Introduction
Abstract formulas stick better when you watch them work on something concrete — what does a full beam-load workflow look like on a realistic project, from first measurement to the engineer’s desk? This case study follows a common residential scenario end to end: the load buildup, the calculator runs, the material comparison, the budget, and the professional handoff. Every number is worked in both imperial and metric.
Hypothetical case study — illustrative example, not a real project. The scenario, dimensions, loads, and costs below are invented to demonstrate the workflow. They are not a design, not a recommendation, and not a substitute for project-specific engineering.
The Beam Load Calculator performs every calculation shown here — this walkthrough demonstrates the judgment around the tool: which loads to include, how to sanity-check outputs, and when to hand off. For the load-buildup method in general, see the estimating guide.
The Scenario
A homeowner wants to remove a 16 ft load-bearing wall between a kitchen and living room on the ground floor of a two-story wood-frame house, replacing it with a beam. Above the wall: the second floor (bedrooms) and an attic with light storage. The plan: a beam spanning the 16 ft opening, supported at each end by new posts on new footings in the basement.
Hypothetical case study — illustrative example, not a real project. Dimensions and loads are chosen for demonstration; a real project needs as-built measurements and engineer-verified loads.
Step 1: Measure the Span
The opening measures 16 ft clear. Allowing 6 inches of bearing at each end, the structural span is 16.5 ft center-to-center of supports — the number the formulas want. (In metric: 5.03 m.) The number-one span mistake — measuring the opening instead of the span — is documented in the common mistakes guide; this case study measures it right.
Step 2: Build the Loads
The beam carries two floors of tributary area. Joists span 14 ft each side of the wall, so the tributary width is 7 ft per side — 14 ft total. Wait: for a wall position, the beam picks up half the joist span from each side: 7 + 7 = 14 ft of tributary width.
Second floor (bedrooms): dead 12 psf (framing, subfloor, finishes) + live 30 psf (sleeping rooms) = 42 psf. Line load: 42 × 14 = 588 lb/ft.
Attic (light storage): dead 8 psf + live 20 psf = 28 psf. Line load: 28 × 14 = 392 lb/ft.
Total UDL: 588 + 392 = 980 lb/ft, rounded up to 1,000 lb/ft for planning conservatism. Self-weight will be iterated in once a beam is selected.
Step 3: Run the Calculator
Span L = 16.5 ft, UDL w = 1,000 lb/ft, simply supported:
Reactions: R = wL/2 = 1,000 × 16.5 / 2 = 8,250 lb per support.
Maximum moment: M = wL²/8 = 1,000 × 272.25 / 8 = 34,031 lb-ft at midspan.
Equilibrium check: total load = 1,000 × 16.5 = 16,500 lb; reactions sum to 16,500 lb. Balanced.
Metric cross-check — span 5.029 m, w = 14.594 kN/m: R = 14.594 × 5.029 / 2 = 36.70 kN (36.70 × 224.81 = 8,250 lb ✓); M = 14.594 × 5.029² / 8 = 14.594 × 25.291 / 8 = 46.14 kN·m (46.14 × 737.56 = 34,031 lb-ft ✓). Both systems agree.
Step 4: Compare Material Options
With demands of 8,250 lb per support and ~34,000 lb-ft of moment, the homeowner prices two candidate approaches (material-only, typical US ranges):
| Option | Material cost (17 ft stock) | Depth implication | Installation notes |
|---|---|---|---|
| Built-up LVL | 17 ft × $18–$25 = $306–$425 | Deepest — check headroom | Heavy; multi-person lift |
| Structural steel W-shape | 17 ft × $30–$45 = $510–$765 + fabrication | Shallowest — preserves headroom | Crane or gantry; welded/bolted connections |
The moment is large enough that solid lumber is not a serious candidate — exactly the kind of early elimination that planning math enables. The final choice between LVL and steel, including the actual section sizes, belongs to the engineer; the material guide compares the options’ behavior in detail.
Step 5: Budget the Project
A hypothetical planning budget (typical US ranges; regional costs vary significantly):
- Beam material: $306–$765 depending on option.
- Installation (retrofit, shoring, finish repair): $2,500–$5,000 — the dominant line.
- Two post-and-footing assemblies (each carrying 8,250 lb reactions): $500–$1,600.
- Engineering + permit: $500–$1,500 for a two-floor load path.
- Planning total: $3,800–$8,900.
The reactions drove the footing cost; the moment drove the material shortlist; the retrofit condition drove the labor. Every budget line traces back to a calculated number — the full budgeting method is in the cost guide.
Step 6: Hand Off to the Engineer
The homeowner’s package for the structural engineer:
- Dimensioned sketch: 16.5 ft span, support locations, 14 ft tributary width, both floors noted.
- Load buildup: 42 psf second floor + 28 psf attic, rounded to 1,000 lb/ft UDL, with sources.
- Calculator outputs: R = 8,250 lb per support, M = 34,031 lb-ft, both unit systems.
- Material preference: LVL vs. steel shortlist with headroom constraints noted.
- Photos of existing wall, basement below, and attic above.
The engineer verifies the loads, applies code load combinations and deflection checks, selects the section, designs shoring, posts, footings, and connections, and stamps the permit set. The homeowner’s planning work becomes a fast verification instead of a from-scratch investigation — the economics of the DIY vs pro division of labor in action.
What This Case Study Demonstrates
- Workflow order matters: measure → build loads → calculate → compare → budget → hire. Skipping ahead (pricing beams before knowing loads) is the classic planning failure.
- Every number earns its keep: the span squared drives the moment; the tributary width drives the UDL; the reactions drive the footings.
- Conservatism is cheap at the planning stage: rounding 980 to 1,000 lb/ft cost nothing and bought margin.
- The handoff is the product: the deliverable of DIY analysis isn’t a beam choice — it’s a credible package an engineer can verify quickly.
Related Guides
- Beam Load Estimating Guide — the tributary-width buildup method used here.
- DIY vs Pro — the division of labor this case study follows.
- Beam Cost Guide — the budgeting method behind the project total.
- Complete Guide — the formulas and worked examples behind the math.
- Beam Load Checklist — the verification pass before any handoff.
Run Your Own Scenario
This was a hypothetical walkthrough — your project has its own span, its own loads, its own constraints. Follow the same six steps: measure the true span, build the loads honestly, run them through the Beam Load Calculator, compare materials, budget completely, and hand a documented package to a licensed structural engineer. The workflow is the lesson; the numbers are yours to compute.
Disclaimer: Hypothetical case study — illustrative example, not a real project. All dimensions, loads, and costs are invented for demonstration and are not design values. Calculator results are planning estimates only; structural design requires a licensed structural engineer and must comply with your local building code and authority having jurisdiction.
