Land Grading and Drainage Cost Calculator: Slope Correction, French Drains, and Erosion Control ROI

Why Drainage Problems Are a Silent Home Killer

Water is patient. It doesn't announce itself the way a burst pipe does. Instead, it seeps, pools, and slowly undermines your foundation over months and years—until you're looking at a $15,000 structural repair bill that a $2,000 drainage fix would have prevented. Poor yard drainage is one of the most underestimated threats to residential property values, yet it's also one of the most solvable problems in home improvement.

This guide walks you through the true cost of land grading, French drain installation, and erosion control solutions. More importantly, it shows you how to calculate whether these investments actually pay off—because understanding the return on investment of drainage work is just as important as understanding the upfront price tag.

The Hidden Damage Cascade

Most homeowners don't connect the dots between a perpetually soggy corner of the yard and the hairline crack forming in their basement wall. But drainage professionals see this pattern constantly. Poor surface drainage creates a chain reaction of damage that compounds over time:

Hydrostatic pressure: When water saturates the soil around your foundation, it exerts lateral pressure on basement and crawlspace walls. Even well-built foundations weren't designed to withstand sustained hydrostatic loading. The result is bowing walls, horizontal cracks, and eventually structural failure.
Soil heaving and settlement: Repeatedly wet and dry soil cycles cause expansion and contraction beneath slabs, patios, driveways, and even the footings your home rests on. This uneven settlement is why your garage floor develops that telltale slope or your front steps start to pull away from the house.
Mold and air quality: Moisture that infiltrates a crawlspace or basement doesn't stay there. Studies from the EPA estimate that up to 40% of the air in your home's living spaces originates from below grade. A chronically wet crawlspace is essentially a mold incubator feeding directly into the air your family breathes.
Landscaping and hardscape destruction: Pooling water drowns established trees and shrubs, erodes topsoil, and undermines retaining walls and paving—repairs that typically run $500 to $5,000 per incident.

Warning Signs You Shouldn't Ignore

The challenge is that drainage damage is gradual enough that homeowners normalize the symptoms. If you notice any of the following, you're likely already in the early-to-middle stages of water damage:

Standing water that takes more than 24–48 hours to drain after a moderate rainfall
Efflorescence (white mineral deposits) on basement walls or concrete block
Musty odors in basements, crawlspaces, or even first-floor rooms
Soft, spongy lawn areas that stay wet even during dry spells
Soil pulling away from the foundation or grading that slopes toward the house
Wood rot on sill plates, band joists, or deck posts at or near ground level

Rule of thumb: For every year a significant drainage problem goes unaddressed, remediation costs tend to increase by 15–25%. A $3,000 grading correction today can easily become a $12,000–$20,000 foundation repair within five years.

Why This Problem Is So Widespread

Poor drainage isn't just a problem for older homes or properties in rainy climates. Several modern factors are actively making it worse across the country. Suburban development compacts surrounding soil and increases runoff from neighboring properties. Climate change is intensifying rainfall events—more rain falling faster than the ground can absorb. And ironically, home additions, patios, and hardscaping projects frequently alter the original site grading without homeowners realizing it.

The good news: drainage problems are almost always fixable, and the solutions have a measurable, calculable return on investment. Understanding the cost structure—and the damage it prevents—is the first step toward making a smart, financially sound decision.

Understanding Land Grading: The Foundation of All Drainage Solutions

Before any French drain or erosion barrier does its job, the land itself needs to direct water away from your home. That's grading—the reshaping of soil to create deliberate slopes that guide water flow.

The Golden Rule of Yard Slope

The International Residential Code (IRC) and most landscape architects agree on a minimum grading standard: the ground should slope away from your foundation at a rate of 6 inches over the first 10 feet. That's a 5% grade. Beyond 10 feet, even a 2% grade (roughly 2.5 inches per 10 feet) is generally sufficient to keep water moving away from the structure.

Here's the quick formula to calculate your existing grade:

Grade Percentage = (Rise ÷ Run) × 100
Example: If the ground drops 3 inches over 10 feet, your grade is (3÷120) × 100 = 2.5%

A grade below 1% near your foundation is a red flag. Water will pool, saturate the soil, and create hydrostatic pressure against your basement walls or slab.

What Does Land Grading Actually Cost?

