"Add 10-20% for contingency" is the most repeated piece of remodeling budget advice online, and it's not wrong — but it's incomplete. The real question isn't what percentage to set aside, it's what that money actually tends to get spent on, so you can budget with your eyes open instead of just padding a number and hoping.
Where contingency money actually goes on real projects
| Source | Frequency | Typical cost impact |
|---|---|---|
| Outdated wiring found behind walls | Common in homes 25+ years old | $800 – $3,500 |
| Subfloor damage from old leaks | Occasional, mostly bathrooms | $500 – $2,500 |
| Mid-project selection upgrades | Very common | Varies widely — this is the biggest one |
| Plumbing not up to current code | Common in homes with original 1970s–90s plumbing | $1,000 – $4,000 |
The line item that isn't in the "surprise" category at all
The single biggest driver of going over an initial budget on the projects we build isn't hidden structural problems — it's homeowners upgrading their own selections mid-project. Seeing an actual slab in person after budgeting for a lower tier, or falling in love with a tile that costs more than the allowance, happens on the majority of full remodels. That's not a failure of planning; it's a normal part of the process, and it's worth budgeting for honestly rather than being surprised by it.
A more useful contingency framework
For homes built after 2000 with no known plumbing or electrical issues: 10% contingency is usually adequate.
For homes built before 1995, or any home where walls haven't been opened in decades: 15–20% is more realistic, specifically because of the wiring and plumbing findings above.
For projects involving any wall removal or layout change: 15% minimum, since structural surprises are more likely once you're opening up framing.
How to actually protect your budget
- Finalize selections before demo, not during — this alone prevents the most common overage source
- Ask your contractor for a fixed-price proposal, not a rough estimate, so "contingency" covers genuine surprises rather than pricing gaps
- Set your contingency aside in a separate line you don't touch unless something specific triggers it — treating it as "extra budget for upgrades" defeats the purpose
- Ask what's included in your quote's demo phase specifically — whether wall opening for inspection is included, or billed separately if something's found
Every proposal we write is itemized and fixed-price specifically so you know what "contingency" is actually protecting against for your project, not a vague percentage tacked onto a rough number.