Building a deck might not look all that tough on the surface. A couple of boards for framing, some deck boards on top, maybe a railing and definitely some stairs – right? Wrong.
The choice of materials you use to build your deck is a huge piece of the puzzle. 2 x 8 boards might work well for the framing, but as actual deck boards – the boards on top of the frame, the boards you walk on – they are not just overkill but can actually create an unsafe situation.
Below we go over when you can safely use 2 x 8s on the deck, where you should use other materials instead, and why sticking them in the right spots are so important.
Let’s jump right in!
Can I Use 2 x 8 For Deck Boards?
2 x 8 boards – pressure treated, of course – will work just fine in a lot of deck framing applications.
In fact, these 2x6s might even be a little overkill.
A lot of deck frames actually call for 2×6 pressure treated materials to be used, depending on the length of the spans required. 2 x 8 is the next step up and for longer runs with clear spans a little beefier material is necessary.
The trouble with using 2 x 8 material as deck boards, though, comes from the extra width.
You’d think that would be nice to get an extra 2 inches of coverage, cutting down on the amount of boards you had to buy while still covering the same area. Right?
Wrong!
Because the boards are going to be laying down on their flat surface, and because there is so much extra surface area on a 2 x 8 compared to a 2 x 6, you are going to be inviting a world of problems.
For one thing, these wider boards are going to be a lot more prone to sagging in between your joists. This happens with longer spans for sure, but it’s still going to be a problem even with relatively “cluttered” framing.
Secondly – and maybe most importantly – these boards are going to collect and accumulate water (as well as snow if that happens in your area) a whole lot more than 2 x 6 materials ever would. That extra water accumulation will lead to cupping and warping sooner rather than later.
That’s a fast track for a deck surface that gets really “lumpy” parent
Avoid using 2 x 8 material for deck boards and you’ll have a whole lot less to worry about.
Where Should 2 x 8 Boards Be Used on a Deck?
You can comfortably use 2 x 8 materials on their side to add a little more structural integrity to different joists, different headers, and (sometimes) even as stringers for a couple of steps.
Again, generally anything that a 2 x 8 can do for an outdoor deck – particularly smaller outdoor decks – a cheaper 2 x 6 can do just as well. Whether or not that extra peace of mind is worth the premium price tag is entirely up to you.
Sometimes, though, plans for decks will require 2 x 8 materials to be used in specific applications.
Anytime you have especially long runs and spans that aren’t supported by posts you’re probably going to want to go with 2 x 8 boards instead of 2 x 6 boards. But that’s something that a deck designer structural engineer will have to help you out with.
Better Deck Board Options
When it comes to finishing off your deck and putting down that final surface, avoid 2 x 8 materials and instead go with 2 x 6 materials, 5/4 boards, or composite materials that can be a whole lot thinner while maintaining their strength and durability.
The overwhelming majority of decks made with pressure-treated materials in the United States today are going to feature 2 x 6 planks that have been laid flat across 2 x 6 or 2 x 8 joists.
Some people, though, love to use 5/4 boards that they are going to stain and seal on their own for a more custom finish.
5/4 cedar boards aren’t all that uncommon, either. These can get a little pricey (especially these days) but cedar has a natural resistance to water, rot, mold and mildew, as well as pests and insects that often make the premium price worthwhile.
Finally, you have a ton of different composite material options to pick and choose from these days.
Engineered wood products are becoming more and more popular. They are also becoming a whole lot more affordable than they ever used to be in the past. Their long-term durability hasn’t been fully confirmed just yet, though.
Synthetics are always a popular deck board option and for good reason.
Available in an almost unlimited amount of colors, these deck boards are going to last a lifetime and then some. Often lasting longer than the deck frames that they have been installed on top of, even!
You do have to be a little bit careful with the way you cut and the way you fasten composite materials down to your deck. But as long as you do a little bit of research you really can’t go wrong with these options today.
They beat using 2 x 8 pressure-treated materials, that’s for sure.
Closing Thoughts
Can you use 2 x 8 pressure-treated materials for deck boards?
Sure. You could get away with it if you absolutely had to. If you had no other material on hand to use.
But there are just so many other better options available that you’d want to carefully consider those choices before deciding to go with 2 x 8s.
2x6s, 5/4 boards – cedar or not – and the myriad of composite deck board options out there are only about a million times better for the surface of your deck than 2 x 8 boards would be.
Best of all, these deck boards likely won’t cost as much as 2 x 8 material would (or they’ll at least be in the same ballpark).
Skip the big pieces of pressure-treated lumber when it’s time to finish off the surface of your deck. You’ll be glad you did!
