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I have a deck that is old and falling apart so it is time to replace it. To replace the deck boards I plan to remove existing, measure boards, cut new board and put the same size and board back into place. The deck hasn't been replaced in twenty years and it currently has nails. Many tutorials and research show using screws. After a search under the tag I didnt see any questions on why screws would be better then nails other than I would imagine over times nails could back out. So why are screws better for deck boards then nails? Is there a particular screw other than a normal wood screw that would be good for decks?

  • Zach has it right. For the decking, use screws. For the structure, use nails and lags. They make "deck screws" now, that are designed specifically for decking. They're coated to prevent corrosion, and are available with Torx drive heads (which is better than Phillips, though not as good as Robertson). – Tester101 Jun 7 '15 at 3:27
  • @tester101 what is Robertson? – DᴀʀᴛʜVᴀᴅᴇʀ Jun 7 '15 at 4:36
  • @Darth_Vader: square screw drive. – Martin Argerami Jun 7 '15 at 5:41
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Screws hold better over time, so are preferable. Use a long (3") exterior grade screw and you'll be fine. I'd avoid stainless as they're expensive and sometimes brittle.

If the underlying joists are in rotten shape, come back and ask about them.

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Not the best answer, but:

Use screws on the top boards where people will be walking barefoot. Every kid has had a wicked gash from nails (naturally) poking up a bit.

Use big a** nails to attach your cross beams to your main structure. Nails are only good at holding against a shear, i.e. nails should always be (and only be) parallel with the ground.

Use large lag screws to hold together your 4x4(?) frame, the main, big parts.

Your deck will experience changes in temperature and the wood and fasteners will not adjust at the same rate. You want some give in a deck because of this. You also want some give because of the sporadic forces that humans will put on it. Nails provide some give. Screws provide absolutely no give; they will destroy the wood around before they back out.

Putting screws on the "floor boards" will wear out the boards faster, but in my opinion that is the sacrifice to prevent injuring the fragile humans.

Please also see this question. Those people are much smarter and concise than me.

  • I intentionally did not make any mention of the type / coating for these fasteners because @Craig has done a fabulous job explaining that. – Zach Mierzejewski Jun 7 '15 at 3:18
  • Good point about the inflexibility of the screws. And very good point about the nail heads poking up and stubbing toes. My big toe is cringing right now from the memory. But how often do screws really damage the decking? And over what kind of time span? Even if they pull partway through, you can drill a new one next to the old one (pretty? Not necessarily, but what deck is still pretty after 15 years no matter how you build it? :-) – Craig Jun 7 '15 at 21:31
  • This is a good answer. Also two other things. You screw your floor boards so they can be replaced easy. Also it takes like an extra 5 seconds per screw to hit it with a countersink at 1/4" before your screw. It will look better, be smoother, and you will probably save that 5 seconds back when screwing - unless you just like screwing longer :) – DMoore May 16 '16 at 19:49
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Agreed, use screws. Nails will pull out, and the shrink/swell cycle as the wood dries then gets wet then dries again can work the nails out of the holes, and make the holes slightly looser. Screws can't be pushed back out. They'd have to be twisted out, and the lengthwise force on the flat helical edge of the thread from tightening the screw down will remain for a very long time.

However; this probably goes without saying, but use the right screws, and the right hangers and other hardware.

Since chromated copper arsenate (CCA) has gone out of favor for pressure-treating lumber, the replacement chemical cocktails are more chemically reactive with zinc and can cause faster corrosion (destruction in years instead of decades). Your screws aren't going to hold if they've rotted into flaky rust all the way through, and if your joist hangers rot away your deck will collapse.

Some (most?) manufacturers of hot-dip (zinc) galvanized steel parts generally won't warranty how long their products will last in contact with pressure treated lumber. The zinc is sacrificial, so it gets corroded instead of the underlying steel. But the copper in the pressure-treating chemical brew will corrode the zinc forever, then the steel underneath will rust away. Still, even if the product has a lifetime warranty and you can get service despite using the parts with pressure treated wood, it probably means the manufacturer will replace the parts. They won't rebuild your collapsed deck. You'll have to do that yourself.

Galvanized parts are probably fine if you're using natural cedar or redwood because there aren't added chemicals that will attack the zinc coating.

The newer thing in coated parts is polymer (plastic) coated hangers and screws, or zinc-and-polymer coated parts.

Stainless steel is probably best for corrosion resistance, but expensive.

Good luck!

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The issue with decks is that they are outdoors, which means they will tend to expand and contract a lot with moisture and temperature changes. This will cause nails to come loose.

The best thing to use is a bolt and washer design, because it can be made to flex naturally.

Since it would be time-consuming and costly to bolt down every single board on the surface of the deck, the cost-effective alternative is a screw system system of some kind on the deck, using counter-sunk bolts only for the structure.

You should use a stainless steel, silicon bronze or brass screw system like Tiger Claw. Modern lumber is ACQ treated which will rapidly degrade any galvanized fastener.

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I was taught to use screws, preferably square drive, if not a star head is my next choice, theres also a special deck bar to help get those deck board where u want them. Ripping them old nails will be the hard part after that its cut and screw and ur good

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