Grading costs vary based on the size of the area, the severity of the slope correction needed, soil type, and whether fill dirt or topsoil must be imported.

Basic regrading (minor slope correction): $500–$1,500 for a typical residential yard under 5,000 sq ft
Moderate grading (significant reshaping): $1,500–$5,000 for areas requiring significant soil movement or fill
Major grading (retaining walls or terracing included): $5,000–$20,000+ when structural elements are needed
Fill dirt cost: $8–$15 per cubic yard delivered; expect to need 2–10 cubic yards for average corrections
Topsoil (for finish grading): $15–$30 per cubic yard

To estimate the cubic yards of fill dirt you need, use this formula:

Cubic Yards = (Area in sq ft × Depth of fill in feet) ÷ 27
Example: Filling a 500 sq ft area to an average depth of 4 inches (0.33 ft): (500 × 0.33) ÷ 27 = approximately 6.1 cubic yards

Use our Land Grading Cost Calculator at unreliant.com to plug in your specific measurements and get an instant estimate based on your yard's dimensions and correction depth.

French Drains: When Grading Isn't Enough

Sometimes regrading alone can't solve a drainage problem—especially when you have a yard that collects runoff from neighboring properties, a high water table, or impermeable clay soil. That's where French drains become the workhorse solution.

How a French Drain Works

A French drain is a gravel-filled trench containing a perforated pipe. Water enters the trench through the gravel, flows into the pipe, and is carried away to a discharge point—a street drain, dry well, or lower area of the property. The system relies on gravity, so proper slope within the drain itself is critical.

Minimum slope for a French drain: 1% grade (1 inch of drop per 8 feet of run). A 0.5% slope is the absolute minimum for any drainage to occur; anything less and water will stagnate in the pipe.

French Drain Installation Costs

French drain pricing is typically quoted per linear foot. Here's what you can expect:

Basic DIY French drain: $10–$15 per linear foot (materials only: pipe, gravel, landscape fabric)
Professionally installed French drain: $20–$40 per linear foot
Interior basement French drain (perimeter system): $50–$100 per linear foot—this involves jackhammering concrete
Dry well addition: $1,000–$3,500 depending on size and soil permeability
Average residential exterior French drain (50–100 linear feet): $1,500–$6,000 installed

Sizing Your French Drain: A Practical Formula

The pipe diameter matters. Undersized pipe will back up during heavy rains, defeating the purpose entirely. Use the Rational Method as a simplified guide:

Q = C × i × A
Where Q = flow rate (cubic feet per second), C = runoff coefficient (0.3 for lawn, 0.9 for pavement), i = rainfall intensity (inches/hour), A = drainage area (acres)

For most residential applications, a 4-inch perforated pipe handles drainage areas up to about 5,000 square feet in moderate rainfall. A 6-inch pipe handles up to 10,000 square feet. If your property collects runoff from neighboring lots, size up by at least one pipe diameter.

Real-World French Drain Scenario

Imagine a homeowner in a suburban neighborhood with a 60-foot section of yard that consistently floods after moderate rain, sitting adjacent to a neighbor's property that drains toward them. The problem area is roughly 3,000 square feet of lawn.

Required trench: 60 linear feet, 18 inches deep, 12 inches wide
Gravel needed: approximately 4.4 cubic yards at $35/yd = $154
4-inch perforated pipe: 60 feet at $0.75/ft = $45
Landscape fabric: 1 roll at $30
Labor (DIY): $0 / (Professional): ~$1,200–$2,400
Total DIY cost: ~$350–$500
Total professional cost: ~$1,500–$3,000

That $3,000 investment protects against what? Let's get to the ROI calculation.

Calculating the ROI of Drainage Improvements

This is where most homeowners stop short. They look at the cost of fixing drainage but never quantify what they're protecting. The ROI framework for drainage work involves three variables: cost of the fix, cost of the damage avoided, and probability of that damage occurring.

The Cost of Foundation Damage

Foundation repair is one of the most expensive home repairs there is. Here are realistic cost benchmarks:

Minor foundation crack repair (epoxy injection): $500–$2,500
Moderate settling with piering: $5,000–$15,000
Major foundation replacement (severe case): $20,000–$100,000+
Basement waterproofing (interior system): $5,000–$15,000
Mold remediation from water intrusion: $1,500–$10,000

Water-related foundation damage is not rare. According to industry estimates, approximately 60% of U.S. homes experience some form of water infiltration, and inadequate drainage is the leading cause of basement moisture problems.

