Goodbye Wood Deck Framing… Hello Steel Deck Framing


Chances are if you have a deck in your backyard–even if it’s a newer synthetic deck–the underlying support framing is pressure treated wood.

Pressure treated lumber is cheap, readily available and using it is a no brainer for the average contractor. “I’m going to build a deck, I’m going to use pressure treated wood” they automatically think to themselves. I’ve built hundreds of decks using pressure treated lumber, but I started getting increasingly frustrated by it.

The wood being harvested these days from forests is “new growth” wood for the most part. This means the trees are relatively young before they are cut down. There are barely growth rings on lumber we get these days (you know the number of rings a tree has is an indicator of its age, right?) and the more growth rings, the denser the board and the stronger and straighter it will be.


You can visibly see the growth rings in this tree however this is a young tree. The rings would be much denser in an older tree.

Older lumber was much denser than the lumber we get today and was generally of a higher quality. Trees can only grow so fast and demand is high, so we get what we can get at this point.

Aside from the wood being “young”, the pressure treating process has been changed significantly in the last 10 years and chemistry used in the treating process has been cleaned up to meet environmental concerns. The lumber mills will tell you the new processes are better than the old ones, but ask any carpenter and they’ll all agree the new lumber is terrible. Not a little worse…Absolutely terrible in comparison.

I got tired of dealing with the unpredictable characteristics of pressure treated lumber. Sometimes it comes soaking wet, sometimes it’s dry as a bone. Sometimes the boards shrink a little when they dry out. Sometimes they don’t shrink at all. Despite our best efforts to frame a precise pressure-treated frame, we simply cannot control what the wood will do as it seasons or dries out in it’s final position as part of deck.

Pressure Treated Framing Moves at will

Look at how the deck boards are ridging at the intersection (Click the photo to Zoom in). This is not sloppy craftsmanship but the result of three different underlying framing members shrinking and crowning different amounts. This was glass flat upon completion of the job, but the wood does what the wood wants to do!

This unpredictability means that a deck can develop dips and dives, and deck boards attached to the framing move out of plane creating raised and ugly joints. It’s frustrating to see a beautiful deck compromised by the irregularity of inconsistent framing lumber six months down the road.

In a quest to always provide the best product to my customers, I’ve completely abandoned pressure treated lumber in all of our new deck projects in lieu of light gauge steel framing (LGS). Just a few of the benefits of steel deck framing are:

  • Lighter in weight but stronger than wood
  • Wildly increased joist spans mean less beams and less footings. This is a really big deal on raised decks with patios underneath.
  • More design flexibility. If I need a longer span I can change the parameters of joist from gauge, flange width, and web depth. With wood, we are stuck with 2×8 through 2x12s.
  • Perfect material. Every joist is made by a machine so there are no inconsistences from joist to joist like wood. Sometimes two wood  2x10s can measure up to a half inch differently!
  • Perfectly flat, level and square decks. The consistency of the material means that everything is extremely precise.
  • No shrinking, warping, twisting or shape changing.
  • Very little waste. All the steel is delivered to the job site pre-cut so it just has to be assembled.
  • When completed, it’s nearly impossible to tell the framing is not wood.
Steel Deck Framing in New Jersey

This multi-level deck is looks different now, but look at the photo below to see it when it’s finished and  it looks no different from what you’d expect.

Steel Deck framing provides a glass smooth deck surface

This deck surface is not just flat. It’s perfectly flat and will stay that way forever unlike wood which wouldn’t start or stay this flat.

This is a steel framed deck. Can you tell?



More and more leading deck builders across the country are abandoning wood in favor of steel framing because there are very few downsides to using steel. The main roadblocks to getting started with steel for most contractors are:
  • Lack of knowledge or understanding of steel framing methods, materials and techniques
  • Resistance to change because they are comfortable in their old ways
  • Cost. Most think it’s more expensive than it is or too labor intensive. It can be more expensive and it can be more labor intensive in some circumstances but not all. Usually the minimal cost difference is well worth the value of the finished product.
  • It’s not locally available. Nonsense! Light Gauge Steel framing is available everywhere. If there’s a commercial building in your town, you can bet it’s got LGS in it.

This is a steel frame deck, too.


