Annual Residential Roof Age Index Report: Knoxville & East Tennessee
How old are residential roofs in East Tennessee and where do older roofs meet frequent hail?
- Published September 2026
An estimated 99,000 owner-occupied single-family homes in the Knoxville area have a roof that is 20 years old or older: an estimated 39% of homes, with an estimated range of 31% to 48%. Replacing those roofs at the regional median cost of a roof job would total an estimated $880 million. The study covers Anderson, Blount, Campbell, Grainger, Knox, Loudon, Morgan, Roane, Sevier and Union counties (the Knoxville metropolitan area plus Sevier County). Every roof-age figure on this page is shown with its estimated range. How the estimates are made.
Key findings
- Knox County accounts for nearly half the total, with an estimated 46,000 homes with an older roof (39%, range 32–48%) and $410 million in replacement value.
- Of the three markets studied, the Knoxville area is the only one where an older roof stock and above-average hail coincide. 63% of its homes are in counties rated Highest or Elevated on the Composite Risk Index.
- Hail is more frequent than the three-market average. NOAA radar detected hail 1 inch or larger 1.4 days a year at a typical location, about 8% above average. Anderson and Roane counties each averaged 1.8 days.
- Replacement values use the East Tennessee regional median roof-job cost of $8,900 (2023), lower than the $11,000 used for the Carolinas.
- Climate: 35 days a year at 90°F or hotter and 79 freeze-thaw days (NOAA normals, 1991–2020).
Estimated roof age by county
County | Rank | Estimated share of homes with a roof 20+ years old | Estimated range | Estimated median roof age | Estimated homes with a roof 20+ years old | Estimated replacement value |
|---|---|---|---|---|---|---|
Anderson County, TN | 1 | 42% | 32–52% | 13–21 years | 8,700 | $77 million |
Roane County, TN | 2 | 42% | 32–51% | 13–20 years | 6,400 | $57 million |
Campbell County, TN | 3 | 40% | 31–49% | 13–20 years | 4,000 | $35 million |
Knox County, TN | 4 | 39% | 32–48% | 13–19 years | 46,000 | $410 million |
Morgan County, TN | 5 | 38% | 30–47% | 13–18 years | 1,700 | $15 million |
Blount County, TN | 6 | 38% | 31–47% | 13–19 years | 14,000 | $130 million |
Union County, TN | 7 | 38% | 31–46% | 13–19 years | 1,900 | $17 million |
Grainger County, TN | 8 | 37% | 30–46% | 12–18 years | 2,000 | $18 million |
Sevier County, TN | 9 | 37% | 30–45% | 12–18 years | 8,500 | $75 million |
Loudon County, TN | 10 | 35% | 29–43% | 12–17 years | 6,100 | $54 million |
Estimates from the Benton Roofing Roof Age Index, modeled from U.S. Census Bureau American Community Survey 2020–2024 and American Housing Survey 2017–2023 data. Owner-occupied single-family detached homes, as of 2026. Estimates, not measurements; ranges combine survey uncertainty and model choice. Replacement values use the regional median roof-job cost and are conservative.
Twenty years is the life expectancy that a 2007 National Association of Home Builders and Bank of America Home Equity study lists for asphalt roofing. Actual roof life varies, and an older roof doesn’t necessarily need replacing.
ZIP codes
ZIP estimates apply the same regional replacement rate as the county figures, so differences of a few points between ZIP codes fall within their estimated ranges. ZIP codes with fewer than 50 qualifying homes are withheld. Every ZIP code is in the downloadable data.
