You're looking to build a new deck or replace an old one, and you've heard about metal framing. Good for you. It's a smart move, especially here in St. Paul where wood frames can really take a beating from our crazy weather. But when it comes to metal, you've mainly got two choices: steel or aluminum. Which one's right for your deck? Let's talk about it.
Cost: Upfront vs. Long-Term
Let's get this out of the way first. Generally, aluminum deck framing is going to cost you more upfront than steel. Sometimes significantly more. That's just the nature of the material and the manufacturing process. Steel, especially galvanized steel, is a more common and often more affordable material to produce in the shapes we use for deck joists and beams.
Now, don't just stop there. When you're thinking about cost, you've got to look beyond the initial sticker price. What about maintenance? What about how long it's going to last? That's where the long-term value comes in, and it's where things get a bit more nuanced.
Durability: Fighting the Freeze-Thaw Cycle
This is where metal really shines compared to wood, no matter which metal you pick. Wood rots, warps, and splits, especially with our St. Paul freeze-thaw cycles. Metal doesn't. But there are differences between steel and aluminum.
Steel: It's incredibly strong. When you're talking about sheer load-bearing capacity, steel often wins. It's less likely to deflect or sag under heavy loads, which can be a big deal for larger decks or if you're planning on putting a hot tub on it. The main concern with steel is rust. You absolutely need galvanized steel, or some other robust coating, to protect it from corrosion. If that coating gets compromised, rust can set in, and that's not good. We've seen plenty of old steel structures around town, like bridges over the Mississippi, that show what happens when steel isn't properly protected.
Aluminum: This stuff is naturally corrosion-resistant. You don't have to worry about rust with aluminum, which is a huge plus in our wet and snowy climate. It's also lighter than steel, which can sometimes make installation a little easier, though that usually doesn't translate to a huge cost saving on labor for a typical residential deck. While strong, aluminum isn't quite as stiff as steel, so for the same span and load, you might need slightly larger aluminum members or closer spacing. This is something a good deck builder, like us at St Paul Deck Solutions, will factor into the design.
Maintenance: Set It and Forget It?
This is where aluminum really pulls ahead, in my opinion. With aluminum framing, once it's installed, you're pretty much done. You don't need to paint it, seal it, or worry about rust. It just sits there, doing its job, for decades.
Steel, even galvanized steel, needs a bit more attention over its lifetime. While modern galvanization is tough, any scratches or dings that expose the bare steel can eventually lead to rust. You might need to inspect it periodically and touch up any spots. It's not a huge chore, but it's more than you'd do for aluminum.
Appearance: Hidden or Highlighted?
For most decks, the framing isn't meant to be seen. It's underneath the decking, out of sight, out of mind. In that case, appearance isn't really a factor. Both steel and aluminum frames are designed to be functional, not decorative.
However, if you're building a deck with an exposed underside, maybe a second-story deck over a patio, then appearance might matter. Aluminum frames often have a cleaner, more finished look than galvanized steel, which can sometimes have a mottled or industrial appearance. Some aluminum systems are designed with aesthetics in mind, offering a more refined profile if it's going to be visible.
My Recommendation for St. Paul Homeowners
Look, if budget is your absolute top priority and you're willing to accept the very minor long-term maintenance of galvanized steel, then steel is a perfectly good option. It's strong, reliable, and will last a lot longer than wood.
But if you're asking me, for most St. Paul homeowners, especially those who want true 'set it and forget it' longevity and minimal fuss, aluminum deck framing is the better choice. Yes, it costs more upfront. I get that. But the natural corrosion resistance, the lighter weight, and the almost zero maintenance requirements make it a superior long-term investment, especially with our harsh Minnesota winters and humid summers. You won't have to worry about rust, and it'll outlast pretty much anything else you put on your property.
Think about it like this: you're building something that's going to be exposed to the elements year-round. You want the best protection against those elements. Aluminum gives you that peace of mind. It's a premium product, and it delivers premium performance. We've built plenty of decks with both, and while steel is solid, aluminum just feels a bit more bulletproof for our climate.
If you're thinking about a metal frame for your next deck project, give us a call. We can walk you through the specifics for your property, whether you're in Highland Park or on the bluffs of the East Side. We'll help you figure out what makes the most sense for your home and your budget.