How do I estimate repairs if I can't get inside the property?

Scope from what you can verify: roof condition from the street or satellite view, HVAC age from the outdoor unit's data plate, era of finishes from old listing photos, and square footage from county records. Then assume one tier worse than what you can see and protect yourself with an inspection contingency.

How much contingency should a rehab budget carry?

Add 10–15% on a walkable, visually clear project and 20% or more on older homes or anything scoped from the curb. Houses built before 1980 hide the expensive surprises — wiring, plumbing, sewer lines — inside the walls.

What are the biggest budget killers in a rehab?

Foundation movement, full re-plumbs and rewires, sewer line replacement, and structural roof repairs. None of them add a dollar of resale value — they just make the house sellable — which is why one missed system item can erase an entire flip profit.

Should I just get contractor quotes instead of estimating myself?

Quotes come after the contract, not before the offer. You'll analyze dozens of leads for every deal you sign — no contractor will walk 30 maybes, and waiting for quotes means losing deals to faster buyers. Estimate to offer; quote to execute.

How to Estimate Rehab Costs Without a Contractor

You don’t need a contractor’s license to estimate a rehab — you need a repeatable system and honest inputs. Wholesalers especially: your repair number gets audited by every cash buyer who looks at the deal, and a number that’s $25,000 light marks you as an amateur. Here’s the system.

Start with the tier, not the line items

Ninety percent of houses fall cleanly into one of three buckets. Price the bucket first:

Light / cosmetic — roughly $15–$30 per square foot. Paint, flooring, fixtures, hardware, landscaping. The house’s systems and layout are fine; it just looks dated.
Medium — roughly $35–$60 per square foot. Everything in light, plus a kitchen and bath refresh, some drywall, maybe a roof or HVAC replacement. The classic “1990s house nobody updated.”
Full gut — $80+ per square foot. Down-to-studs work: layout changes, all-new systems, windows, everything. Fire jobs, long-vacant houses, hoarder houses.

A 1,400 sqft medium rehab pencils at roughly $49,000–$84,000. That’s a wide band — which is the point. The tier gets you in the neighborhood in 60 seconds; the line items below tighten it. And critically: these are ballpark national figures. A gut in rural Alabama and a gut in San Diego are different numbers. Calibrate the tiers once with a local contractor or an experienced local flipper, then reuse them forever.

The 12 categories that drive every budget

Walk (or virtually walk) the property against this list, marking each category none / minor / moderate / full replace:

Roof — replacement commonly $8,000–$15,000 on a typical single-family
HVAC — full system $6,000–$12,000
Kitchen — refresh $8,000–$15,000; full remodel $15,000–$30,000
Bathrooms — $4,000–$12,000 each depending on depth
Flooring — LVP commonly $4–$8 per sqft installed
Interior paint — $2–$4 per sqft of floor area
Windows — $400–$800 per opening
Electrical — panel swap $2,000–$4,000; full rewire $8,000–$15,000
Plumbing — repairs vs re-pipe $5,000–$15,000; sewer line $5,000–$15,000
Foundation / structure — the wildcard: $5,000 to $30,000+; always bid before closing
Exterior — siding, gutters, doors, landscaping
Demo, dumpsters, permits, cleanup — the forgotten $3,000–$8,000

The expensive lesson hiding in that list: systems eat budgets, finishes don’t. Buyers see the quartz counters; the money disappeared into the sewer line. When you’re rushed, check roof, HVAC, electrical, plumbing, and foundation first — the five that can each swing five figures.

This category-by-scope walkthrough is literally how PropTitan’s rehab estimator is built: pick a scope level for each of the 12 categories, and it generates the line-item budget from pre-seeded costs you can override with your local numbers — attached to the same screen running your comps and offer math. See the deal analysis feature for the full workflow.

Scoping when you can’t get inside

Most wholesale leads get scoped before access. Work the verifiable evidence:

County records give year built, square footage, and system permit history (a 2019 roof permit is a roof you don’t pay for).
Old listing photos on Zillow or Redfin show the interior’s era — a 2004 listing with oak cabinets that never re-listed means those cabinets are still there.
The street view shows roof, siding, windows, and yard — and neglect outside predicts neglect inside.
The seller’s own words: “When did you last update the kitchen? How old is the AC?” Sellers answer these honestly more often than they answer price questions.

Then apply the curb-scoping rule: assume one tier worse than what you can see, and let your inspection contingency be the safety net.

Contingency is not optional

Add 10–15% to any walkable project and 20%+ to pre-1980 houses or curb-scoped deals. In 50-plus-year-old housing stock, the wiring, plumbing, and sewer aren’t risks — they’re scheduled surprises. A budget with no contingency isn’t optimistic; it’s fictional.

Tie it back to the offer

The repair estimate exists to feed one number: your maximum offer. MAO = 70% of ARV minus repairs, so every dollar of missed scope is a dollar of overpayment — a $20,000 miss on repairs is a $20,000 miss on the offer. Run the full calculation in the free MAO calculator, and when a seller balks at your price, the itemized scope becomes your negotiation exhibit: “Here’s the $52,000 the next owner has to spend. That’s not my opinion — it’s the roof’s.”

Estimate in tiers, verify the big five systems, pad honestly, and put the number in writing. Buyers can forgive a repair estimate that’s $5,000 off. They remember the wholesaler whose estimates they can trust.