[Cwhaine]

Just painted last year......then I see this happening..first thought it was mildew but tried cleaning with bleach but stain wouldn't go away

 

[huesmann]

Rough surface?

 

[Cwhaine]

No was painted b4..then reprimed and repainted

 

[mark sr]

What strength bleach did you use? try scrubbing?

 

[SW Dweller]

Did you use enough paint? Did you dilute the paint? How many coats did you install?
Was the paint frozen before use? Did you mix the paint enough before use?

Looks to me like there was not enough paint solids on the wall. I can attest that T-111 DRINKS paint. Looks a lot like T-111 rough sawn sheeting.

 

[robot123.nick]

Its the colorant in the paint washing out. You used cheap paint.

 

[RTFD]

Not a painting expert by any means but ....

I painted my daughters room a very similar shade of yellow. 24 hours later it looked like that.
It took 4 coats to finally get full coverage.
My guess is you just need another coat (possibly more) of yellow to get it to cover.

 

[SpentPenny]

Next time use a quality paint. that is just the result of cheap or diluted paint. garage sale find?

 

[Gymschu]

That’s mildew. Whatever cleaning you did before you painted did not kill the mildew spores. You painted over all of that and the mildew is growing again underneath the new paint film. Now you have one heckuva mess. I think the only thing you can try now is to saturate it with a mold killing chemical like concrobium and pressure wash the heck out of it and start over. But even that might not work.

 

[GCTony]

Yellow, the worst color to cover/hide anything. Seems like I'm seeing old mildew stains through the paint

 

[Moore3561]

I agree with Gymschu its definitely mold. I have had good luck doing a full prime with a quality exterior oil primer

 

[karoc524]

There is a mold prevention additive that can purchase next time to help prevent mold, but as others have said when it comes to exterior paint can't cut quality paint. I like the colors they both go good together.