As we've remodeled the house, I've replaced some of the structure with more modern woods (ie: 2nd floor ceiling joists that were 2x4's are now 2x6's)

Because of this, I have an excessive amount of old 2x4 lumber in my garage. It's either have 1 hell of a bonfire in the back yard or try to reuse them.

So I'm curious - I'd like to take this wood and build a deck out of it.

I'd build a frame 16 inches on center; use concrete corner posts I've seen that have a + channel in the top of them for the corners and center supports. Grade the ground, remove the grass, put some 6mil plastic down and put my frame over it on these posts. I'd give all the wood a quick sanding, maybe a coat of stain and a few coats of poly to try to protect it from the weather. More 2x4's as the deck planks and secure with galvanized screws (as I prefer screws to nails).

I know the wood is not pressure treated - is this a problem for outdoors if i protect it with a few coats of poly?

the deck would only be < 12 inches off of the ground. Do I need > 2x4 for the framing? I could probably afford to do the framing in 2x6's.

  • 1
    If you're in the US, you'll likely require a permit to build a deck. Because of this, the deck will have to meet minimum code requirements and will be subject to inspection. 2x4 joists will almost certainly not pass inspection (though I don't have IRC in front of me, so I could be wrong).
    – Tester101
    Jun 18, 2012 at 16:52
  • It wouldn't be attached to the house; no steps, floating (i may even put it a few feet away from the house to landscape around it) - as if i screwed a frame together and put it on the grass, but i'm putting it on concrete blocks to keep it up off the grass to (try to) avoid moisture
    – lsiunsuex
    Jun 18, 2012 at 19:32
  • @Mario A floating deck with no steps? Odd... why do you want to do this? Jun 18, 2012 at 19:49
  • with chairs and a table, we don't particulary like sitting on the grass. hard to move chairs, etc... would be better than nothing until we can afford to do a proper patio. i can spend a couple $$$ on some 2x6's, etc... and re-use some lumber. I can't spend $$$$ on a proper patio right now.
    – lsiunsuex
    Jun 18, 2012 at 21:29

4 Answers 4


How old is the wood? If we're talking 70 years or so, definitely don't burn that stuff as that'd be old growth wood which you just can't get anymore (easily). I'd even have a hunch that a 70 year old 2x4 might carry as much of a load if not more than a modern cheap pine 2x6.

All that said, as you state, it's not treated lumber. Unless it is cedar, you likely won't get much life out of it as a decking material--unless you have plans to refinish it each and every year.

The 2x4 also wouldn't make for a sufficient floor joist, so you'd have to use new structural lumber for that anyways.

If it's old lumber, I'd consider saving it for another construction project, or donate it to your local re-use center or habitat for humanity. If it's not old lumber, I'd use it for the fire pit.

  • I'm going to assume its original to the house, and the house was built in 1920's so... an actual 2x4 - not dimensional.
    – lsiunsuex
    Jun 18, 2012 at 19:30
  • 3
    That's probably pretty nice, tight-grained wood, then.
    – DA01
    Jun 18, 2012 at 19:39
  • 2
    Before I had the floating patio idea, I thought to reuse the wood to make a nice solid desk - the wife thought it was weird to use 2x4's as a desk - i think its their glued together, planed and stained / poly'd nicely, the distressing of the wood from the years would look cool.
    – lsiunsuex
    Jun 19, 2012 at 15:05
  • I think that would be a fun project.
    – DA01
    Jun 19, 2012 at 16:23

There may be a 3rd option for your wood:

Many regions now have recycling centers dedicated to re-using old construction materials salvaged from rehabbed housing. The wood is too high quality to burn, but not really suitable for an outdoor use, even with treatment. Someone can probably use it in a way that will preserve it for another 90+ years. On google, search for:

"Green Demolition in [your nearest city]"

"Building material salvage [your nearest city]"

and whatever else you can think of. There are lots of places out there, now. Some may even pay you a token amount for recycling the wood.

  • or just put it craigslist if you can't find a utility use for it yourself. I'd love to buy some cheap dimensional lumber for all manner of utility uses around the house, barn, and workshop!
    – aaron
    Aug 13, 2014 at 14:02

Use the AWC span calculator, and you can figure out the maximum safe span for your old 2x4s. On a deck about 8 feet is max if I recall correctly: http://www.awc.org/calculators/span/calc/timbercalcstyle.asp

That said, local codes may override this. Many span tables start at 2x6. Don't burn such nice old wood!


Presuming you're not running afoul of local deck codes, I'd say it sounds like a nice deck. Go for it!

If it's able to remain mostly dry, and if it's NOT infested by termites, and especially if you use a quality finish to limit UV radiation damage, then it should outlast a treated deck by a decent margin.

(The only benefit that treated lumber has over this wood is termite/fungus resistance)

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