Refinishing an old deck

[Bryan11]

A friend has a 20 year old deck made of green treated wood that's structurally fine but not looking good. They'd like me to see what I can do to make it look better. When I looked up some guides, I'm seeing many different options. What do you think of these approaches?

1. Rent a pressure washer and use 1000psi to 1500psi to clean the deck with water. Let it dry a few days and then apply a clear or colored deck stain/sealer.

2. Wet the deck and apply a deck cleaner. Let that sit per the instructions and then use a pressure washer to rinse it, let it dry a few days, and apply stain/sealer.

3. Per This Old House: Use a hand sprayer to apply a deck cleaner, then use a broom type brush to scrub and remove any dirt. Spray with a garden hose to rinse, let it dry a few days, then apply a deck stain/sealer

Instead of using a packaged deck stain/sealer, would it work as well to use a mix of 50% mineral spirits and 50% linseed oil? I used that on a wood trailer last fall and it worked well.

Any recommendations for deck cleaners, or are they generally needed?

thanks,
Bryan

[Woodenfish]

Go with #3. Always use a deck cleaner before finishing/refinishing a deck. Even a brand new wood deck needs this important step completed. A pressure washer is a liquid wood saw. Never use one on a deck, wood or composite or risk severe damage.

[Willyou]

What woodenfish said. #3.

After that, consider a good stain/sealer. I've tried several name brands sold locally with very poor results. I finally ordered some TWP. After two winters (very mild where I am) the TWP has held up twice as long as the other stuff and still looks good. I predict it will last another 2-3 years.

Check this out.

I've also use several deck cleaners and I didn't find one significantly better than another. They all take a good deal of scrubbing with a stiff brush to do the job.

[tomsteve]

sodium percarbonate to clean then oxacyllic acid to neutralize.

dont use anything with bleach. bleach soaks into the wood. it dries out. water reactivates it.
bleach destroys wood fibers.

[Kansas City Fireslayer]

Spray on deck cleaner, let it sit and soak a bit, scrub it with a coarse nylon brush or similar and then carefully power wash all of it off. IME, a 2750 psi pressure washer was about perfect for a nice cleaning without tearing up the wood. Of course a little less or a little more psi would still work. There's a very noticeable difference using a deck cleaner compared to just power washing. I've done it both ways and the grain and stain color both come out better.

[sleepy hollow]

I found Sikken stains to be pretty good. I have tried others and they do not last. I suggest using a non-transparent type if that works with the decorating scheme. Has more of the pigments and other useful chemicals in it. Also I used a light colored taupe. My deck is on south side of house and the lighter color keeps it a bit cooler.

[DustyDan]

Don't use the pressure washer. It will scour out the softer parts of the wood and you'll end up sanding the whole thing anyway. Don't ask me how I know

[Cub_Cadet_GT]

I have always used a power washer to clean my decks. If you use the right tip and know what you are doing you will not harm the wood. It gets it MUCH cleaner than a garden hose and brush.

I always soak with a cleaner then power wash it. You didn't mention if it has an existing finish on it. If so is it transparent, semi-solid or solid?

[Bryan11]

Thanks to everyone for their help with this. Both my friend's deck and my own have been refinished and they ended up better than expected. Here's the process I ended up following.

1. The deck was cleaned with a 2000psi electric pressure washer. It had a spiral tip that spread the water so it didn't easily hit a single spot and damage the wood.
2. A two gallon sprayer was filled with a cup of Oxiclean and warm water. This was sprayed on the deck and it was rinsed off with the pressure washer after it sat for ten minutes. This part made the wood grain show up significantly more than before.
3. The deck was left to dry in sunny weather for a week
4. The two gallon sprayer was filled with a mixture of 60% boiled linseed oil and 40% mineral spirits. This was sprayed on all exposed deck surfaces twice.

[JimReed@Tallahassee]

Back in the day I moved into a house with a neglected 15 yo deck. That summer, I convinced my very young daughters and my new wife that deck work would be a good bonding experience for all. We worked on the large deck all week during their summer visit. I used a back saw to remove pine needles from between decking planks. They used scrapers to remove paint and then spackled the cracks on each board. It was hot, nasty work and has gone down in family lore as a task never to be revisited. I repainted the deck and it held up well for ten years. Then some housepainters offered to pressure wash and paint it for free as they did the exterior of the house. Sounded good to me.

But the pressure washing scrubbed out the old spackle and cracked boards took on water. Two years later and the decking was punky all over and needed replacing. Lesson learned--no pressure washing on decking.