Usually mildew that bad needs to be power washed after applying the Jomax.

I can certainly try that. I do have free access to a 2400 psi Karcher. I just don't want to remove stain since I am not ready to pay someone to stain my house right now (I need to fix some trim work first).

In prepping for restaining, would you use a stronger solution than Jomax according to directions in addition to pressure washing, or do you think that will take care of it?

Would TSP work any better? I think TSP and strong bleach can create chalking, so I better be priming for topcoat soon after?

Thanks for the feedback.

Pete

Nah, Jomax is your best bet. Use a garden sprayer so you can really soak the area. Don't forget to either protect plants and vegetation or soak them first with water so the Jomax will be able to be rinsed away. For really stubborn mildew removal, I will just do more applications or more soaking before power washing. That kind of mildew is just really hard to remove without power washing. It should be fairly hard to remove the stain with the power washer, especially if you only have a 2400 psi one. You would have to hold the wand very close and go very slow. The trim is a different story though, depending on what kind of wood/coating was used there. Usually, it it easier to remove the paint from the trim with a power washer.

Was the P&L Accolade stain that was used oil based? That mildew looks pretty widespread. Choose an acrylic stain this time as oils tend to act as breeding grounds for mildew.

Thanks for the great tips!

I did use a sprayer and soaked some areas multiple times. I believe you are right on the money about the pressure washer.

I appreciate the specifics - I would have thought to keep it far away with the pressure washer. I guess I will use a tight angle nozzle, also, but still fan shaped. The stain does hold really well, unlike paint as you mention.

The trim is painted and cleans very easily - the mildew is gone before you even rinse and it looks bright white.

I will check, but I believe the painter used oil primer - to soak in or seal better (something like that), and I am pretty sure acrylic stain. I get a ton of sun where these pictures are taken and the stain started to break down after 3 years or so in these areas (noticeable fading and mildew).

Any recommendations for the next time around besides making sure it is acrylic? We love the yellow color but need top-notch mildew and fade resistance.

Thanks again,
Pete

You can experiment with the power washer. Start far away and then move closer. If you start to actually strip off the stain then you know where the limit is. You can also try different tips. You can add a mildewcide to the paint which should deter the growth some. You can also wash the house once a year to keep the mildew in check. For that you would want to use a house wash product though because Jomax is really for prep prior to painting.

The existing mildew doesn't have to be bleached white, just dead. A Jomax or bleach soak will kill it in 10 min. I agree with the mildewcide additives. I don't paint an exterior without it.

I always thought if you could still see it it wasn't dead...but maybe I am wrong about that.

The trim paint was Accolade, the stain was actually Pratt and Lambert Stain Shield (solid), both 100% acrylic.

Pete