Why Sanding a Deck Can be an Issue 4.7/5 (95)

This post was updated on October 21, 2024

Hi, I am Scott Paul. I have been prepping decks for over 30 years. My sanding deck help tips on staining decking are based on my history as a wood deck restoration contractor. See here for more info about me.

Why Sanding a Deck Can Be an Issue

I appreciate your input at Deckstainhelp.com as we continue to be your go-to source for the latest deck restoration news and trending topics through 2024. See below for an article about Why Sanding a Deck Can be an Issue.

Feel free to leave a comment or ask questions below.

Sanding A Wood Deck

Sanding A Wood Deck


Sanding your deck can reduce stain penetration

One of the most frustrating problems that can crop up when you stain or restain your deck is that the stain doesn’t absorb the wood correctly.

There are several different reasons this can happen, but one of the more common issues is that the boards were not correctly sanded or prepared for the task. Today, we will examine the main causes behind poor absorption and explore some of the measures you can take to negate this issue in the future.

Materials Need for Proper Deck Sanding

  • Dry weather and a dry deck
  • Gloves, protective eyewear, and sanding mask
  • Power Sanders: Drum, belt, and hand sanders
  • Sandpaper: 60-80 Grit

Drum Sanding DeckMy Deck Sanding Tips

  1. Never Use More than 60-80 grit sandpaper.
  2. Use a Power Sander
  3. Final Prep after Sanding
  4. Staining the Deck
  5. Confused? Ask Me for Help!

Check Your Sandpaper Grit

Often, we don’t invest much thought into the sanding process and get on with it without careful planning. This is where your difficulties will arise.

When sanding wood to prepare for a new coat of stain, you have to be extremely careful with how much you sand the wood and the level of sandpaper grit you use. Anything over 60/80 grit is too much and will leave the wood overly smooth. This means the pores are too small to absorb the stain correctly.

Use a Power Sander

My Pro Tip: Using power sanders will speed up the sanding process. Avoid circular sanders as they can leave swirl marks in your wood.

A good wood stain finish always starts with the correct sanding preparation. It is important to begin with a power sander and always finish by hand to reach difficult areas. Remember no more than 60 or 80-grit paper.

Final Prep After Sanding

My Pro Tip: Cleaning and Brightening after sanding will remove the sand dust and open up the wood pores, allowing the deck stain to penetrate better.

The next step is to clean the wood thoroughly after the sanding. Deck cleaners, also known as deck washes, lift dirt and unsightly mildew that accumulate over time.

Most deck cleaners contain soaps to help them clean effectively. The downside of the soap is that it raises the wood’s pH level. This can make the wood appear darker in color, and the higher pH balance also makes it more difficult for the stain to penetrate.

To reverse this after using a deck cleaner, apply a wood brightener. A wood brightener contains a mild acid formula that neutralizes the higher pH balance caused by caustic soaps. The effect is that the wood’s pH balance is restored, and the wood is brightened back to its natural color. This will ensure that your wood looks natural and shines through as it should after applying the stain.

Staining The Deck

My Pro Tip: In most cases, only one coat of stain should be applied to a sanded deck. The one exception is if a solid color decking stain is used.

All that’s left to do now is stain the wood. If you are having trouble with stain penetration, follow the steps we have outlined in this guide—oversanding does not have to be the end of the world. Sand the wood again, and make sure to properly clean and brighten it before reapplying your stain.

Need Help? Deck Sanding Questions?

Prep or Stain Help? Please ask me below if you have questions about my tips or need help choosing a stain. Just post a comment below and include as much information as possible.

Want more help on deck sanding? See How To Sand a Deck.

Please Rate This. You may also post comments or ask questions below.

author avatar
Scott Paul ~ Restoring Wood & Decks Since 1993 Owner
As an article and comment contributor to the site, Scott has been around the pressure washing industry since attending college. In 1993 he started his first company called Oakland Pressure Wash specializing in exterior pressure washing and deck staining. That company evolved into OPW L.L.C. shortly thereafter concentrating more on exterior wood and deck restoration. Scott and his Deck Cleaning Michigan company have restored over 10,000 decks in the Metro Detroit area since the early years. He has become an authority in the deck restoration industry and has contributed to numerous wood restoration forums and informative sites. All the products he suggests through this site are sold through online sites and in retail stores, allowing the consumer to choose their own means of purchase. Scott’s eCommerce sites do sell many top brands he endorses and if you appreciate any of the help he has offered then feel free to purchase from one of them.