About Greg DiBernardo
Greg DiBernardo is the owner of Peachtree Decks and Porches in Alpharetta, GA and specializes in custom deck building, porch construction and complete backyard renovations. His expertise has been recognized by key manufacturers in the deck industry who call on him to develop, refine and evaluate new deck related products. He's a regular contributor to Professional Deck Builder, The Journal of Light Construction, and Tools of the Trade magazines. Greg has also been featured on television, most notably on the DIY Network.

34 Responses to Goodbye Wood Deck Framing… Hello Steel Deck Framing

  1. Kreg McMahon says:

    Great article and very informative thanks

  2. Greg. Nice piece. Tell me more about this deck in the last photo. What decking and fascia material am I looking at? Are the posts and beam PT? What did you wrap the posts with?
    Thanks in advance.

    • Hi Gary, the deck and fascia are both Fiberon Horizon Tropical Ipe. The girder is 10″ steel with Fiberon fascia applied to it. All vertical support posts are PT on helical piles. The main support posts are wrapped with Versatex wraps painted with vinyl safe paint.

  3. Stan Weiland says:

    Greg – good article! I understand that you can buy LGS framing anywhere but we have found it more difficult to obtain it in a galvanized finish so that there are no rust and corrosion issues. What type of LGS framing are you using and is that a concern to you?

    • Hi Stan,

      I’m actually in the process of writing a piece on light gauge steel framing for Professional Deck Builder magazine–most of your questions will be answered.

      That being said, you want to order the steel with G90 galvanization (which shouldn’t be hard to get). G90 is the galvanization standard most exterior steel is treated to. The only reason Zmax or Triple Zinc hardware came into existence was to provide a higher galvanization for use with direct contact with ACQ lumber–Not because G90 was inadequate.

      I would not use G90 LGS framing on a coastal project with salt spray.

      Hope this helps!

      • Michael says:

        Hi Greg,
        Would you have any idea of where I could find light gauge steel framing products (Other than Trex Elevations) in the Denver CO area? I have been searching the local steel suppliers without any luck. Thanks for the help.

      • Michael,

        I believe CEMCO is a LGS manufacturer in your market. If all else fails, find a commercial drywall supplier and they will absolutely have access to it.

      • Michael says:

        Thanks Greg,
        I will contact Cemco to see if they have a distributor in the Denver area.

  4. Wayne Henderson says:

    Hi Everyone,

    Have you looked at the Trex Elevations Steel Deck Framing? It facilitates all the points discussed and is manufactured by Trex for your markets and it includes a great warranty. Check out

    • Hi Wayne,

      I have used Elevations in certain circumstances. The article I wrote that will be published in the winter issue of Professional Deck Builder magazine will explain the positives and negatives of Trex Elevations versus using generic light gauge steel framing materials.

      The main issue I have with using Trex Elevations is the lack of design versatility and the tremendous amount of additional labor required to use it versus generic light gauge steel framing for decks.

  5. WJB says:

    How do you attach the deck boards to the steel joists? Screws into the steel, either through the decking or with hidden fasteners will compromise the galvanization of the steel and allow rust to start at every hole. What is the material cost relative to wood?

    • We use hidden fasteners with self tapping screws. The galvanization is not compromised even when cut. It’s too complicated to explain here, but suffice to say it is not an issue.

      Steel is generally more expensive than wood, but not by that much relative to how superior it is. Put it to you this way, my company no longer even OFFERS wood frame decks.

  6. Hi Greg, Thanks for the article. I went to a local building supply warehouse that sells Cemco products and got a spec sheet. The strengths seem about a third greater than wood. I really like the idea of not having to fuss with the crowning problem. I want to get started using this for building decks. It seems that the 6″ joists could be used, at least strength wise, for smaller decks. Is there any reason to use something bigger, like a 8″ or 10″, if the 6″ strength is ok? Also, does the traditional wisdom for joist spacing still apply? It looks like the deck in your picture is using 8″ joist 12″ OC. Have you done any 16″ OC?

    • Hi John,

      You can use 6″ joists but it is harder to get fasteners installed because the web is too short to fit a tool in.

      We normally use 8″ or 10″ joists 16″ on center which is a factor of the deck board spans. You can also decrease the joist spacing to get a longer span just like wood.

  7. Thanks Greg, One other question. When needing longer beams, say 30′, have you found you can get those lengths? Or are you fabricating them? Alternating track and studs so the seams don’t meet?

