A 46-section interactive guide to diagnosing and repairing residential structural problems — how gravity and lateral loads travel through a house's framing, how to read foundation bearing pressure calculations, how to tell a structural crack from a cosmetic one, how differential settlement is surveyed and evaluated, how underpinning and pier retrofits actually work, residential retaining wall drainage and reinforcement, and how to assess seismic and fire-damaged structures. Every reference figure gets its own full-size slide so labels, tables, and calculation sheets stay legible.
Chapters 1–11 build the framing foundation: gravity and lateral load paths, house framing terminology, uplift versus gravity forces, load-bearing versus non-load-bearing walls, floor joist framing and span verification, and framing details at corners and floor openings. Chapters 12–18 cover foundations and bearing — bearing pressure calculations, existing-versus-new footing loads, stepped foundation bolting, basement wall construction, and anchor bolt and roof-to-foundation connections. Chapters 19–30 cover crack diagnosis — structural versus non-structural cracks, crack classification and mapping, and photo-based field diagnosis of cracks near windows, brick veneer, drywall corners, and fireplaces. Chapters 31–32 cover settlement surveying and angular distortion evaluation. Chapters 33–37 cover foundation repair, underpinning, helical piers, and pier retrofits. Chapters 38–39 cover residential retaining wall elevations and reinforcement. Chapters 40–46 cover seismic shear wall retrofit, post-earthquake story drift, and fire-damaged framing assessment including char depth analysis and load-path repair.
Use the Prev / Next buttons at the bottom, or press the arrow keys on your keyboard. Click the ☰ menu button in the top-right to open the table of contents and jump to any of the 46 sections directly. Each chapter's reference figure follows immediately after its text as its own dedicated slide, so diagrams, calculation sheets, and photos display at a fully readable size.
Home inspectors and structural engineers evaluating cracking, settlement, or fire and seismic damage in an existing house; contractors and homeowners trying to understand what a foundation repair proposal actually involves before hiring; and engineering students learning residential load paths, foundation bearing pressure, and diagnostic crack patterns through real calculation sheets and field photographs rather than abstract theory alone.
46 chapters spanning gravity and lateral load paths, house framing terminology, foundation bearing pressure and footing details, structural versus non-structural crack diagnosis, differential settlement and angular distortion evaluation, foundation underpinning and pier retrofit, residential retaining wall design, and seismic and fire damage assessment including char depth analysis and post-fire load path repair.
Structural warning signs include stair-step cracks in masonry, cracks running across a ceiling and down a wall, horizontal foundation cracks, large diagonal cracks, and any crack wider than about 1/10 in. Non-structural indicators include hairline cracks under 1/10 in. wide, isolated cracks confined to one block, and cracks that stay narrow and unchanged over time. A crack that is actively growing, widening, or displacing vertically warrants engineering evaluation regardless of its current size.
Angular distortion (β) normalizes differential settlement (Δ) by the structural distance (L) it occurs over: β = Δ/L. The same settlement spread over a longer distance produces far less distortion than the same settlement concentrated over a short distance, which is why angular distortion, not raw settlement alone, is the standard basis for judging whether observed movement is a genuine structural concern.
A helical pier is a steel shaft with helical plates advanced into the soil by torque, transferring an existing footing's load past weak or compressible soil down to a competent bearing stratum. A pier bracket attaches to the existing footing, and the pier's installation torque can be correlated directly to its verified load capacity, giving an immediate, field-verifiable quality check that some other underpinning methods cannot offer.
Char depth analysis quantifies how much of a fire-exposed member's cross-section remains effective, using a standard charring rate (commonly 0.375 in. per exposed side) to calculate a reduced effective depth and section modulus. The resulting capacity reduction is compared against the member's actual demand; where the reduction exceeds what the member's loading can tolerate, replacement rather than repair is the standard conclusion.
Disclaimer: This guide summarizes general residential structural diagnostics and repair concepts for educational purposes only. All calculation sheets, evaluation figures, and case values shown are illustrative examples and are not a substitute for a site-specific evaluation. Always consult a licensed structural engineer and the applicable building code (IRC, ASCE 7, ACI 318, NDS, and local amendments) before making any structural repair decision.