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Jen Morgan
Jen Morgan
1 month ago

S year old cedar deck that was built last summer in South Dakota (extreme temperatures and both snow/rain). Last winter was fairly mild and we did not allow snow to sit on the deck but the wood had weathered and had small speckles of mold. We got around to prepping the deck for stain a couple weeks ago and am now realizing we made multiple mistakes. We first pressure washed then sanded everything with 120-220 (based on incorrect advice from a local hardware store- first of many mistakes). We then used a deck cleaner, and although we thoroughly washed after, we didn’t do the deck brightener until hours later. The wood then looked white or bleached in areas with some white fuzzies. So we started sanding with 80-180 grit to get rid of the white. Now after reading your sanding post, I believe we cannot stain as the pores are closed due to the finer grit, correct? What should we do about the white/bleached portions that are not fuzzy- Will it take up stain or do we need to sand it down to the raw wood as we had started to? The handrail is down to raw wood. It is mid September and I am worried about leaving it all winter again. It likely will not be nice enough to stain until at least May if we have to wait.

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Isobel
Isobel
2 months ago

Hello, We have removed all the old peeling and stuck on paint/stain/goop…then I cleaned and scrubbed with OxiClean, rinsed many times over, in the rain. When the rain stopped, it was dark so I did the oxalic acid the following day. I treated and rinsed many times over, waiting for the deck to dry now, BUT….the wood has quite a lot of furry bits that were not there when I began cleaning. What do I do now???? Please help

Sharon B
Sharon B
5 months ago

Company power washed unstained Ipe deck with just water ( I think) 10 days ago. The deck went from oxidized grey to blotchy white. They are waiting for dry weather to stain it with a natural colored oil. I took some 80grit sandpaper to some boards and took off the white blotches. Looks so much better. If they don’t sand will the blotchiness go away with the oil or do I need to sand it all off first?
If I need to sand, do I have to clean and brighten?
Oil? Are they any good? What do you recommend for Ipe
Ipe deck, 24yo, facing NE, 800sf still in great condition
Wooded Northern VA, half day blazing sun in summer, gets black slippery dirt when wet
Picture is after power washing. Company suggested Palm sanding with 120grit.
Thank you! in advance.
SB

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Sharon
Sharon
5 months ago

Well, the company came back after 4 weeks (it’s been raining every other day) to sand (he said it was 80grit) and put the oil (Messer’s oil and Ipe Oil) on the deck and it started raining when he was almost finished. The beautiful IPE deck looks like a zebra. I think it was not sanded enough. He wants to put more oil on it.

I’m sick. More oil? leave it alone until next year? Now what do now to remedy my Ipe situation? Thanks Paul.
SharonB

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Eric H.
Eric H.
1 year ago

Thank you for the great guide, I have a deck that is in North Dakota (So heavy snow and well below freezing temps in the winter) The deck gets full sunlight most of the day and it was built with pressure treated pine. The last time it was stained was with Tompson Semi transparent (that’s the only information I have on the product) about 4 years ago, so the stain is just gone in most parts of the deck.

I have pressure washed the deck, and used ZEP deck wash in a weed sprayer bottle and a heavy bristled brush, and that worked to get the mildew and and most of the old stain off, but there is still old stain left and the washed wood didn’t come out as an even color, so I am going to bite the bullet and sand the deck with a drum sander at 40 grit since we are going to use a Semi-transparent stain I don’t want to run the risk of the pressure washer ‘marks’ coming trough.

Once I am done sanding should I do the deck wash again or can I just move to the brighten step?

Renef
Renef
1 year ago

Semi-solid or solid for cedar deck in the Pacific Northwest?

Four yrs ago our redwood deck was restained with an inferior product that was supposed to be semi-transparent, but went on like solid. The color is an awful red. It hasn’t peeled but just looks blah. We are planning to restain/paint the deck now (along with the pergola)
I have decided to go with a semi-solid or solid to make it easier (I think!). What kind of product and prep do you recommend?

In which state is your deck located? WA state, Seattle area
How much sun/shade does your deck get? South-facing but on a greenbelt so sun in the summer
What type of wood is your deck made of? Redwood
Do you have mold or mildew issues? Very little on the underside of a couple of horizontal board of the pergola
Why/how did the previous stain fail? It has worn although, not peeled. It looks like orange paint.
What type and brand (if known) of stain did you use last time? HD Baer (contractor choice)

First photo (wet deck) is from 2021, the other two photos are recent

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Jason
Jason
1 year ago

I had someone clean our new PT deck 5 days ago, then they came out and got paint splatter all over (long story). I decided to finish the job myself to avoid a long drawn out situation. I went out today to start trying to get the paint off and noticed the deck already looking discolored and see a lot of wood fibers coming off the boards. Pictures are of the deck as it looks now, and one section where I sanded to get the paint off.