    • We have gotten a couple of long beams in the past. Ask your supplier what they can get. You can break beams on top of posts and stagger the seams like you would with wood.

  8. Terry Howery says:

    Hi Greg,
    I have framed a 16 x 30 deck at my house with Cemco light gauge framing and I’m very pleased with the results. My question is in regards to handrail post attachment. My approved drawings, show an attachment similar to the Trex method (attaching to the inside of the rim joist with carriage bolts and then trapping the post on the other three sides with joist material) This is a time consuming process. Is there a faster and better way to attach handrail posts? I was considering the Titan surface post mount. Any suggestions?
    Thank you

  9. Kirk says:

    thanks for the info on this website. You mention using Invisifast system by MM Products when attaching timber onto LGS. I first was thinking of face screwing the timer into a timber base (and then plugging many holes) but now I’m very interested in using redwood timber with a LGS base with one of the Invisifast products. Not a contractor but a serious DIYer.

    So, when you use those Invisifast clips with timber on LGS, I’m curious how tight the final bond will be. The LGS is relatively thin wall and has one (or two) screw threads in contact with the metal. Based on that, I don’t see how you get a good bond with a sheet metal screw going thru the clip and into the LGS ? I’m pretty much sold on using LGS, but I have that underlying concern. Can you elaborate on that concern ? Would you ever face screw timber decking (then plug) into LGS or is that crazy talk ? I’m just an old school guy and think you gotta drive a screw far to get a good bond.

    • Kirk,

      It seems odd to me to put a wood deck on a LGS steel frame. You should reach out to Will at MM Products to see if he even makes a clip that would work with Redwood. We usually install grooved capped composite decking with the Invisifast system. Self tappers hold incredibly strong. No worries there.

      Starborne does make self tapping face screws you could use but that Redwood is going rot quickly on the face where the screwheads will create dimples in the face.

      • Kirk says:

        Ok, thanks for the reply. Can you further explain why it would be odd to put redwood on an LGS base? Is it because of the rotting problem you mentioned? I like the natural wood look. But, what synthetic decking do you recommend that looks most natural ?

      • Kirk,

        You are free to do whatever you want, but redwood is not that durable so you’d be putting a somewhat disposable and imperfect product over a very durable and perfect substructure.

        Laying wood decking is imperfect and irregular. One of the main benefits of LGS framing is that it’s perfect. I don’t think you would notice a difference with wood on it.

  10. Robert Bloodworth says:

    How do I find a dealer of LGS in my area, internet searches are not great, I am in So Calif

  11. Darren Finn says:

    Thanks for your timely recent reply. I am looking at doing a large deck with versa deck dry decking as I want a dry finished area underneath my deck. I would like to use LGS as my framework. Who do you recommend as a LGS supplier.

  12. Chris says:

    Thanks for this informative post, as well as your one at Deck Builder Magazine.

    I have a question, though. Trex Elevations says it can not be installed within .6 miles of a body of saltwater, and you mention in the comments that you would not use your standard LGS within range of salt water spray.

    What about a beachfront home, then? Set back, but still probably within that .6 minimum given by Trex. Would you rule out steel frame decking entirely, or is there a particular type of steel suited to the job?

    • Hi Chris,

      If you are remotely near saltwater (ie beachfront), you would definitely not want a steel frame deck. No galvanization that I know of can stand up to salt air. Go look at what happens to standard joist hangers on nearby decks. Stainless steel is the only option for metal near the ocean and it is not viable for framing due to cost.

  13. Mel Cooley says:

    I’m a homeowner with no construction skill. Though I found both your blog post and article in Professional Deck Builder Magazine highly informative, I would need a professional to install a steel framed deck. Do you know of any decking contractors in Portland Oregon who install steel decks? I would like a company that doesn’t exclusively use the Trex steel decking system.

    • Hi Mel,

      I would have to put some feelers out for you. Off the top of my head, I don’t have any colleagues I can think of in Portland.

      Try calling Kim at 360-709-9225 and see if he knows anyone. Tell him you spoke to me.


  14. Arash says:

    Hi Greg,

    I am going to build a garage deck in out backyard. We have many contraints and space limitations and based on what you provided here it seems like steel frame is the way to go. Do you recommend anyone in Washington DC area?


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