I’ve walked through a lot of houses. And I mean a lot.
There’s a feeling you get when you walk into a place that has potential — you start mentally painting walls, imagining the after photos, running ARV numbers in your head. It’s exciting. And that excitement is exactly what gets people into trouble.
Because while you’re picturing the finished product, there are things hiding behind the walls, under the floors, and in that electrical panel outside that can quietly blow your budget before demo even starts.
I watched a video recently where an investor laid out a solid flip — $350k purchase, $60k rehab, targeting $550k ARV. The plan was tight: add a bedroom, open up the kitchen, retile the bathrooms. Clean, focused scope. And at the end, almost as an afterthought, he mentioned one thing — always check the electrical panel before you buy.
That one tip stuck with me. Because it’s the kind of thing that sounds obvious until you’re $15k into a flip and your contractor tells you the panel needs to be upgraded before he can touch anything else.
So I built a checklist. One I wish I’d had when I was walking properties and trying to hold all these numbers in my head at once.
The stuff that kills your margins
There are cosmetic problems and there are structural problems. Cosmetic problems are fine — that’s literally what you’re there to fix. Structural problems are what you need to price in before you make an offer.
Here’s what I look at every single time:
Electrical panel — This is the one from the video and it’s real. Older homes especially. If the panel is outdated or undersized for the renovation you’re planning, you’re looking at $1,500 to $4,000 to upgrade it. Not optional.
Roof — Walk around the outside and look up. Check the attic if you can. A full roof replacement can run $8,000 to $15,000 depending on size and material. A bad roof that shows up in inspection can kill your deal or crater your offer price.
HVAC — How old is the system? If it’s original to a 1970s house, budget for replacement. $5,000 to $12,000 depending on the system and size of the home.
Plumbing — Old galvanized pipes, cast iron that’s deteriorating, signs of water damage on ceilings or under sinks. Any of these can snowball fast. $3,000 to $8,000 for significant plumbing work, more if you’re opening walls.
Foundation — Cracks in the basement walls, uneven floors, doors that don’t close right. This is the one that scares me most because it’s the hardest to price without a specialist.
Windows — Easy to overlook but adds up fast if you’re replacing them all. $300 to $800 per window installed.
Water heater — How old is it? If it’s over 10 years, budget for replacement. $800 to $1,500.
Why I built the calculator below
I got tired of trying to do this math in my head while walking a property. Or worse, doing it later on a spreadsheet when the adrenaline had already made me half-committed to the deal.
Now I pull it up on my phone, check off what I see, and by the time I walk out the door I have a rough rehab number staring back at me.
It’s not a substitute for a contractor walkthrough. But it’s enough to know whether a deal is worth pursuing before you spend time and money on due diligence.
Run the numbers before you run the emotions.