Metal framing changes the way a deck performs from the ground up.
As more projects move toward Class A assemblies, WUI-conscious construction, and longer-lasting exterior systems, builders are paying closer attention to what sits beneath the decking. While traditional pressure treated framing still has its place, aluminum and steel framing systems offer greater dimensional stability, cleaner finish details, and a more durable foundation for modern outdoor living projects.
The result is a cleaner structure, tighter finish details, and a framing package designed to support the level of materials being installed above it.
Continue below to explore aluminum vs. steel framing, WUI and Class A considerations, and where metal framing makes the most sense in today’s builds.
TimberTech Aluminum Framing is a complete system of components, from joists and posts, to ledgers and beams, all working together to create the best, longest-lasting deck. Aluminum Framing is compatible with every TimberTech Decking and Railing collection.
Class A Flame-Spread Rating
WUI Approved
Fortress Evolution: Steel Deck Framing
Look underneath most decks and you’ll see a weak link. Your decking and railing is engineered to last 25 years or more. So, why are you using wood framing? Choose Evolution steel deck framing. It's a smarter galvanized steel system designed by deck builders, for deck builders. The interlocking joist and ledger system lets you build sturdy, safe decks with less effort. Our powder-coated finish provides increased corrosion resistance and a more finished look.
WUI & Class A Considerations
Building Smarter. Building Safer.
As WUl requirements expand in areas like Austin and other wildfire-prone regions, more builders and designers are looking beyond the deck surface when specifying exterior assemblies.
Metal framing introduces a non-combustible structural component beneath the deck, helping support more fire-conscious outdoor living systems when paired with Class A-rated decking and railing products.
Non-Combustable Framing
Metal framing removes combustible lumber components beneath the deck surface.
WUI-Conscious Builds
Growing wildfire requirements are changing how exterior systems are designed and built.
Class A Assemblies
Pairs well with many Class A-rated decking and railing systems for a more fire-conscious assembly.
Rooftop & Multi-family
Increasingly used on elevated, commercial, and high-density projects.
Aluminum Framing
Best for premium residential decks, rooftops, and projects pairing with PVC or capped composite decking.
- Lightweight material puts less load on rooftop and elevated structures
- Naturally corrosion resistant — will not rust around pools, moisture, or coastal exposure
- Extremely straight material helps reduce waviness under composite decking
- Cleaner fascia lines and more consistent board spacing over time
- Easier to cut and handle on-site compared to steel
- Non-combustible framing option for WUI-conscious and Class A assembly builds
- Pairs well with modern outdoor living layouts and contemporary railing systems
Steel Framing
Best for larger decks, elevated structures, commercial applications, and projects requiring longer spans.
- Higher structural strength and rigidity than aluminum
- Better suited for larger framing layouts and demanding structural loads
- Creates a more solid feel underfoot on larger deck systems
- Powder-coated finish delivers a cleaner alternative to exposed treated lumber framing
- Helps reduce twisting, shrinking, and warping commonly seen with wood framing
- Strong option for multifamily, commercial, and elevated deck builds
- Non-combustible framing system that supports fire-conscious construction goals