ZIP codes with the most homes with an older roof
ZIP code | Rank | County | Estimated homes with a roof 20+ years old | Estimated replacement value | Estimated share of homes with a roof 20+ years old | Estimated range |
|---|---|---|---|---|---|---|
37918 | 1 | Knox County, TN | 4,700 | $42 million | 41% | 34–51% |
37922 | 2 | Knox County, TN | 4,300 | $38 million | 36% | 29–44% |
37920 | 3 | Knox County, TN | 4,100 | $37 million | 42% | 32–52% |
37803 | 4 | Blount County, TN | 4,100 | $36 million | 39% | 32–48% |
37830 | 5 | Anderson County, TN | 3,800 | $34 million | 44% | 32–53% |
37934 | 6 | Knox County, TN | 3,300 | $29 million | 38% | 30–47% |
37876 | 7 | Sevier County, TN | 3,000 | $27 million | 35% | 29–43% |
37716 | 8 | Anderson County, TN | 3,000 | $26 million | 42% | 32–51% |
37919 | 9 | Knox County, TN | 2,900 | $26 million | 42% | 30–51% |
37849 | 10 | Knox County, TN | 2,900 | $26 million | 39% | 32–48% |
ZIP codes with the highest share of older roofs
Among ZIP codes with at least 500 qualifying homes.
ZIP code | Rank | County | Estimated share of homes with a roof 20+ years old | Estimated range | Estimated homes with a roof 20+ years old |
|---|---|---|---|---|---|
37828 | 1 | Anderson County, TN | 45% | 34–56% | 250 |
37917 | 2 | Knox County, TN | 45% | 32–56% | 2,500 |
37762 | 3 | Campbell County, TN | 45% | 32–55% | 300 |
37853 | 4 | Blount County, TN | 44% | 33–55% | 320 |
37830 | 5 | Anderson County, TN | 44% | 32–53% | 3,800 |
37923 | 6 | Knox County, TN | 43% | 32–53% | 2,700 |
37748 | 7 | Roane County, TN | 43% | 33–53% | 2,000 |
37914 | 8 | Knox County, TN | 43% | 33–53% | 2,300 |
37863 | 9 | Sevier County, TN | 43% | 33–53% | 390 |
37887 | 10 | Morgan County, TN | 43% | 30–53% | 510 |
Estimates from the Benton Roofing Roof Age Index, modeled from U.S. Census Bureau American Community Survey 2020–2024 and American Housing Survey 2017–2023 data. Owner-occupied single-family detached homes, as of 2026. Estimates, not measurements; ranges combine survey uncertainty and model choice. Replacement values use the regional median roof-job cost and are conservative.
How often hail hits
Rank | County | Radar hail days/yr (1 in+) | Radar hail days/yr (1.75 in+) | Hail Exposure Index |
|---|---|---|---|---|
1 | Anderson County | 1.8 | 0.36 | 139 |
2 | Roane County | 1.8 | 0.39 | 137 |
3 | Morgan County | 1.8 | 0.31 | 133 |
4 | Loudon County | 1.6 | 0.35 | 124 |
5 | Knox County | 1.5 | 0.36 | 116 |
6 | Campbell County | 1.4 | 0.25 | 104 |
7 | Blount County | 1.2 | 0.31 | 94 |
8 | Sevier County | 1.2 | 0.24 | 90 |
9 | Grainger County | 0.9 | 0.12 | 66 |
10 | Union County | 0.8 | 0.15 | 60 |
Sources: NOAA NCEI Severe Weather Data Inventory (NEXRAD Level-III hail detections) and NOAA NCEI Storm Events Database, 2000–2025. Radar hail days = average days a year radar detected hail 1 inch or larger at a typical location in the county. Index: three-market average = 100.
Where older roofs meet frequent hail
The Composite Risk Index ranks all 44 counties in the study on both estimated roof age and radar hail frequency, then retests every ranking under 12 sets of assumptions. Tiers compare the study’s counties with each other and are not a forecast of damage.
Anderson and Roane counties are rated Highest, each in 8 of the 12 assumption sets tested. Campbell and Knox counties are rated Elevated, in 9 and 7 of 12. Knox County’s rating is medium confidence. Blount, Loudon, Morgan and Sevier counties did not hold a consistent rating and are not assigned a tier.