The ROI Formula for Drainage Work

ROI = [(Damage Cost Avoided × Probability of Damage) – Cost of Fix] ÷ Cost of Fix × 100

Let's apply this to our French drain scenario:

Cost of fix: $2,500 (professional French drain)
Estimated damage if not fixed (foundation settling + water intrusion): $12,000
Estimated probability of damage occurring within 10 years without fix: 60%
Expected damage cost: $12,000 × 0.60 = $7,200
ROI = [($7,200 – $2,500) ÷ $2,500] × 100 = 188% ROI

That's nearly 3x your money back in avoided repairs—and that's before factoring in property value preservation or the avoided stress of a major home repair.

Property Value Impact

Real estate agents consistently report that evidence of drainage problems—water stains, efflorescence on concrete, soft spots in the yard—can reduce a home's sale price by 10–25% or kill deals entirely at inspection. On a $350,000 home, that's $35,000–$87,500 in lost value. Even a $5,000 comprehensive drainage solution looks like a bargain against that exposure.

Conversely, proactively documented drainage improvements can be a selling point that supports your asking price. Buyers in flood-prone or clay-soil areas will pay a premium for a home with demonstrated water management.

Erosion Control: Protecting Your Investment After Grading

Grading moves soil. French drains redirect water. But neither solution prevents the soil itself from washing away—that's the job of erosion control. And erosion is expensive to ignore: the American Society of Civil Engineers estimates that erosion-related damage costs U.S. property owners billions annually.

Understanding Erosion Risk: The RUSLE Framework

Engineers use the Revised Universal Soil Loss Equation (RUSLE) to estimate erosion potential, but homeowners can use a simplified version to gauge their risk level:

Erosion Risk Score = Slope Steepness × Soil Erodibility × Rainfall Intensity × (1 – Vegetation Cover)

Rate each factor from 1–5 and multiply. A score above 50 means you need active erosion control measures. Key risk factors include:

Slopes exceeding 10% grade
Sandy or silty soils (loam and clay are more resistant)
Bare soil exposed for more than 2 weeks
High-intensity rainfall regions (Southeast, Midwest storm belt)

Erosion Control Solutions and Their Costs

Hydroseeding is one of the most cost-effective erosion control solutions for slopes and large areas. A slurry mixture of grass seed, mulch, fertilizer, and tackifier is sprayed onto bare soil.

Cost: $0.06–$0.20 per square foot ($2,600–$8,700 per acre)
Best for: Large open slopes, post-grading revegetation
Effectiveness timeline: Germination in 5–14 days, full coverage in 4–8 weeks

Erosion control blankets (ECBs) are biodegradable mats made from straw, coir, or wood fiber that hold soil in place while vegetation establishes.

Cost: $0.15–$0.50 per square foot installed
Best for: Slopes up to 3:1 (33% grade), channel banks
Lifespan: 1–3 years before biodegradation (by which time roots do the job)

Riprap (rock lining) is used in concentrated flow areas where water velocity is too high for vegetation.

Cost: $35–$75 per cubic yard installed
Best for: Drainage swales, downspout discharge points, channel edges
Rule of thumb: Use riprap where flow velocity exceeds 5 ft/second

Retaining walls are the heavy-duty solution for slopes exceeding 2:1 grade.

Timber walls: $15–$25 per sq ft of face
Concrete block (Allan Block-style): $25–$45 per sq ft of face
Poured concrete or stone: $40–$80+ per sq ft of face
Engineering required for walls over 4 feet in most jurisdictions

Native ground cover plantings are the long-term biological solution—deep-rooted natives like creeping juniper, crown vetch, or native fescues can reduce erosion by 70–95% once established.

Installed cost: $1.50–$4.00 per square foot
Long-term maintenance: Minimal once established
Best for: Slopes, rain garden edges, disturbed areas

Erosion Control ROI Calculation

Consider a homeowner with a 1,500 sq ft sloped area behind their home. Without intervention, that slope is losing an estimated 2–4 cubic yards of soil annually to runoff—sediment that clogs their drainage system, kills lawn areas downslope, and gradually undermines a small retaining wall.

