Home › Case Study
Case Study: How Old Are Johnson County’s Chimneys?
Johnson County has 259,655 homes with a median construction year of 1989, and 36.1 percent of them were built before 1980. Olathe is younger, with a median of 1994. Age matters because the decade a house was built is a strong hint about what kind of chimney it has and what tends to go wrong with it.
Call (913) 210-6606Last updated October 3, 2026
What question does this case study answer?
It answers how old the housing in our service area is, and what that age implies for chimney work. We took the count of homes by decade built for Johnson County and for Olathe, where our office is, and compared the two.
How old are homes in Johnson County?
The county has 259,655 housing units and a median construction year of 1989. 93,791 of them, or 36.1 percent, were built before 1980, and 68.7 percent were built before 2000. The three busiest decades were the 1980s, 1990s and 2000s, which together produced 128,421 homes, 49.5 percent of the total.
Johnson County: share of homes by decade built
How does Olathe compare with the county?
Olathe is newer. It has 54,594 housing units and a median construction year of 1994. Only 24.5 percent of Olathe homes predate 1980, against 36.1 percent countywide. The older share of the county sits mostly in the northeast, in towns such as Prairie Village, Mission, Roeland Park and Fairway, which were built out in the 1940s and 1950s.
Olathe: share of homes by decade built
| Decade built | Johnson County homes | Share | Olathe homes | Share |
|---|---|---|---|---|
| 1939 or earlier | 6,759 | 2.6% | 858 | 1.6% |
| 1940s | 6,541 | 2.5% | 590 | 1.1% |
| 1950s | 22,468 | 8.7% | 1,645 | 3.0% |
| 1960s | 23,705 | 9.1% | 2,807 | 5.1% |
| 1970s | 34,318 | 13.2% | 7,466 | 13.7% |
| 1980s | 41,108 | 15.8% | 9,752 | 17.9% |
| 1990s | 43,555 | 16.8% | 10,517 | 19.3% |
| 2000s | 43,758 | 16.9% | 12,641 | 23.2% |
| 2010s | 30,680 | 11.8% | 6,634 | 12.2% |
| 2020 or later | 6,763 | 2.6% | 1,684 | 3.1% |
| Total | 259,655 | 100% | 54,594 | 100% |
What does the age of a house say about its chimney?
It says what the chimney is probably made of. The table below is a general pattern from the trade, not a rule and not part of the housing data. A house can be remodeled, and an inspection is the only way to know what a particular chimney is.
| Era | Typical chimney | What usually needs attention |
|---|---|---|
| Before 1940 | Brick masonry, sometimes with no flue liner | Missing or failed liner, soft mortar, earlier repairs of unknown quality |
| 1940s to 1970s | Brick masonry with clay tile liner | Cracked tiles, worn mortar joints, crown cracks, flashing |
| 1980s to 2000s | Many factory-built fireplaces with metal chimneys inside a framed chase, alongside masonry | Rusted chase covers, worn refractory panels, missing caps |
| 2010s onward | Many direct-vent gas fireplaces | Yearly burner, pilot and vent service |
What did we conclude?
We drew three conclusions, and they are our interpretation of the numbers.
- Most local chimneys are middle-aged. With a county median of 1989, the typical system is 30 to 40 years old. That is old enough for chase covers, crowns and caps to be at the end of their first life.
- The northeast of the county needs more masonry work. The towns built in the 1940s and 1950s have the highest share of brick chimneys with clay liners that have been through 70 or more Kansas winters.
- Olathe leans toward factory-built and gas systems. With almost six in ten homes built in 1990 or later, Olathe calls are more likely to involve a prefabricated fireplace or a gas unit than a full masonry chimney.
What are the limits of this study?
The data counts homes, not chimneys. It does not say which homes have a fireplace, what fuel they burn or what condition any chimney is in. The figures are survey estimates and carry a margin of error. The study describes the housing stock. It does not measure our own jobs, and we have not presented any job data here.
Not sure what kind of chimney your house has? An inspection answers it.
Call (913) 210-6606Case study FAQ
What is the median age of a home in Johnson County, Kansas?
The median construction year is 1989, so the median home is about 37 years old in 2026. The county has 259,655 housing units in the figures used for this study.
Which Johnson County towns have the oldest homes?
The northeast towns built out in the 1940s and 1950s have the oldest housing, including Prairie Village, Mission, Roeland Park and Fairway. Our town pages give the median construction year for each one.
Does an older house always have a worse chimney?
No. Age predicts the type of chimney better than its condition. A 1950s masonry chimney that has been relined and kept dry can be sounder than a 1995 factory-built unit with a rusted chase cover.
Is this case study based on your customers?
No. It is built from public housing data for Johnson County and Olathe. It contains no customer, address or job record, and the conclusions about chimneys are our interpretation.
How do I find out when my house was built?
The Johnson County Appraiser’s property record lists the year built for every parcel, and it is free to search online by address. The year is also on most home inspection reports and listing sheets.
Sources: Housing counts by decade built and median construction year from Point2Homes demographics pages for Johnson County, KS and Olathe, KS, which report U.S. Census Bureau American Community Survey estimates, read October 3, 2026. Percentages are our own arithmetic from those counts. The chimney-type table is our general description of the trade and is not drawn from the housing data.
The age of the house is the first clue. The inspection is the answer.
Open 7 am to 9 pm, seven days a week, in Olathe and 20 surrounding towns.
Call (913) 210-6606