Stains coming through white painted wood stair risers

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jimmo
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Stains coming through white painted wood stair risers

Post by jimmo » Wed Oct 18, 2017 2:39 pm

I have stairs with dark stained treads and risers painted white. The painted white risers are some type of wood, probably pine. About six months ago I noticed dull yellowish stains coming through the white paint. You can't wipe it off or clean it off as it's coming from the inside out. The staining is generally where there appears to be knots in the wood. So my thought is that the risers were painted before the wood fully cured and dried and the knots are slowing seeping out moisture that's coming through both the primer and topcoat.

My initial thought was to get some stain blocking primer and repaint the troubles areas. So in the last 6 months, I've now twice primed over the stains with Killz premium primer and then top coated. Within a few weeks the stains came right back, just the same looking as before. Any ideas on a permanent fix? How do I keep the stains from coming back through? It's 4 or 5 spots on different stairs and always round stains appearing to originate from the knots of the wood.

Here's a picture of a similar stair layout. Not mine, but just to give you a visual of the situation.
http://temptingthyme.com/wp-content/upl ... almost.jpg

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Sandtrap
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Re: Stains coming through white painted wood stair risers

Post by Sandtrap » Wed Oct 18, 2017 3:16 pm

Use Oil Base Kiltz stain blocking primer, the most toxic smelling one. It is for tannin. I'm not sure if they still sell that type so you will have to get alternatives, shellac, etc. It will block the tannin from redwood, pine, cedar, etc. It will take a lot of coats to get the tanin to settle down. Wait a while, a week or more, between coats. Do not sand the wood or you will open the cells of the wood and release more tannin. If it has water based primer on it, then a light sanding will help the new primer bond but don't go down to the bare wood. Water based primer will not work very well.

I have done quite a few extensive renovations on older homes that had entire walls and stairs of redwood, pine, or cedar. It is difficult but can be done with the right oil based primers and techniques. And, yes, the knots are the most troublesome spots.
Again, do not sand the knots as it will just release more tannin.
Good luck.
j :D
Last edited by Sandtrap on Wed Oct 18, 2017 3:19 pm, edited 2 times in total.

renue74
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Re: Stains coming through white painted wood stair risers

Post by renue74 » Wed Oct 18, 2017 3:18 pm

It's tannin staining. You'll need to use a shellac or oil based primer for stubborn stains.

Visit a Sherwin-Williams or Ben Moore and tell them your issue. They'll provide a better primer than what you'll get at the big box stores.

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lthenderson
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Re: Stains coming through white painted wood stair risers

Post by lthenderson » Wed Oct 18, 2017 3:21 pm

jimmo wrote:
Wed Oct 18, 2017 2:39 pm
I've now twice primed over the stains with Killz premium primer and then top coated.
Killz is a cheap primer sold at Walmart and big box hardware stores. I would upgrade to a decent primer and try again. I personally use Sherwin Williams Premium Wall and Wood Primer for that type of application. It lists for almost five times the price ($48/gallon) of Killz but I've never had tannins bleeding through the primer either.

BW1985
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Re: Stains coming through white painted wood stair risers

Post by BW1985 » Wed Oct 18, 2017 4:45 pm

Does this happen to poplar? We just painted and installed our risers so I hope not. :confused
"Squirrels figured out how to save eons ago. They buried acorns. Some, they dug up, for food. Others, they let to sprout, in new oak trees. We could learn from squirrels." -john94549

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mrc
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Re: Stains coming through white painted wood stair risers

Post by mrc » Wed Oct 18, 2017 4:51 pm

BW1985 wrote:
Wed Oct 18, 2017 4:45 pm
Does this happen to poplar? We just painted and installed our risers so I hope not. :confused
Nope. This is an issue with SPF (softwood) knots.

Zinsser B-I-N stain blocker (shellac) works great for this.
A great challenge of life: Knowing enough to think you're doing it right, but not enough to know you're doing it wrong. — Neil deGrasse Tyson

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Sandtrap
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Re: Stains coming through white painted wood stair risers

Post by Sandtrap » Wed Oct 18, 2017 5:03 pm

mrc wrote:
Wed Oct 18, 2017 4:51 pm
BW1985 wrote:
Wed Oct 18, 2017 4:45 pm
Does this happen to poplar? We just painted and installed our risers so I hope not. :confused
Nope. This is an issue with SPF (softwood) knots.

