Stair Stringer Geometry: Rise, Run & Layout Guide
Master the fundamental mathematics of stair stringer layout. Learn how right-angle trigonometry and the Pythagorean theorem ensure exact stair fit.
Stair Building & Framing Guides
In-depth technical guides, IRC code explanations, framing square tutorials, and mathematical foundations for durable staircases.
IRC Building Code Stair Requirements & Tolerances
A comprehensive guide to the International Residential Code (IRC Section R311.7) for stair risers, minimum tread depth, and allowable variations.
How to Cut Outdoor Deck Stair Stringers: Framing Guide
Learn how to accurately mark and cut exterior pressure-treated stair stringers using a framing square and stair gauges without overcutting notches.
Stair Stringer Spacing & Load: 3 vs 4 Stringers
Determine exact on-center spacing for wood and composite decking treads. Avoid bouncy stairs and meet the 300-pound concentrated load code.
Throat Depth Calculation & 2×12 Stringer Lumber Guide
Calculate effective throat depth to prevent stringer failure. Understand why 2×10 lumber rarely leaves adequate solid wood after cutting.
The Blondel Formula & Stair Ergonomics Guide
Discover François Blondel’s classic 1675 formula (2R + T = 63 cm / 25 in) and why it remains the gold standard for comfortable residential staircases.
Pressure-Treated Wood vs Steel Stair Stringers
Compare cost, installation speed, lifespan, and aesthetic finishes between traditional pressure-treated wood stringers and powder-coated steel.
Securing Deck Stringers: Connectors vs Face Nailing
Learn approved structural attachment methods for connecting stringer tops to deck rim joists using structural screws, hanger brackets, and ledger drops.
How to Use a Framing Square & Stair Gauges
A practical carpenter guide to clamping brass stair gauges onto a steel framing square for rapid, error-free stringer layout.
The Bottom Step Rule: Deducting Tread Thickness
Avoid the most famous novice stair-building error. Understand the physics of dropping the bottom stringer cut by the exact thickness of the tread material.
Stair Headroom Clearance & Floor Opening Guide
Ensure adequate 80-inch vertical clearance along the entire stair flight. Learn how to calculate the required ceiling opening length in upper floors.
Building Concrete Landing Pads for Exterior Stairs
Step-by-step instructions for excavating, framing, and pouring a frost-resistant concrete landing pad for deck stairs to eliminate ground rot.