You loved your pressure treated (PT) wooden deck when it was new and looked like this:

And the PT decking had that beautiful, light amber stain.

But you have not treated it for years and now it looks like this:

Or this:

Or even this:

What should you do?  Can you restore it?  And is it worth all that work?  Before you power wash your PT deck or re-treat it, examine it closely.  You may have other, more serious issues to contend with.

These issues fall into 3 categories:

1. Underlying structure: Is the framing underneath sound, and is your deck properly built?  Is it safe?  There’s no sense in spending six or ten hours or hundreds of dollars to beautify your deck if it may injure you or it may collapse.  You can determine quite a lot about your deck by examining it yourself – for guidance see my blog post about Deck Safety.  If you are unsure about its framing or suspect your deck may not be safe, get a professional inspection.  (For clients in northeastern Massachusetts, we offer a Deck Safety Inspection for a minimal charge.) Avoid a bad surprise:

2. Minor Problems: What are the floor boards like?  Are they flat and solidly fastened?  Or has the wood cupped or split?  Are there loose and protruding nails or sharp splinters that will catch bare feet?  Do the rails shake?  Do your stairs scare your guests?  These problems are usually fixable – by you or by a professional.

3. Appearance: If you’ve read this far, your deck has probably faded and may be stained with grease from a grill or have black mold stains.  Power washing and re-treating it can dramatically improve your deck’s appearance. But a  painted deck presents a greater challenge.

Overall, there are three alternatives for your deck:  Restore it, renovate it, or replace it entirely.


If the deck’s structure really is sound, you can choose to fix minor issues and then restore much of its original glory.

  • Among the minor issues, loose nails are easy.  They loosen when wood shrinks and swells with moisture changes or when the nails rust and become thinner.  Don’t waste your time pounding a loose nail back down.  The nail is loose because its hole is larger than the diameter of the nail.  Pounding it back down may seem good now, but Mother Nature is devious and persistent.  Pounding the nail down widens the hole more, and whatever force loosened the nail originally will return.  You must do just the opposite:  pull out the nail and discard it.  The solution here is a screw:  a hot-dipped galvanized screw, stainless steel screw or a coated screw guaranteed not to rust.  The screw’s shaft diameter must be as large as the nail hole and its threads must be larger.  I’m talking here about a 2 ½” long #9 or #10 screw, depending on the size of the original nail.  Use a power drill and watch the wondrous results:  as the screw tightens, it will suck the board flat.  If you use an impact driver, be careful;  they are so powerful you may just drive the screw through the deck board.
  • Cupped boards are more difficult.  If the cup is small and the raised edges are not too high, you can sand it down and use screws to further pull it flat — or you could just live with the small cup.  But floorboard edges that are raised high could trip someone.  Such seriously

    Clamp & screw down?

    cupped boards require serious tactics.  If you can clamp the raised edges down (as on a rail cap), do so, and then screw it flat.  Otherwise, consider flipping the board over.  The cup will now slope down, and the drying forces that previously cupped the board should now work to straighten your board.  The new top side may show significant discoloration that you’ll want to sand or perhaps power wash.  It may be easier here to just replace the offensive board.

  • Splits in boards are problematic.  I do not recommend

    Click to enlarge

    filling splits with putty or wood fillers.  Despite manufacturers’ enticing claims, even “external wood fillers” will not endure outside with swings of 80% in humidity and 90 degrees in temperature.  Remember that “devious and persistent Mother Nature”?  Replace seriously cracked boards.  A note about splits vs. checks:  Splits extend all the way through a board and weaken it.  Checks extend only partially through the wood (1/3 or so).  In PT wood, checks are the normal result of the natural drying process.  They are most prevalent in larger dimension wood (4×4 rail posts, 6×6 support columns).  Despite their size, checks do not weaken the wood.

  • You can sand small splinters.  For larger splinters at the side of a board, cut out the splinter with a knife at an angle and then sand it smooth.  The board will be imperfect, but will no longer be dangerous.
  • Old, flaking paint can pose a real problem, especially if the paint is thick.   For example, cleaning a deck floor like this thoroughly enough for it to look good will take a tedious combination of scraping, chemical stripping, power washing, and sanding.  And even then, the results may not prove satisfactory.  Better to skip all that work and replace the flooring.
  • If your deck surface is more benign — faded, mottled-looking with worn stain and minor roughness — you may want to sand your entire deck.  Unfortunately, you should not sand only part of your deck.  Sanding exposes lighter wood just below the surface and, if not done completely, will leave unsightly light and dark areas.  So you’re stuck sanding the entire surface.  This can be a daunting task if your deck is large.  If you have limited experience with a sanding machine, I recommend using a random orbital sander.  Its slower speed offers greater control, and its random action eliminates noticeable scratch marks when you sand across the grain.  To the contrary, a belt sander is much faster, but its greater power can do more damage.  You must sand parallel to the grain, and if you are not very careful, you can gouge the wood deeply.  With either sander, the most critical step occurs before you pick up the sander.  All nails and screws must be counter-sunk below the surface – otherwise the protruding steel will tear up the machine’s sandpaper or even the machine itself.

