Home age in ZIP 37921, Knoxville, TN: median built 1978

Home age is not roof age, and the Census does not record replacements. ZIP 37921 in Knoxville, TN: median home built 1978; 78.7% of homes (10,205) are older than 25 years and 4.9% (634) were built since 2010, out of 12,969 homes.

U.S. Census Bureau, American Community Survey 2019 to 2023 (5-year estimates), retrieved October 9, 2026. Area = Census ZIP Code Tabulation Area 37921.

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Share of homes in ZIP 37921 by decade builtColumns from the pre-1940 decade on the left to 2020 and later on the right. pre-1940 8.6 percent; 1940s 8 percent; 1950s 12 percent; 1960s 8.9 percent; 1970s 14.9 percent; 1980s 12.5 percent; 1990s 13.8 percent; 2000s 16.4 percent; 2010s 3.8 percent; 2020+ 1.1 percentpre-1940: 1,120 homes, 8.6%8.6%pre-1940Knox County: 6.7%1940s: 1,032 homes, 8.0%8%1940sKnox County: 4.9%1950s: 1,557 homes, 12.0%12%1950sKnox County: 8.2%1960s: 1,150 homes, 8.9%8.9%1960sKnox County: 9.7%1970s: 1,927 homes, 14.9%14.9%1970sKnox County: 14.4%1980s: 1,623 homes, 12.5%12.5%1980sKnox County: 13.0%1990s: 1,796 homes, 13.8%13.8%1990sKnox County: 15.7%2000s: 2,130 homes, 16.4%16.4%2000sKnox County: 15.0%2010s: 497 homes, 3.8%3.8%2010sKnox County: 10.6%2020+: 137 homes, 1.1%1.1%2020+Knox County: 1.7%Built 1999 or earlier: 78.7% of homes (10,205)ZIP 37921, built before 2000built 2000 or laterKnox County

Share of the 12,969 housing units in the ZIP, by decade built. The red marks are Knox County. This counts houses, not roofs: a roof is replaced several times in the life of a house, and no federal survey records when.

ZIP 37921 next to Knoxville and Knox County

IndicatorZIP 37921KnoxvilleKnox CountyRank among 8 ZIPs of Knoxville on this site
Housing units12,96994,885214,6063rd of 8 largest
Median year built1978197419855th of 8 oldest
Built before 198052.3%59.4%44%
Built before 200078.7%no data72.7%5th of 8 highest share
Built since 20104.9%no data12.3%
Owner-occupied homes60.9%46.6%64.9%1st of 8 highest share
Single-family units75.8%57.4%no data
Median home value$204,300 (+/- $10,487)$214,000$279,7006th of 8 highest
Median household income$57,813 (+/- $6,543)$50,994no data3rd of 8 highest

City figures are for the Census place, county figures for the county; “no data” means the Census file does not publish that figure. Value and income are survey estimates, the plus-or-minus is the 90% margin of error.

Every decade in ZIP 37921

BuiltShare of Knox CountyShare of ZIPHomes in ZIP 37921
2020+1.7%1.1%137
2010s10.6%3.8%497
2000s15.0%16.4%2,130
1990s15.7%13.8%1,796
1980s13.0%12.5%1,623
1970s14.4%14.9%1,927
1960s9.7%8.9%1,150
1950s8.2%12.0%1,557
1940s4.9%8.0%1,032
pre-19406.7%8.6%1,120

Counts are Census estimates of housing units by year built (table B25034). If a roof had never been replaced, it would be 3 to 6 years old on a house from the 2020s, 17 to 26 on one from the 2000s, 37 to 46 on one from the 1980s and 87 or more on one from before 1940. Most older houses have had at least one replacement, and the Census does not record when.

What the numbers say about ZIP 37921

ZIP 37921 has 12,969 housing units: 10,205 (78.7%) were built before 2000, 634 (4.9%) in 2010 or later, and 2,130 (16.4%) in the 2000s, its largest era. The median year built is 1978 (Knoxville: 1974), so 4 years newer than the city.

Housing mix and money, from the same survey: 60.9% of occupied homes are owner-occupied; 75.8% of units are single-family houses; the median owner-occupied home is valued at $204,300, give or take $10,487; median household income is $57,813, give or take $6,543; the ZIP holds 13.7% of the housing units the Census counts in Knoxville, 12,969 of them. These are survey estimates with margins of error, and for a small ZIP the margin can be wide.

