Flood Damage Replacement Cost Estimator

ANA›Life Services Authority›National Calculator Authority›Flood Damage Replacement Cost Estimator

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Flood Damage Replacement Cost Estimator

Estimates the replacement cost of flood-damaged property using FEMA depth-damage functions, regional construction costs, and structure characteristics.

Structure Type

Single-Family Residential (1-story, no basement) Single-Family Residential (2-story, no basement) Single-Family Residential (with basement) Mobile / Manufactured Home Commercial / Retail Industrial / Warehouse

Total Finished Floor Area (sq ft)

Flood Depth Above First Floor (ft) (use negative for below-floor)

Replacement Cost Value of Structure ($)

Contents Value ($) (optional, 0 to skip)

Regional Cost Multiplier

Low-Cost Region (e.g. rural Midwest/South) — 0.82× National Average — 1.00× Moderate-Cost Region (e.g. Southeast coast) — 1.15× High-Cost Region (e.g. Mid-Atlantic, Gulf Coast) — 1.30× Very High-Cost Region (e.g. NYC, San Francisco) — 1.55×

Year Structure Built

Foundation Type

Slab-on-Grade Crawlspace Full Basement Elevated / Pier & Beam

Calculate Replacement Cost Enter values above to estimate flood damage replacement cost.

function floCalc() { // ── Inputs ────────────────────────────────────────────────────────────── var structType = parseFloat(document.getElementById('flo-struct-type').value); var sqft = parseFloat(document.getElementById('flo-sqft').value); var floodDepth = parseFloat(document.getElementById('flo-flood-depth').value); var rcv = parseFloat(document.getElementById('flo-rcv').value); var contents = parseFloat(document.getElementById('flo-contents').value) || 0; var regionMult = parseFloat(document.getElementById('flo-region').value); var yearBuilt = parseFloat(document.getElementById('flo-age').value); var foundation = document.getElementById('flo-foundation').value; var resultDiv = document.getElementById('flo-result');

// ── Validation ─────────────────────────────────────────────────────────── var errors = []; if (isNaN(sqft) || sqft 2025) errors.push("Year built must be between 1800 and 2025."); if (errors.length > 0) { resultDiv.innerHTML = '' + errors.join('') + ''; return; }

// ── FEMA Depth-Damage Functions (% of structure value) ────────────────── // Source: FEMA Flood Damage Functions (Hazus-MH 4.2, Table 7.11 / USACE IWR) // Depth breakpoints: -4, -2, 0, 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 24 ft // Damage % for each structure type at each depth var depthBreaks = [-4, -2, 0, 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 24];

// Damage fractions (0–1) per structure type (1–6) at each depth break var damageTables = { 1: [0.00, 0.00, 0.04, 0.08, 0.14, 0.24, 0.34, 0.43, 0.52, 0.59, 0.65, 0.70, 0.74, 0.77, 0.82], 2: [0.00, 0.00, 0.02, 0.05, 0.09, 0.16, 0.23, 0.30, 0.37, 0.43, 0.48, 0.53, 0.57, 0.60, 0.65], 3: [0.00, 0.02, 0.06, 0.11, 0.18, 0.28, 0.38, 0.47, 0.55, 0.62, 0.67, 0.72, 0.76, 0.79, 0.84], 4: [0.00, 0.00, 0.08, 0.15, 0.25, 0.40, 0.55, 0.65, 0.72, 0.78, 0.83, 0.87, 0.90, 0.92, 0.95], 5: [0.00, 0.00, 0.03, 0.07, 0.12, 0.20, 0.28, 0.36, 0.43, 0.50, 0.56, 0.61, 0.65, 0.68, 0.73], 6: [0.00, 0.00, 0.01, 0.03, 0.06, 0.11, 0.17, 0.23, 0.29, 0.35, 0.40, 0.45, 0.49, 0.52, 0.57] };

// Linear interpolation between depth breakpoints function interpolateDamage(depth, table) { if (depth = depthBreaks[depthBreaks.length - 1]) return table[table.length - 1]; for (var i = 0; i = depthBreaks[i] && depth 20) { ageAdj = 1.0 + Math.min((age - 20) * 0.005, 0.15); }

// ── Adjusted Structure Damage Fraction ─────────────────────────────────── var adjDamageFraction = Math.min(baseDamageFraction * foundMult * ageAdj, 1.0);

// ── Structure Replacement Cost ──────────────────────────────────────────── // Damaged portion × RCV × regional multiplier var structDamageCost = adjDamageFraction * rcv * regionMult;

