeding through not only some knots, but some panels are yellowing and some aren’t, so it now looks crappy and noticeable around the entire room. Do I have to strip all this work or can I try once again to use a different type of bonding primer to hide the bleed and yellowing, then paint over it again? I know you’re not supposed to put oil base over water base. without stripping it down to bare wood. Any thoughts would be appreciated.

  2. On the advice of a painter with 30-years experience, I used Bin to prime the exterior of my house in central Florida about 20 years ago. It gets pretty hot and humid here. Have had zero problems with stains, peeling, flaking or anything else, and the top coat still looks good, while nearby homes have been painted two or even three times in the interim. Not sure why the manufacturer recommends ‘spot only’ exterior use, but it sure worked well for me as exterior primer. I don’t use anything else now. Expensive, but you get what you pay for.

  3. Kilz seems to have discontinued the quart-sized original oil based primer. So the gallon sized it had to be. It has dried much slower and remained “sticky” for days after. I sanded after a week and it still doesn’t feel fully cured. It’s almost as though the formulation has changed.

    I have an unusual real-time experiment going on. One side of a sash was primed with Kilz original from a quart. The other from the new gallon of Kilz original. The new Kilz lays down with a feel similar to Kilz3 water-based primer. (I primed a different sash with Kilz3 from a quart to test for future sashes.) I haven’t tried sanding the Kilz3 but am told that it can be sanded if necessary after it is fully-fully cured.

    Question – Has Kilz recently changed the formulation of Kilz Original? Note: The label does not indicate low VOC but the gallon doesn’t seem to have as much odor.

  4. I’m an Architect living in Virginia Beach. A bathroom ceiling in my home has water stains along the exterior wall. I applied three coats of BIN shellac primer, and sanded each coat with 600 grit, then painted with Sherwin Williams Emerald white. The stain is still visible.
    The author omits advise we’re all familiar with, quality results require a quality professional. Whenever you want to cover a stain, hire a professional painter. They customize paint to suit the specific condition.

    1. You might just be seeing the flashing from spot priming. Bin shellac has an off white tint. Almost yellowed. If you only coated the ceiling once after the stainblocker, that could be why. You would need to prime the whole ceiling for a uniform appearance and or spot prime with ceiling paint in that spot and then double Coat. The other issue is if you created a texture difference the light will catch it and give the appearance of stain being still “visible”. You’ll need to skim the areas with mud to hide that now. Then prime and repaint. From my experience. BIN Shellac, even in thin coats is a one and done for water staining repairs. I often just dust the stain with the rattle can and that’s good enough. Strong stuff.

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