I looked at a bungalow in Beaverdale last spring that looked like a $20,000 cosmetic job from the listing photos. New paint, refinish the floors, update two bathrooms, done. The seller’s agent called it “move-in ready with a little TLC.” It wasn’t. Once I pulled back a section of drywall in the basement, I found knob-and-tube wiring behind it. That’s the difference between guessing at a number and learning how to estimate rehab costs before you make an offer. Guess wrong and you’re bidding on a number that isn’t real. Get it right and you know your true purchase price before you ever call the seller back.
How to Estimate Rehab Costs Before You Make an Offer
Estimating rehab costs before an offer means walking the property, pricing the work room by room, and building in a contingency, all before you land on a number to bring to the seller. Skip this step and you’re not underwriting a deal. You’re hoping.
Most first and second flips go sideways here. Not on the purchase price. On the gap between what the investor thought the rehab would cost and what it actually cost once the crew started tearing into walls.
Start With a Room-by-Room Walkthrough, Not a Guess
Before I write an offer, I walk every room with a notepad, not a phone calculator app open in the truck afterward. I’m looking at four things in every room:
- Cosmetic scope: paint, flooring, fixtures, trim
- Mechanical age: furnace, water heater, panel, main stack
- Structural signals: sloped floors, cracked foundation walls, water staining
- Anything hidden: outlets that don’t work, a smell in the basement, a panel that’s been “updated” with tape
That last category is where deals get expensive. You can’t fully price what’s behind the walls until you’re inside them, but you can price the risk. If a house has three or more of those hidden-cost signals, I add a heavier contingency before I ever run comps.
Build a Line-Item Scope Before You Bid
A line-item scope is a room-by-room, trade-by-trade list of every cost in the rehab, priced individually instead of lumped into one round number. “$30,000 for rehab” isn’t a scope. It’s a guess wearing a dollar sign.
Here’s the order I price things in:
- Mechanicals first: HVAC, electrical panel, plumbing, roof. These are the line items that surprise people, and they don’t move much regardless of finish level.
- Structural and envelope: foundation, framing repairs, windows, siding.
- Interior finishes: flooring, paint, trim, cabinets, countertops.
- Curb and exterior: landscaping, driveway, exterior paint or siding repair.
Pricing mechanicals first matters because they’re the items that can quietly double a budget. A cosmetic flip with a bad furnace and a 60-amp panel isn’t a cosmetic flip anymore.
Where Iowa Rehab Costs Actually Run
Numbers vary by neighborhood, crew, and house age, but here’s roughly what I see across Des Moines metro flips right now. A light cosmetic refresh, paint, flooring, fixtures, on a house that’s structurally sound, tends to run in the $15 to $25 per square foot range. A full gut, new mechanicals, new kitchen, new baths, on an older home in a neighborhood like Beaverdale or an established Ankeny pocket, can run $45 to $65 per square foot once you account for the age of the housing stock.
That range is wide on purpose. The house built in 1995 in Waukee and the house built in 1948 in Beaverdale are not the same rehab, even if the square footage matches. Use your own crew’s real numbers once you have them. Until then, price conservatively and let the line-item scope, not a rule of thumb, drive the offer.
Build In a Contingency Before You Ever Submit an Offer
Every rehab budget needs a contingency line, and it needs to be a real number, not an afterthought. On a light cosmetic project with no hidden-cost signals, 10 percent is usually enough. On an older home with any of the red flags from the walkthrough, I move that to 15 to 20 percent before I ever run the 70% rule.
The 70% rule is a fix-and-flip guideline that says an investor should pay no more than 70% of a property’s after-repair value, minus the rehab cost. On a house with a $280,000 ARV and a $55,000 rehab budget, including contingency, that puts the maximum purchase price around $141,000. If your rehab number is soft, your maximum offer is soft too. That’s why the estimate has to come before the offer, not after.
Loan Terms to Know Before You Bid
Once you have a real rehab number, it’s worth knowing how that number gets funded before you’re negotiating with a seller. Little Guy Loans finances Iowa fix-and-flip deals up to 90% of the purchase price and up to 100% of rehab costs, with a maximum of 70% of ARV as the controlling limit on any loan. That ARV cap is what governs the deal, not the purchase price or rehab number alone, which is exactly why the accuracy of your rehab estimate matters this much before you write an offer.
FAQ
How do I estimate rehab costs before I make an offer?
A rehab cost estimate is a line-item, trade-by-trade budget that prices mechanicals, structural work, and interior finishes separately, then adds a contingency of 10 to 20 percent depending on the property’s condition, before that total is used to calculate a maximum offer price.
What is the 70% rule in fix and flip investing?
The 70% rule is a fix-and-flip guideline that says an investor should pay no more than 70% of a property’s after-repair value, minus the total rehab cost. It’s the formula that turns a rehab estimate into a maximum purchase price.
How much contingency should I add to a rehab budget?
A contingency is the extra percentage added to a rehab budget to cover costs that surface once work begins. Ten percent is a reasonable floor for a light cosmetic project, and 15 to 20 percent is more realistic for an older home with any hidden-cost signals during the walkthrough.
What rehab costs surprise Iowa investors most often?
Mechanical and structural items, an aging furnace, an outdated electrical panel, or foundation movement, surprise investors most often, because they’re the hardest to fully assess from a walkthrough and the most expensive to fix once a crew is already on site.
The investors who protect their margin aren’t the ones who get lucky on the purchase price. They’re the ones who priced the rehab line by line before they ever wrote the offer. Walk the property with a notepad, not a guess. Price mechanicals first. Build in a real contingency. Then let the 70% rule tell you what the house is actually worth to you. Do that consistently, on every deal, and the rehab number stops being the part of the flip that keeps you up at night.