Do I need to start all over by sanding, cleaning, and brightening the deck before I stain? It’s been weathered a year already (another long story). I appreciate any advice you may have. This deck project has been a total nightmare from the beginning.

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Jason
Jason
1 year ago

Thank you so much for the reply! Do you think I should wash and brighten again or will sanding be enough?

Jason
Jason
1 year ago

Thank you! I might end up purchasing a new belt sander for this because of the large area. It would take FOREVER with my orbital sander.

John
John
1 year ago

I had a 50′ x 8′ treated lumber covered deck built three months ago. Can I sand off the mill stamps and then lightly sand the entire deck. Will this even out the light spots and allow me to not have to wait 2 or 3 months for it to weather before staining?

Ben
Ben
1 year ago

I have a deck ~20 yrs old, cedar. we bought the house about six years ago. They had about six coats of paint which was flaking off. About two years ago I sanded and repainted. It is bubbling now. I’m thinking about just resending and repainting. Thoughts?

Michael
Michael
1 year ago

20 years ago we put Thompson Water Seal on our PT deck… for the last 8 years we’ve tried to recoat to improve appearance. NOTHING will stick to it or penetrate, everything just flakes off. Do we need to replace the deck boards.

Michael
Michael
1 year ago

Thanks for the quick reply. No stripper tried (yet). We did a thorough pressure wash, let it dry for 3 weeks in the sun, and applied a BM Armorcoat porch paint. Rep claimed it would stick to anything, last for years, and we believed him, it went on like thick glue, looked great all summer and fall and then It peeled off in huge sheets after the first winter. Now the Rep claims Thompson Water Seal is basically paraffin and nothing will stick to it. Hopefully, a good stripper will get deep enough to remove that old stuff?

Dave Jensen
Dave Jensen
1 year ago
Reply to  Michael

There is a high tech test for seeing if your deck is ready to accept stain or paint: sprinkle a little water on it and watch what happens to that water. If it forms tight beads and those beads are still there after a couple minutes, NOTHING is going to penetrate into the grain. It will sit on the surface, look great this year, and FAIL the following spring .

L Hamm
L Hamm
1 year ago

We have just finished stripping and cleaning/brightening our 20 year old Cedar deck. It is in very good condition, with the exception of some the stair boards and a few spindles on the stair railing that were rotting, (they are exposed, and rest of the deck is covered). We have used Sherwin Williams SuperDeck semi-transparent originally and had recoated 4 times, and the last time it had started to peel off (down to bare wood in some spots.) It was more like a paint than semi-transparent. Want more of a stain look to allow woodgrain to show through. Not sure what product to use, we have a short window of temperatures staying above 40’s and not wanting to leave the whole deck unprotected over winter?

Fo Sf
Fo Sf
1 year ago

I have a fairly old redwood deck and fences. Because stripper (followed by brightener) didn’t remove all the old (film-forming) stain, I’ve had to sand some areas to remove that. While in a moderate climate zone, we’ve had recent rain and more is expected over the next 2 weeks. This has delayed the remaining sanding and the staining. How many weeks can the unstained redwood be exposed to the elements before it adversely affects the wood (both aesthetically and structurally)? And any suggestions for protecting the exposed wood until I can complete the sanding and stain it? While the deck is small enough to tarp, there’s too much fencing to do that. FYI, the deck is smooth surface and the fences are rough cut. Thanks very much for your advice.

Fo Sf
Fo Sf
1 year ago

Thanks for the reply. We’ve previously used RAD and this year used Woodrich HD-80 (both followed by brighteners). They left quite a bit of fur that required much sanding, a tremendous amount of work. Are there any gentler products that would still be effective yet wouldn’t cause furing? For same reason, we’d prefer to go with garden hose rather than power washer. We’d also prefer a gentler product to avoid further inconveniencing our neighbors. For protection, they’ve already had to relocate their patio furniture and wet their plants twice. (The contractor originally rinsed THE HD-80 off too soon and thus had to repeat the process.) Thanks!

Amy D.
Amy D.
2 years ago

Trying to redo a 10 year old deck. Some splitting, black and green. Had nothing on it existing. Power washed it clean. But transparent stains are turning out very very dark in color. I’m assuming this is because the wood is so dry and soaking up alot? Even the lightest stains are just so dark. Is there something I can apply to the wood so the stain won’t be so dark? Can I mix a clear with a transparent stain to lighten it up? Does this have anything to do with the fact it was only power washed? Any suggestions for stain?

Last edited 2 years ago by Amy D.
Dave Jensen
Dave Jensen
1 year ago
Reply to  Amy D.

Try diluting the stain with that brand’s clear oil.

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