Reading this for roofs, carefully: the Census records when a house was built, never when its roof was last replaced. If every roof were still the one installed with its house, 8,409 units (64.8%, built before 1990) would be past the 30-year top of the usual asphalt-shingle range, 1,796 (13.8%, the 1990s) would mostly sit past it, 2,130 (16.4%, the 2000s) would mostly be inside the 20 to 30 year window and 634 (4.9%, 2010 onward) would be younger than it. Most older roofs have been replaced, so treat these as the pool of houses where an old roof is possible, not as a count of old roofs.

Roof age calculator for ZIP 37921

Enter the year your house was built, and the year the roof was last replaced if you know it. It starts at the median year built for this ZIP. The share of neighbours’ homes older than yours comes from this ZIP’s own decade counts.

–years old (roof)
–of homes in ZIP 37921 are older
–vs. the ZIP median year built

Material ranges are general planning figures (the same ones as on our roof-age page), not warranties. Sun, storms, attic ventilation and installation quality move them. The decade shares assume homes were built evenly within each decade. This is not an inspection: a roofer on the roof decides.

Map: ZIP 37921 among Knoxville’s ZIP areas

Map of ZIP 37921 and nearby ZIP areas, shaded by the share of homes built before 2000ZIP 37919: 15,499 homes, 82.3% built before 2000, median year 197737919ZIP 37917: 14,216 homes, 93.7% built before 2000, median year 194937917ZIP 37912: 10,916 homes, 80.9% built before 2000, median year 197937912ZIP 37909: 8,076 homes, 84.4% built before 2000, median year 198337909ZIP 37915: 3,722 homes, 65.2% built before 2000, median year 197737915ZIP 37916: 3,644 homes, 50.3% built before 2000, median year 200037916ZIP 37902: 1,908 homes, 69.8% built before 2000, median year 196837902ZIP 37921: 12,969 homes, 78.7% built before 2000, median year 197837921
  • under 20% built before 2000
  • 40 to 60%
  • 80% or more
  • Dot size = housing units. Red ring = ZIP 37921. Click a dot to open that ZIP.

Closest ZIP areas

ZIPMilesMedian builtPre-2000
379122.3 NE197980.9%
379092.4 SW198384.4%
379164.2 SE200050.3%
379194.4 S197782.3%
379024.7 E196869.8%
379175.2 E194993.7%

Distance is between Census ZIP centres.

Storm backdrop: Knox County

A ZIP is too small for its own hail record, so this is the county. FEMA’s National Risk Index rates Knox County Relatively Moderate overall (92.1 of 100), Relatively Low for hail (59.7), Relatively High for strong wind (89.3) and Relatively High for tornado (96.7). NOAA logged 48 hail reports in the county, on 22 days with hail of 1 inch or more in the full years 2014 to 2025.

FEMA National Risk Index, December 2025 version, county level. This product uses FEMA’s National Risk Index data but is not endorsed by FEMA.

Where to go from here

Other roofing cities near ZIP 37921: Cookeville, TN (85 miles), Asheville, NC (86 miles), Kingsport, TN (89 miles).

Questions

How old are the homes in ZIP 37921?

Of the 12,969 housing units, 6,786 (52.3%) were built before 1980, 10,205 (78.7%) before 2000 and 634 (4.9%) from 2010 on (Census ACS 2019 to 2023, survey estimate).

Does a house's age tell me how old its roof is in 37921?

No. ACS records the year the structure was built, not the year the roof was last replaced. With 6,786 units built before 1980 in this ZIP, many roofs are replacements rather than originals. Ask the seller for permit records or have a roofer inspect the roof.

Which nearby ZIP has the oldest housing?

Of the 6 closest ZIP areas we cover, 37917 (5.2 miles E) has the largest share built before 2000, 93.7%, against 78.7% in 37921.

Source: U.S. Census Bureau, American Community Survey 5-year estimates 2019 to 2023, tables B25034 (year structure built), B25035, B25003, B25024, B25077 and B19013, ZIP Code Tabulation Areas; ZIP-to-city assignment from the Census 2020 ZCTA-to-place relationship file (a ZIP is assigned to a city when more than half of its land area lies inside it). A ZCTA is not a USPS ZIP code: it approximates one and can differ at the edges. Public domain. The 12 ZIP-specific figures above differ from ZIP to ZIP.

Information only, not a roof inspection. Pickaroofer does not know the condition of any individual roof.