Annual cost of damage (lost soil, clogged drain cleaning, lawn repair): ~$800/year
Cost of hydroseeding + erosion blanket installation: ~$1,200
Simple payback period: 1,200 ÷ 800 = 1.5 years

After 5 years, the homeowner has saved approximately $4,000 in avoided damage costs on a $1,200 investment—a 233% cumulative ROI.

Putting It All Together: A Full Drainage Cost Estimate

Let's walk through a comprehensive drainage improvement plan for a hypothetical suburban home on a ½-acre lot with a basement, clay soil, and a 15% rear slope:

Problem Assessment

Foundation side grading: negative grade (slopes toward house) on two sides
Rear yard: standing water 24+ hours after moderate rain
Rear slope: active erosion, bare patches visible
Downspouts: discharging against foundation

Damage Avoidance Value (10-Year Horizon)

Foundation repair risk mitigation: $8,000–$20,000 in expected damage avoided (60% probability × $15,000 midpoint estimate = $9,000)
Basement waterproofing avoided: $7,000 (75% probability × $9,500 midpoint = $7,125)
Annual erosion/landscaping repair avoided: $600/yr × 10 years = $6,000
Property value preservation: Conservative estimate $10,000–$30,000
Conservative total damage avoidance: ~$22,000–$42,000

10-Year ROI: 278%–622%

Use the Drainage ROI Calculator on unreliant.com to model your own property's specific numbers—input your home value, risk factors, and proposed solution costs to get a personalized ROI estimate.

DIY vs. Professional: When to Call in the Pros

Not every drainage project requires a contractor. Here's a practical decision guide:

Confident DIY Territory

Adding soil to correct minor negative grades (less than 2-inch correction needed)
Installing downspout extensions and splash blocks
Digging and installing a simple French drain under 30 feet in accessible soil
Laying erosion control blankets and seeding
Installing surface swales in open lawn areas

Hire a Professional When...

Foundation is already showing cracks or settling
The drainage area includes utilities (always call 811 before digging)
You need to trench near trees (root damage risk)
The project requires permits (retaining walls over 30 inches, major earthwork)
You're dealing with a high water table requiring sump pump integration
Neighboring properties are involved (drainage easements, legal liability)

Get a minimum of three contractor quotes and ask specifically about their warranty on drainage work—quality contractors typically offer 1–2 year workmanship warranties on French drain installation.

The Real Cost Comparison: DIY Savings vs. Hidden Risks

The financial case for DIY drainage work can look compelling on paper. A 50-foot French drain that costs $1,500–$2,500 professionally installed might run you $300–$600 in materials if you do it yourself—a potential savings of $1,000 or more. But those numbers only hold up when the job is done correctly the first time.

The most common and costly DIY drainage mistake is improper slope on the drain pipe. A French drain requires a consistent minimum 1% grade (1 inch of drop per 8 feet of run) to move water effectively. Without a laser level or transit, many homeowners eyeball this—and even a small error over 50 feet can create a low spot that collects sediment, backs up during heavy rain, and fails within 2–3 years. A professional re-installation after a failed DIY attempt typically costs more than the original quote, because the contractor must now excavate and remove your previous work.

Rule of Thumb: If the project involves more than a single drainage pathway, affects more than 500 square feet of catchment area, or requires integrating with an existing system, the complexity risk usually outweighs the DIY savings.

How to Vet a Drainage Contractor

Not all landscapers are qualified to design and install drainage systems. When interviewing contractors, go beyond price and ask these specific questions:

"Can you show me the planned outlet location and how water exits the property?" — A contractor who can't clearly answer this hasn't fully scoped the project.
"What pipe diameter and aggregate size will you use?" — For residential French drains, 4-inch perforated pipe in clean ¾-inch crushed stone wrapped in filter fabric is the standard. Anything less is a red flag.
"Will you pull the necessary permits?" — In many municipalities, grading that alters natural water flow requires a stormwater permit. A contractor who dismisses this question may be cutting corners.
"What does your warranty cover, and what voids it?" — Some warranties exclude damage from root intrusion or sediment buildup, which are actually common failure points.

