Why Renovation Budgets Keep Blowing Up Mid-Project

What happened

According to Realtor.com, 43% of homeowners who recently hired a professional for a home project ended up spending more than their initial estimate, citing Angi's 2026 State of Home Spending Pulse. Of those who went over budget, more than a third spent at least 30% more than planned.

Realtor.com reports that the biggest driver usually isn't the cost of labor or materials on their own—it's what gets discovered once walls and floors are opened up. In older homes, that routinely means electrical panels at capacity, outdated galvanized plumbing, or subfloor damage that wasn't visible before work started. On top of that, a single "simple" change mid-project—like moving a kitchen island—can ripple across cabinetry, countertops, electrical, plumbing and flooring all at once, especially if materials have already been ordered.

Realtor.com also points to a gap between what a homeowner assumes is included in a quote and what the contractor actually scoped—painting touch-ups in the work area versus a whole-house repaint, for example. Material costs have risen too, driven by tariffs and inflation, though the piece is clear that price increases alone don't explain every added charge on a bill.

On the fix, Realtor.com reports that a fixed-price contract shifts the risk of estimating accurately onto the contractor, rather than the time-and-materials approach, which puts that risk on the homeowner. For houses built before 1985, the outlet cites advice to set aside a dedicated contingency fund for electrical, plumbing and structural surprises—separate from your finish budget—with a suggested range of $30,000 to $75,000 depending on the home's age, condition and location. As one quote in the piece puts it, "a contractor who lets scope keep expanding midproject is not doing you a favor."

What it means for your budget

That advice lines up with how costs actually break down on the ground. Here's roughly where the risk sits on the projects most likely to run into mid-project surprises.

Kitchens and bathrooms carry the most scope risk. These are the projects Realtor.com singles out, because moving even one fixture touches several trades at once. A typical kitchen remodel runs $9,350 – $15,600, with a mid-tier job landing around $12,000—but that's before a mid-project island resize or a cabinet change pulls in extra electrical and plumbing work. See the full Kitchen remodel for how the tiers break down. A bathroom remodel typically runs $10,600 – $17,600, around $13,600 for a mid-tier job; full details are in the Bathroom remodel.

Older homes should budget for what's behind the walls, not just the finish. If your house predates the mid-1980s and a project involves opening walls or floors, the panel, wiring or plumbing behind them is a real line item, not a hypothetical one. A full house rewiring typically runs $6,250 – $10,400, around $8,000, and that's the kind of cost that shows up as a change order if nobody priced it in up front. See the House rewiring for what drives that range.

Foundations and structure are where "discovery" costs bite hardest. A single foundation crack repair is a modest $500 typically, but a fuller foundation repair job runs $15,600 – $26,000, around $20,000—exactly the kind of structural finding Realtor.com describes surfacing once a project is underway. Check the Foundation repair before you rule it out of your contingency.

How we'd apply the advice

The practical takeaway from the Realtor.com piece is to separate two numbers before you sign anything: the price for the finish work you've actually selected, and a contingency for what might be found once the trades start opening things up. We build our own cost figures the same way—labor hours multiplied by local rates plus materials, checked against market prices and real quotes—so you can use our guides to sanity-check both halves of that budget rather than relying on a single contractor's number.

If you already have a quote in hand, it's worth running it past our "is my quote fair" tool before you commit, particularly if the price seems to assume no surprises at all. And if a contractor's scope document doesn't say what happens if they find bad wiring or a cracked foundation wall once demolition starts, that's the question to ask before work begins—not after the budget has already moved.