What do you put under stair stringers?
Beyond the Basics: Comprehensive Support for Stair Stringers
Brief Summary
Under stair stringers, you’ll need sturdy support framing, typically 2×6 or 2×8 lumber, securely attached to the main structure. When building on a deck, add blocking below the rim joist for extra support. But there’s more to consider: load-bearing capacity, moisture protection, building codes, and even staircase design trends influence what goes beneath those stringers.
Expanded Answer: Stair Stringer Support, Building Codes, and Design Considerations
The Foundation of a Staircase
Stair stringers aren’t just about holding up steps; they’re the backbone of safe ascent and descent. So, what goes under them matters greatly. It’s about more than just a few beams; it’s about engineering a structure that supports weight, resists movement, and meets stringent building codes.
Support Framing: Beyond the 2×6
While 2×6 or 2×8 lumber is common, it’s not one-size-fits-all. Staircase length, expected load (think people, furniture moving, etc.), and local codes all dictate the right size. Longer spans or heavy-duty use may call for larger lumber or even steel. It’s about matching the support to the demand.
Blocking: Not Just for Decks
Blocking adds a crucial layer of security, especially on decks where the rim joist might not be enough to anchor stringers solidly. But even indoors, blocking can reinforce connections and prevent squeaks down the line. Think of it as an extra handshake between the stairs and the building itself.
Building Codes: The Safety Net
U.S. building codes, like the IRC, aren’t suggestions; they’re law. They cover everything from stringer size to tread depth, ensuring your stairs are safe for everyone. Ignoring them risks not only structural failure but also legal trouble. It’s worth consulting local authorities before you even cut the first board.
Load-Bearing: More Than Just Weight
It’s not just about how much the stairs weigh; it’s about what they’ll carry. People, furniture, even a rambunctious dog all add to the ‘live load’. The structure beneath must handle it all without budging. Overbuilding slightly is often wise, especially in high-traffic areas.
Moisture & Materials: The Silent Threat
Outdoors, moisture is the enemy. Pressure-treated lumber or rot-resistant alternatives are a must. Even indoors, basements or humid climates need consideration. The wrong material rots, weakens, and compromises safety. It’s an investment in longevity.
Design Trends: Impact on Support
Modern ‘floating’ stairs or minimalist designs may look sleek, but they put extra demands on hidden support. Steel, clever engineering, or even reinforced walls may be needed. It’s a reminder that form and function must go hand-in-hand.
Permits & Inspections: Don’t Skip Them
Depending on your project, permits and inspections may be mandatory. This isn’t red tape; it’s a safety check. An expert eye catches potential flaws early, saving headaches later. It’s peace of mind knowing your stairs are up to code.
Beyond the Basics: Additional Factors
- Stringer Type: Cut stringers (notched) have different support needs than solid ones.
- Landing Points: Mid-stair landings affect stringer span and thus, support requirements.
- Seismic Zones: Earthquake-prone areas may have stricter codes for stair construction.
Conclusion
What goes under your stair stringers isn’t just about holding them up; it’s about building a safe, sturdy, and code-compliant staircase that lasts. It’s an investment in your home and the well-being of those who use it. Don’t cut corners here; quality support is the foundation of a well-built staircase.