A Practical DIY Skill Assessment

Before committing to a DIY drainage project, honestly evaluate your readiness across three dimensions:

Tools: Do you have or can you rent a trenching machine, a laser level, and a plate compactor? Manual trenching 30 feet in clay soil is a full-day physical undertaking for two people.
Time: A 40-foot French drain installation realistically takes 6–10 hours for an experienced DIYer—and 12–16 hours if it's your first attempt. Factor in material runs and backfill compaction.
Soil conditions: Sandy or loamy soil is forgiving. Rocky soil or heavy clay significantly increases difficulty, tool requirements, and time. If your test dig with a shovel hits resistance within 6 inches, budget for a power trencher rental ($200–$350/day).

The sweet spot for confident DIY work is a straightforward, single-run French drain in accessible soil with a clear, code-compliant outlet—such as daylighting into a slope or connecting to a street curb drain. If your project checks all those boxes, the savings are real and the risk is manageable.

Maintenance: Protecting Your Drainage Investment

A French drain that isn't maintained will fail. Silt migration, root intrusion, and gravel compaction reduce performance over time. Budget for these ongoing costs:

Annual French drain inspection: Self-perform by running water through the system and checking discharge flow. Cost: $0 (DIY) or $150–$300 (professional camera inspection every 3–5 years)
Cleanout flushing: If cleanout access points were installed, flush with a garden hose annually. If not, plan for hydrojetting every 5–10 years: $300–$600
Inlet maintenance: Clear any debris from catch basins or inlet points after storms. Cost: $0 (15-minute task)
Slope vegetation management: Maintain ground cover on graded slopes; replant bare spots immediately. Budget $100–$300/year in materials

Think of drainage maintenance as you would changing the oil in your car—the preventive cost is trivial compared to the failure cost.

Your Seasonal Maintenance Calendar

Spreading maintenance tasks across the year prevents the "out of sight, out of mind" problem that causes most drainage systems to silently degrade. Here's a practical schedule to follow:

Early Spring (March–April): Walk the entire drainage path after the first heavy rain. Look for new pooling areas, erosion rills on slopes, and any surface settling that might indicate pipe movement or soil washout underneath. Clear winter debris from inlet grates and catch basins. This is also the time to reseed any bare spots on graded slopes before summer heat bakes the soil hard.
Late Spring (May): Flush cleanout access points with a garden hose for 5–10 minutes and observe the discharge end. Water should flow freely and clear within a few minutes. Sluggish or murky discharge suggests silt buildup—schedule a hydrojet flush before the wet season.
Summer (June–August): Monitor slope vegetation. Ground cover on graded areas should be dense enough that you can't easily see bare soil. Thin or patchy coverage is an early warning sign of erosion stress. Apply erosion control blanket or additional seed in August so roots establish before fall rains.
Fall (October–November): Leaf accumulation is the number-one cause of inlet blockages. Check and clear inlet points after leaf drop—this takes 15 minutes and prevents hours of saturated soil damage. Also inspect window wells and any area drains tied into the system.
After Any Major Storm: A storm delivering more than 2 inches of rain in 24 hours warrants a quick walkthrough. Look for new erosion channels, displaced gravel, or standing water persisting more than 24 hours after rain stops.

Recognizing Early Warning Signs of System Failure

Catching problems early is the difference between a $200 flush and a $4,000 system replacement. Watch for these red flags:

Standing water lasting more than 24–48 hours after a rain event suggests the drain is undersized, blocked, or that the outlet has become obstructed.
Soft or spongy ground along the drain path in dry weather indicates the pipe may have collapsed or that filter fabric has failed, allowing soil to migrate into the gravel.
Outlet running constantly even days after dry weather points to a high water table issue that may require a sump pump addition to the system.
Sinkholes or surface depressions near the drain trench are a serious sign—stop using the area, probe carefully, and call a professional. Pipe collapse under soil load can worsen quickly.

The True Long-Term Cost of Neglect vs. Maintenance

Running the numbers makes the case for consistent upkeep impossible to argue against. A homeowner who spends roughly $200–$400 per year on maintenance—inspection, flushing, vegetation management—will spend approximately $2,000–$4,000 over a decade. A neglected system that fails at year 7 or 8 requires full excavation and reinstallation: typically $5,000–$15,000, not counting any foundation or landscaping damage that accumulated while the system was underperforming.

Maintenance ROI rule of thumb: Every $1 spent on annual drainage maintenance prevents an estimated $8–$12 in reactive repair costs over a 10-year window—a return that rivals nearly any home improvement investment.