Tired yet?  Take a break before you tackle the next step.

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So, your deck is structurally sound, and you’ve fixed those troublesome boards and replaced all the loose nails with screws.  Your deck has weathered and discolored badly, has some grease stains from the grill and accumulated dirt.  Now it is time to clean off the deck floor and brighten the faded wood.  Chemical cleaners, a stiff brush, and your elbow grease can be effective.  But I’d recommend an alternative that uses plain water instead of harsh chemicals and that trades off scrubbing on your hands and knees for a careful use of a power washing machine from a standing position.  (OK, I admit my choice here is influenced by the age of my knees.)  You can rent a power washer for fairly short money or buy one for a few hundred dollars.  Proper technique is important however, and I’ve explained the process in detail in another blog post.  See step 7 in Eight Tips for Maintaining Your Mahogany Deck. The correct process is the same for pressure treated wood as for mahogany.  The results can be dramatic:

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Your deck is now fixed, cleaned and ready for a preservative.  Happily, the worst part of your task is over.  Treating your pressure treated deck is not difficult;  but again, technique is important.  First, select a good wood preservative.  I recommend one that includes a semi-transparent stain and is formulated for PT wood.  Do not use paint on your deck floor.  Let me re-phrase that, lest you misunderstand.  NEVER apply paint to an exterior deck floor. Paint is a film that will peel, chip, and flake off.  Remember that painted deck from above?

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Like it?  Want it to be your deck in a few years?

Use a preservative stain — it will soak into the wood and will not flake.  I recommend using a semi-transparent rather than solid colored preservative stain.  Sure, solid stains come in a wider range of colors, but foot traffic on a deck floor will wear the solid colors unevenly and require more frequent (and complicated) maintenance.  Semi-transparent preservatives show the natural wood grain and age more gracefully.  The best preservative stain for PT decks that I’ve found over the years is TWP, which stands for “total wood protection”.  Use series 200 for PT wood.  It is available on the internet in 8 colors, although the “clear” version lacks pigments and thus will allow your deck to fade much faster.  I’d also suggest you avoid the “California Cedar” color, as it can leave uneven blotches on pressure treated pine.

Applying the preservative to your deck requires only a little technique:  see step 8 of that same blog post about maintaining mahogany.  Your deck must be totally dry before you treat it.


If your deck is structurally sound but all the repairs I’ve described seem like too much work, or if treating your deck every year seems like too much work, consider renovating it.  Remove the wood flooring and rails and install new, low maintenance materials.  Keep the frame.  The selection of PVC decking and rails available today is excellent.  The best products look very natural and are stain resistant, scratch resistant, and mildew resistant;  some even offer fade resistant guarantees.  Compare these samples — which one is synthetic?



I cheated:  only the last one is wood.  The first three are synthetic.

This beauty and low maintenance advantage comes at a price, however. The new synthetic decking and rail materials can be three times the cost of PT.  But you are re-using your existing deck frame, and the labor to install low maintenance materials is the same as installing high maintenance wood.  More importantly: what’s the value of your labor to repair and re-treat your wood deck every year?

For guidance on how long different decking materials last, see my article about deck longevity.


If your deck has serious structural flaws or you want to change its size or shape, then you’ll have to build a new deck.  Here your choice is fairly clear:  low maintenance decking, rails and trim at a higher initial price or wood with higher long term maintenance.  I’ve written some informative posts that can help you choose:

Once you decide to replace your deck, you’re free to re-design it.  Think beyond the square box.  You can have angled corners, interesting shapes, and multi-levels.

To see more design ideas, visit our website.

When rebuilding your deck, be sure to choose a professional deck builder who will design what you need and build you a well-crafted, solid deck.  Don’t buy into another structural nightmare.

We at Advantage Design & Construction offer professional design and build services for clients west and north of Boston.  Over the past 27 years we have designed and built over 1,000 projects.  We have enhanced the depth of our expertise by limiting our work to decks, porches, and sunrooms.  To view some of these projects, visit our website. To learn how we treat our clients, check our ratings on Angie’s List or read a recent article about us in Remodeling Magazine. For a free design consultation and a relaxed and rewarding design and construction experience, contact us via e-mail, or by phone, 781-273-3500.

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