Zinsser B-I-N stain blocker (shellac) works great for this.
+1

jimmo
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Re: Stains coming through white painted wood stair risers

Post by jimmo » Wed Oct 18, 2017 5:40 pm

Thanks all! Sounds pretty unanimous that I need to get some decent oil based primer or shellac. Hopefully that takes care of it because every time I go up the stairs it bugs me. Wife claims she didn't even notice until I mentioned it.

shanefairman
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Re: Stains coming through white painted wood stair risers

Post by shanefairman » Wed Oct 18, 2017 6:44 pm

As others have stated you really want to use a shellac primer on pine knots. I have used Zinsser BIN and it's a great product. Honestly any shellac based should be fine.

As others have noted that the cheap oil based Killz is a great primer for stain block and sealing in odors as well.

Shellac based primers use denatured alcohol as the solvent. The vapors are quite nasty and proper protection is required. Even in a well vented area a full face respirator with organic solvents filter is good idea. In some environments a positive pressure fresh air respirator would be required.

Also denatured alcohol vapors are flammable so take extra precautions.

A good painter would have spot primed the knots with shellac before priming the rest of the riser. Shellac primer can be used on the whole surface but is best for just spot priming unless absolutely required. Shellac can be use indoors on walls and ceilings but shouldn't be used on floors. Shellac can be used outdoors but only as a spot primer never as a whole surface primer. Shellac is vapor impermeable so if used on a whole board outdoors will eventual bubble and fail as vapor pressure can build between the wood and shellac.

Stay safe.
“You must not only think for yourself, you must plan for yourself, and you must plan ahead, and you must live up to these plans. You must know exactly what you want to do.” -George Carlin, Boston Rant

BW1985
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Re: Stains coming through white painted wood stair risers

Post by BW1985 » Wed Oct 18, 2017 7:04 pm

mrc wrote:
Wed Oct 18, 2017 4:51 pm
BW1985 wrote:
Wed Oct 18, 2017 4:45 pm
Does this happen to poplar? We just painted and installed our risers so I hope not. :confused
Nope. This is an issue with SPF (softwood) knots.

Zinsser B-I-N stain blocker (shellac) works great for this.
Whew! Thanks
"Squirrels figured out how to save eons ago. They buried acorns. Some, they dug up, for food. Others, they let to sprout, in new oak trees. We could learn from squirrels." -john94549

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sergeant
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Re: Stains coming through white painted wood stair risers

Post by sergeant » Wed Oct 18, 2017 7:10 pm

jimmo wrote:
Wed Oct 18, 2017 5:40 pm
Thanks all! Sounds pretty unanimous that I need to get some decent oil based primer or shellac. Hopefully that takes care of it because every time I go up the stairs it bugs me. Wife claims she didn't even notice until I mentioned it.
If it didn't bother my wife it wouldn't have bothered me. :D The quality oil based primer will take care of it.
Lincoln 3 EOW!

iamlucky13
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Re: Stains coming through white painted wood stair risers

Post by iamlucky13 » Wed Oct 18, 2017 7:37 pm

I don't remember for sure, but I think you need extra surface prep to apply shellac or oil based products over latex products. Among other concerns, shellac and oil paints are much less flexible than latex. I recommend looking for more info on applying oil over latex before starting so you don't end up with adhesion problems or cracking.

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Sandtrap
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Re: Stains coming through white painted wood stair risers

Post by Sandtrap » Wed Oct 18, 2017 8:19 pm

iamlucky13 wrote:
Wed Oct 18, 2017 7:37 pm
I don't remember for sure, but I think you need extra surface prep to apply shellac or oil based products over latex products. Among other concerns, shellac and oil paints are much less flexible than latex. I recommend looking for more info on applying oil over latex before starting so you don't end up with adhesion problems or cracking.
The area can be sanded with 100 grit just to create adhesion but not to bring out the wood below. Also can be cleaned with TSP for a better bond.

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