// ── Contents Damage ─────────────────────────────────────────────────────── // FEMA contents damage functions (simplified: ~1.4× structure damage fraction for residential, // ~1.1× for commercial, capped at 1.0) // Source: Hazus-MH 4.2 Table 7.14 var contentsDamageMultipliers = { 1: 1.40, 2: 1.30, 3: 1.45, 4: 1.50, 5: 1.10, 6: 0.90 }; var contentsFraction = Math.min(baseDamageFraction * (contentsDamageMultipliers[structType] || 1.2), 1.0); var contentsDamageCost = contentsFraction * contents;

// ── Cleanup & Mitigation Costs ──────────────────────────────────────────── // FEMA estimates cleanup at $3–$8/sq ft depending on depth; use depth-scaled formula // Cleanup cost = sqft × base_rate × depth_factor × regional_mult var baseCleanupRate = 3.50; // $/sq ft baseline var depthFactor = 1.0 + Math.max(floodDepth, 0) * 0.08; // +8% per foot above floor var cleanupCost = sqft * baseCleanupRate * depthFactor * regionMult;

// ── Mold Remediation ───────────────────────────────────────────────────── // Triggered when flood depth > 0 ft; cost scales with depth and area // Source: EPA / IICRC S520 Standard var moldCost = 0; if (floodDepth > 0) { var moldRate = 2.00 + floodDepth * 0.25; // $/sq ft, increases with depth moldCost = sqft * moldRate * regionMult; }

// ── Total Replacement / Repair Cost ────────────────────────────────────── var totalCost = structDamageCost + contentsDamageCost + cleanupCost + moldCost;

// ── 50% Rule Check (NFIP Substantial Damage) ───────────────────────────── var substantialDamage = (structDamageCost / rcv) >= 0.50;

// ── Formatting ──────────────────────────────────────────────────────────── function fmt(n) { return '$' + n.toFixed(2).replace(/\B(?=(\d{3})+(?!\d))/g, ','); } function pct(n) { return (n * 100).toFixed(1) + '%'; }

var sdWarning = substantialDamage
? '' +
'⚠ NFIP Substantial Damage Alert: Estimated structure damage (' +
pct(structDamageCost / rcv) + ' of RCV) meets or exceeds the 50% threshold. ' +
'Under NFIP regulations, the structure may need to be brought into full compliance with current floodplain management standards before repair.'
'';
resultDiv.innerHTML =
'### Flood Damage Replacement Cost Estimate
' +
'' +
'Base Structure Damage Fraction (FEMA)' +
'' + pct(baseDamageFraction) + '' +
'Adjusted Damage Fraction (foundation + age)' +
'' + pct(adjDamageFraction) + '' +
'Structure Replacement / Repair Cost' +
'' + fmt(structDamageCost) + '' +
(contents > 0
? 'Contents Damage Cost' +
'' + fmt(contentsDamageCost) + ''
'') +
'Cleanup & Debris Removal' +
'' + fmt(cleanupCost) + '' +
(moldCost > 0
? 'Mold Remediation' +
'' + fmt(moldCost) + ''
'') + 'Total Estimated Replacement Cost' + '' + fmt(totalCost) + '' + '' + sdWarning + '* Estimates are based on FEMA Hazus-MH depth-damage functions and USACE IWR data. Actual costs may vary. Consult a licensed adjuster for official claims.

'; }

#### Formulas Used

1. Base Damage Fraction — Linear interpolation of FEMA Hazus-MH 4.2 depth-damage tables by structure type and flood depth above first floor (ft).

2. Adjusted Damage Fraction

AdjFraction = min(BaseFraction × FoundationAdj × AgeAdj, 1.0)

FoundationAdj: Slab=1.00, Crawlspace=1.05, Basement=1.18, Elevated=0.72 AgeAdj = 1.0 + min((Age − 20) × 0.005, 0.15) [if Age > 20 years] 3. Structure Replacement Cost

StructCost = AdjFraction × RCV × RegionalMultiplier 4. Contents Damage Cost

ContentsFraction = min(BaseFraction × ContentsMult, 1.0) ContentsCost = ContentsFraction × ContentsValue ContentsMult: Residential ≈ 1.30–1.50, Commercial ≈ 1.10, Industrial ≈ 0.90 5. Cleanup & Debris Removal

CleanupCost = SqFt × $3.50 × (1 + max(Depth,0) × 0.08) × RegionalMult 6. Mold Remediation (when depth > 0 ft)

MoldCost = SqFt × ($2.00 + Depth × $0.25) × RegionalMult 7. Total Cost

Total = StructCost + ContentsCost + CleanupCost + MoldCost 8. NFIP Substantial Damage Rule

Substantial Damage = (StructCost / RCV) ≥ 50%

#### Assumptions & References

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