Power washing and re-treating the deck?

[CANOPY SAM]

We have a beautiful wood deck around our house. There's a boardwalk from the front entry, wrapping around the house, wide staircase, etc. Total surface area of around 1200 sq feet.

On Friday I borrowed a good power washer thinking I'd knock this out in a couple hours. Wrong! I spent 13 hours slowly and carefully removing years of accumulated dirt, mildew, and filth. I had no idea it was this dirty till I started "peeling" off the layer of scum!

I'm now down to original wood, which is as clean as I believe I can get it. My questions are these...1)Is there something I should do to the now clean wood to prevent future mildew formation prior to putting on new stain and poly and 2) I finished washing on Saturday afternoon. How long should I wait for the wood to completely dry before re-applying stain and finish?

I'm extremely lucky that we've had two hot dry days since I completed the wash, and have another few days of hot dry weather in the forecast. I was thinking I'd start reapplying product on Tuesday afternoon. Is this too soon? What will happen if there is still moisture deep in the wood decking?

[BartmanMN]

From DIY. I'd wait 2-3 days after your power washing to dry out well. My deck was only a year old so power washing was enough. An older deck may need a cleaning agent like shown below. If you think it looks good enough, then you are fine. If you think you need something additional to clean mildew then get the cleaning agent.

Step 1: Choose a Cleaning Agent

Choose the right cleaning agent for the job. If you've kept up with regular maintenance, a basic deck wash will remove dirt, fungus, and traces of sealant. A heavy-duty deck cleanser will do all of that, plus eliminate spots and semitransparent stains. To battle heavy soils or remove waterproofing and opaque finishes, you'll need a deck stripper. Cedar and redwood boards require a brightener, which restores the natural wood tones as it cleans. Pour your solution into a plastic pump-action garden sprayer.

Step 2: Clean the Deck

Drench surrounding plants with water (and cover delicate foliage with plastic sheeting). Working in an 8510-foot area, spritz the cleaning formula onto the deck. Let it sit (following the manufacturer's instructions), scrub with a synthetic stiff-bristle brush, and rinse with the garden hose. Repeat on the rest of the deck.

[Whoaru99]

I had some mildew growth on some cedar siding that was down to bare wood in some spots. I used a product called JOMAX (in a one gallon jug) that I got at Menards, and mixed with bleach per the label instructions. Worked really good, IMO. Treated areas looked almost as good as new wood when I was done.

[K_Josh87]

spray it down with a 50/50 mix of clorox bleach water mix, rinse it off. Wait for a week or two of good dry weather, re stain... its cheap and effective. We do this with log homes and it works well. and yes, clorox name brand is important, not 100% sure why, but it works the best. good luck

[K_Josh87]

the bleach water mix should leave it looking "new" with a bit of a duller appearance than brand new lumber... but once stained it brightens back up.

[chanfish]

agree on the bleach/water wash and rinse.. wish i would have known that sooner..live and learn on these projects. the bleach really whitens up the wood..i use the same stain as was on the deck before so i dont worry about stripping the old stuff off..

[K_Josh87]

it brightens the wood, but it also kills the mold and mildew that causes the darkening... if you ever have a bit of mold growing in an area (say a bathroom ceiling) do the same exact thing with a spray bottle...and do it before it takes off on you and no long term issues should arise...

[beer batter]

When is this bleach treatment to be applied? Is that after the deck has been power sprayed, or is there no need to power spray the deck when using the bleach?

[K_Josh87]

if there is no previous stain left, or ever applied, i would try just the bleach mix, and rinse... if you pressure wash there is a tendency to have "fuzzies" left on the wood surface...

[K_Josh87]

check out you tube, search "cleaning logs" or something to that affect, and you will have some videos to check out...

[11-87]

A simple trick to use when ready to stain... put a cup of water on the deck, when it soaks in, it will take stain.

TSP is a good cleaner:

TSP is commonly used after cleaning with mineral spirits in order to remove hydrocarbon residues.[citation needed] TSP may be used with household chlorine bleach in the same solution without hazardous reactions.[4] This mixture is particularly good for removing mildew, but is ineffective at permanently removing mold.

[CANOPY SAM]

Wish I'd gotten the bleach tip prior to re-staining, but such is life. Thanks for all the great tips folks.

Here's a little heads up for ya'll if'n your planning to do this project.

As I was really looking bring out a warm, rich old wood look I asked the good people at the big box store what product might do this. I was told to try Thompson's Water Seal in a "Cedar Tone" color. The "swatch" of color on the can actually did look like the color I was hoping to achieve.

After staining one length of board I stepped back and looked closely at my work. Much to my dismay, what I was looking at was basically orange paint! Even after drying it still just looked like orange paint. This was not at all what I wanted, nor did it look anything like the color eluded to on the can! What a joke!

I returned to the store and explained my situation and the same people said, "Yea, that's what cedar looks like!" OMG! I politely explained that cedar wood grain looks nothing like orange paint. Obviously, when it comes to paints and stains, you really get what you pay for!

I settled on a Pittsburgh Paints Acryl based toner in Honey Gold. It's absolutely beautiful, and exactly what I'm looking for! It's taken significantly more product than I originally planned for, as this heat and super dry weather has caused an awful lot of product to soak into the very dry wood. But I imagine that's a good thing in the long run.

Wondering if I should add a coat of clear finish over the stain and sealent...just for a little extra protection for this beautiful new finish?

I'll post pics of the project when it's all wrapped up.