Rob Hartley
Founder, AppealDesk · February 16, 2026
Property Tax Appeal After Home Renovation
Updated February 2026 · 9 min read
Renovations often trigger assessment increases, but counties frequently overestimate the added value. A $50,000 kitchen remodel doesn’t add $50,000 to your home’s market value — the National Association of Realtors reports most renovations recoup only 50-80% of their cost at resale. If your county increased your assessment by the full renovation cost, you likely have grounds to challenge it.
How Renovations Trigger Reassessment
When you pull a building permit, that record is typically shared with your county assessor’s office. The assessor reviews the permit to determine if the work adds value to your property. Improvements that change the property’s physical characteristics — square footage, room count, building quality — usually trigger an increase in assessed value.
The reassessment may happen immediately after the permit is closed, during the next regular reassessment cycle, or retroactively. The timing varies by county, but the increase is coming eventually if the permit exists.
Renovations That Typically Increase Assessment vs. Those That Don’t
Likely to Increase Assessment
- ↑ Adding square footage (additions, finished basements)
- ↑ Adding bedrooms or bathrooms
- ↑ Building a garage, deck, or pool
- ↑ Major kitchen or bathroom gut renovation
- ↑ Converting attic/garage to living space
- ↑ Adding central HVAC where none existed
Usually No Assessment Change
- → Replacing a roof with same material
- → Repainting interior and exterior
- → Replacing worn flooring with similar quality
- → Fixing plumbing leaks and electrical issues
- → Foundation repairs
- → Replacing HVAC with equivalent system
The key distinction is improvement vs. maintenance. Replacing a broken furnace with an equivalent model is maintenance. Installing a new furnace plus central air where there was none is improvement. Assessors should only increase value for improvements, not maintenance — but in practice, they sometimes conflate the two.
When a Post-Renovation Appeal Makes Sense
You should consider challenging your assessment after a renovation if:
- The increase exceeds the renovation’s market value contribution. Most renovations add less to market value than they cost. The NAR’s Remodeling Impact Report shows cost-to-value ratios of 50-80% for most projects. If your county added the full permit cost to your assessment, the increase is likely too high.
- The assessor inflated the scope of work. A permit for a bathroom remodel might trigger a reassessment of your entire home, not just the bathroom. Compare your pre- and post-renovation assessed values to see if the increase is proportional to the actual work.
- Maintenance was treated as improvement. If you replaced a roof, repaired foundation, or updated plumbing to maintain habitability, and your assessment increased, the assessor may have incorrectly categorized the work.
- Comparable sales don’t support the new value. Regardless of what you spent, your assessed value should reflect market value. If renovated homes similar to yours sell for less than your new assessed value, you have grounds to challenge it.
Check Your Post-Renovation Assessment
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Building Your Appeal Case After a Renovation
A post-renovation appeal requires slightly different evidence than a standard overassessment appeal:
- Comparable sales of renovated homes: Find 3-5 homes with similar renovations that sold recently. These establish what your type of renovation actually adds to market value. See our guide on finding comparable sales.
- Before/after documentation: Photos of your property before and after renovation. This helps the review board understand exactly what changed.
- Itemized cost breakdown: A detailed list of what you spent, separating structural improvements from maintenance/cosmetic work. The assessor should only count the improvement portion.
- Cost-to-value data: Reference industry data showing the typical return on your type of renovation. A $60,000 kitchen remodel that adds $40,000 in market value should increase your assessed value by approximately $40,000, not $60,000.
- Pre-renovation comparable assessment: Your assessed value before the renovation establishes the baseline. The increase should be reasonable relative to the actual value added, not the money spent.
Assessment Impact by Renovation Type
| Renovation | Typical Cost | Value Recouped | Reasonable Assessment Increase |
|---|---|---|---|
| Kitchen remodel (major) | $40,000-80,000 | ~60% | $24,000-48,000 |
| Bathroom remodel | $15,000-35,000 | ~60% | $9,000-21,000 |
| Room addition | $50,000-100,000+ | ~50-65% | $25,000-65,000 |
| Finished basement | $30,000-75,000 | ~50-70% | $15,000-52,500 |
| Deck or patio | $10,000-30,000 | ~65-75% | $6,500-22,500 |
| New roof (replacement) | $8,000-20,000 | Maintenance* | $0 (if same material/quality) |
*Like-for-like replacements are maintenance, not improvement, and should not increase assessed value. Cost-vs-value data sourced from Zonda’s Cost vs. Value Report and the NAR Remodeling Impact Report.
Timing Your Renovation and Appeal
Assessment timing varies by county. Some key patterns:
- Permits closed late in the year may not be reflected until the following year’s assessment. This gives you time to prepare your appeal evidence before the new value hits.
- Check your appeal deadline immediately after receiving a new assessment notice. In many states, you have only 30-60 days to file.
- In triennial reassessment counties (like Cook County, IL), permitted improvements may be added between reassessment cycles, giving the increase extra years before the next full reassessment.
See Your Estimated Overassessment
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