County | Tier | Assumption sets agreeing | Estimated share of homes with a roof 20+ years old | Radar hail days a year | Days at 90°F or hotter (context) | Freeze-thaw days (context) |
|---|---|---|---|---|---|---|
Anderson County, TN | Highest | 8 of 12 | 42% | 1.8 | 39 | 70 |
Roane County, TN | Highest | 8 of 12 | 42% | 1.8 | 35 | 80 |
Campbell County, TN | Elevated | 9 of 12 | 40% | 1.4 | 25 | 99 |
Knox County, TN | Elevated | 7 of 12 | 39% | 1.5 | 36 | 82 |
Grainger County, TN | Lower | 7 of 12 | 37% | 0.9 | 17 | 57 |
Union County, TN | Lower | 7 of 12 | 38% | 0.8 | 17 | 93 |
Blount County, TN | No consistent tier | — | 38% | 1.2 | 37 | 62 |
Morgan County, TN | No consistent tier | — | 38% | 1.8 | 14 | 97 |
Sevier County, TN | No consistent tier | — | 37% | 1.2 | 32 | 89 |
Loudon County, TN | No consistent tier | — | 35% | 1.6 | 43 | 72 |
Composite Risk Index, Benton Roofing Roof Age Index. Tiers combine where roofs are oldest (estimated share of owner-occupied single-family homes with a roof 20+ years old) and where hail is most frequent (NOAA radar hail days, 2000–2025), ranked in thirds across the 44 counties in Benton Roofing’s three markets. Each county was tested under 12 sets of assumptions; the tier shown is the one it lands in most often, with how many of the 12 agree. Counties without a consistent result are not assigned a tier. Tiers are relative to these 44 counties, not a forecast of damage. Heat and freeze-thaw days (NOAA 1991–2020 normals) are shown for context and are not part of the tier.
Heat and freeze-thaw
County | Days a year at 90°F or hotter | Freeze-thaw days a year | NOAA stations used |
|---|---|---|---|
Alleghany County, NC | 12 | 97 | 1 station |
Ashe County, NC | 1 | 123 | 2 stations |
Avery County, NC | less than 1 | 107 | 1 station |
Buncombe County, NC | 7 | 97 | 8 stations |
Burke County, NC | 35 | 88 | 1 station |
Caldwell County, NC | 36 | 88 | 1 station |
Cherokee County, NC | 21 | 100 | 2 stations |
Clay County, NC | 3 | 100 | 1 station |
Graham County, NC | 8 | 87 | 1 station |
Haywood County, NC | 2 | 119 | 2 stations |
Henderson County, NC | 10 | 91 | 3 stations |
Jackson County, NC | 13 | 98 | 1 station |
Macon County, NC | 9 | 102 | 2 stations |
Madison County, NC | 13 | 114 | 1 station |
McDowell County, NC | 21 | 102 | 2 stations |
Mitchell County, NC | 2 | 115 | 1 station, nearby county |
Polk County, NC | 33 | 49 | 1 station |
Rutherford County, NC | 45 | 89 | 2 stations |
Swain County, NC | 8 | 105 | 2 stations |
Transylvania County, NC | 7 | 111 | 2 stations |
Watauga County, NC | less than 1 | 102 | 2 stations |
Wilkes County, NC | 32 | 98 | 2 stations |
Yancey County, NC | 2 | 98 | 2 stations |
Source: NOAA NCEI U.S. Climate Normals 1991–2020. County figures are the median of NOAA stations in the county within 200 m of the elevation where most residents live, or the nearest representative station where a county has none. Local microclimates vary; single-station counties are less certain. Freeze-thaw days: the low reaches 32°F or colder and the high rises above 32°F. A descriptive climate comparison, not an estimate of roof life. Benton Roofing Roof Age Index.
If you own a home here
An older roof doesn’t necessarily need to be replaced. Roof life depends on the material, how it was installed, how it has been maintained and the weather it has faced. This study describes the age of the housing stock, not the condition of any one roof.
If you don’t know how old your roof is, the paperwork from your home purchase, a past inspection report, a building permit record or the installer’s warranty may tell you. A roof inspection can tell you its condition.
Use and cite this data
The data, tables and charts are free to download and reuse under the Creative Commons Attribution 4.0 International License (CC BY 4.0), including for commercial use. Please credit Benton Roofing, Roof Age Index 2026, link to https://bentonroofing.com/roof-age-index/, and note any changes you made. The Benton Roofing name and logo are not covered by the license.
Found an error? Email contact@bentonroofinginc.com. Corrections are noted on the methodology page with their date.