How old are homes in Johnson County, and what does that mean for decks?
The median home in Johnson County was built in 1989; 14% predate 1960 and 31% were built since 2000.
Johnson County has about 259,655 homes, with a median construction year of 1989 (the Kansas median is 1976). Within our covered ZIP codes — about 256,441 homes — the median is 1989, close to the county as a whole.
Homes in the covered parts of Johnson County have a median construction year of 1989, so a deck original to a typical house would now be about 37 years old — beyond the point where wood framing, fasteners and flashing can be assumed sound.
Many decks from the 1970s and 1980s were built before today's detailed deck provisions appeared in model codes. Common issues on decks of this age include corroded hangers, posts set directly in soil and ledger boards fastened with nails. Replacement is often the better value than repeated repairs.
| Decade built | Homes | Share |
|---|---|---|
| 2020 or later | 6,763 | 3% |
| 2010s | 30,680 | 12% |
| 2000s | 43,758 | 17% |
| 1990s | 43,555 | 17% |
| 1980s | 41,108 | 16% |
| 1970s | 34,318 | 13% |
| 1960s | 23,705 | 9% |
| 1950s | 22,468 | 9% |
| 1940s | 6,541 | 3% |
| before 1940 | 6,759 | 3% |
Which Johnson County communities have the oldest and newest homes?
Among covered Johnson County communities, Prairie Village has the oldest housing (median 1957) and Stilwell the newest (median 2002).
Oldest housing: Prairie Village (1957), Mission (1959) and Edgerton (1978). In these communities, expect retrofit decks on older houses and aging decks that need structural inspection, ledger and flashing upgrades, or replacement. Newest housing: Stilwell (2002), Gardner (2002) and Olathe (1994). Here, projects lean toward enlarging builder-installed decks, adding stairs and railings, and upgrading to low-maintenance boards.
How does Johnson County's climate affect deck building?
Covered parts of Johnson County average about 98 days a year at or below freezing (NOAA 1991–2020 normals, 5 stations). Across the covered communities, nearby stations range from about 93 to 128 freezing days a year, so conditions differ noticeably between Johnson County's higher, more rural areas and its urban core.
The nearest NOAA climate station with 1991–2020 normals is Olathe 3e, about 3 miles away. It records an average of 98 days a year with a low at or below 32°F — a moderate number of freezing nights. On roughly 77 of those days the temperature climbs back above freezing, so water in wood, soil and gaps between boards repeatedly freezes and thaws.
Frost is less severe in Johnson County than in northern states, but footings still have to meet the local frost-depth requirement, and freeze-thaw cycles are enough to work loose nails and open checks in unsealed wood.
Snowfall is light — about 13.8 inches in an average year at Olathe 3e — so occasional ice is a bigger concern than snow load. Textured boards and good drainage on stairs help on icy mornings.
Precipitation averages about 40.7 inches a year, falling on about 65 days with 0.1 inch or more — wet enough that drainage and flashing still matter, but dry spells also let wood surfaces dry out and check in the sun.
Average summer highs reach about 86°F, and around 34 days a year top 90°F. On a deck with full afternoon sun, dark composite can get uncomfortable on those days, so test samples in the sun before choosing a color.
What deck projects are most common in Johnson County?
Based on the age of Johnson County's housing, the largest group of projects is likely to be replacing or rebuilding aging decks.
- Replacement and major repair: about 118,981 homes (46%) were built between 1970 and 1999, the age group whose original or early add-on decks are most likely to have worn-out framing, connectors and boards.
- Retrofit decks on older homes: about 59,473 homes (23%) predate 1970. Here the priority is confirming that add-on decks are properly attached — or rebuilding them freestanding — before any cosmetic work.
- Upgrades and expansions: about 37,443 homes (14%) were built since 2010. Their decks are usually sound but small or builder-grade, so enlarging the deck, adding stairs and switching to composite or upgraded railings are common.
Which Johnson County communities do you serve?
12 communities in Johnson County have covered ZIP codes. Only the ZIPs listed are covered.
| Community | Covered ZIPs here | Median year built | Detached homes |
|---|---|---|---|
| Overland Park | 66204, 66207, 66210, 66212, 66213, 66214, 66221, 66223, 66224, 66251 | 1989 | 57% |
| Shawnee | 66203, 66216, 66217, 66218, 66226 | 1985 | 74% |
| Lenexa | 66215, 66219, 66220, 66227 | 1994 | 57% |
| Leawood | 66206, 66209, 66211 | 1988 | 66% |
| Mission | 66202, 66205 | 1959 | 67% |
| Olathe | 66061, 66062 | 1994 | 73% |
| De Soto | 66018 | 1992 | 71% |
| Edgerton | 66021 | 1978 | 92% |
| Gardner | 66030 | 2002 | 69% |
| New Century | 66031 | n/a | n/a |
| Prairie Village | 66208 | 1957 | 91% |
| Stilwell | 66085 | 2002 | 77% |
What decking material works best in Johnson County?
Capped composite is a strong default for Johnson County because about 77 freeze-thaw days a year are hard on unsealed wood.
66% of Johnson County's homes are detached single-family houses and 8% are townhouses or other attached homes; 69% of occupied homes are owner-occupied. With mostly detached homes, wood remains a practical lower-cost option for homeowners willing to clean and seal on schedule.
Who issues deck permits in Johnson County?
It depends on where you live: incorporated cities and towns in Johnson County usually run their own permit offices, while unincorporated areas are typically served by Johnson County.
Kansas does not enforce a single statewide residential building code; cities and counties adopt and enforce their own. Contact your city's building or permitting office. Before work starts, confirm with the building department for your exact address whether a permit is required, what drawings and inspections it involves, and whether an HOA must approve the design.