Keep a simple maintenance log—even a note in your phone's calendar app—with the date, what you checked, and what you found. This record becomes valuable documentation if you ever file a homeowner's insurance claim related to water damage, or if drainage condition becomes a point of negotiation during a home sale.

Key Takeaways and Quick Reference

Before you reach out to a contractor or head to the home improvement store, review these essential numbers:

Minimum grade away from foundation: 5% (6 inches per 10 feet)
Minimum French drain slope: 1% (1 inch per 8 feet)
Basic grading cost: $500–$5,000 depending on scope
French drain installed cost: $20–$40 per linear foot (exterior), $50–$100 (interior)
Erosion blanket cost: $0.15–$0.50 per sq ft installed
Average drainage project ROI (10-year horizon): 200–500%+
Foundation repair cost range: $2,500–$100,000 depending on severity

The Full-Picture Cost Benchmark Table

Use this reference table to quickly estimate where your project falls before entering detailed numbers into any calculator. These ranges reflect national averages; adjust upward by 15–25% for high cost-of-living metro areas (Northeast, Pacific Coast) and downward by 10–15% for rural Midwest and Southern markets.

Simple re-grading (under 1,000 sq ft): $500–$1,500
Moderate re-grading with soil amendment (1,000–5,000 sq ft): $1,500–$5,000
Full-yard grading with heavy equipment: $5,000–$15,000
French drain, exterior perimeter (100 linear feet): $2,000–$4,000
French drain, interior basement perimeter (100 linear feet): $5,000–$10,000
Catch basin installation (per basin): $300–$800
Dry creek bed or surface swale (per 50 linear feet): $500–$2,500
Hydroseeding after grading (per 1,000 sq ft): $150–$400
Riprap armoring (per 10 sq yd): $200–$600 installed
Sump pump system (interior): $1,000–$3,500 including installation

Decision Flowchart: Which Solution Do You Actually Need?

Not every wet yard needs a French drain, and not every drainage issue requires a contractor. Work through these questions in order to identify your most likely solution path:

Is water pooling within 10 feet of your foundation? If yes, start with re-grading before adding any drain system. Grading fixes the source; drains manage the symptom.
Does standing water persist more than 24–48 hours after rainfall? If yes, your soil's percolation rate is the limiting factor—consider a French drain or dry well to accelerate subsurface movement.
Is your property on a slope greater than 8%? If yes, erosion control is non-negotiable alongside any grading work. Budget at least $0.25 per square foot for temporary blankets or $1–$3 per square foot for permanent groundcover establishment.
Do you have basement seepage or interior moisture? If yes, exterior solutions should always be exhausted first—they cost less and address the root cause. Interior systems are a last resort when exterior access is impractical.
Is the affected area under 500 sq ft with less than 3 inches of re-grading required? If yes, this is realistic DIY territory. If the scope is larger, the cost of equipment rental and material waste typically eliminates the savings advantage.

The Four Numbers That Drive Every Drainage Decision

After everything covered in this guide, four figures do the most work when you're evaluating whether to act, what to install, and whether the investment makes sense:

$15,000 — The conservative average cost of moderate foundation repair. This is your baseline avoided-cost figure when calculating ROI on any drainage project.
6 inches — The minimum drop over the first 10 feet from your foundation. If your yard doesn't meet this benchmark, you have an active risk condition.
24 hours — The maximum time water should stand in your yard after a 1-inch rainfall event. Longer than this signals a drainage deficiency worth correcting.
3x — A conservative estimate of how much every dollar of deferred drainage maintenance can cost in eventual repair. A $200 annual maintenance habit can realistically prevent a $600+ repair bill.

Water problems don't get better on their own. Every season you delay a drainage fix is another season of hydrostatic pressure, soil movement, and moisture intrusion compounding the damage. The math consistently shows that drainage improvements are among the highest-ROI investments a homeowner can make—not because they add value, but because they prevent catastrophic value destruction.

Bottom line: A $3,000 drainage project that prevents a $20,000 foundation repair doesn't just pay for itself—it pays for itself six times over. The homeowners who regret drainage work are rare. The homeowners who regret waiting are common.

Ready to run the numbers on your specific situation? Visit unreliant.com to access our free Land Grading Cost Calculator, French Drain Sizing Tool, and Drainage ROI Calculator—three tools designed to help you make a confident, data-driven decision before you spend a single dollar on materials or labor.