How old are homes in Kirkland, and what does that mean for a deck?
25% of homes in Kirkland's covered ZIP codes were built in 2000 or later and 6% before 1960; the largest group dates to the 1970s.
Homes in Kirkland have a median construction year of 1983, so a deck original to a typical house would now be about 43 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.
That is about the same as King County overall (median 1983). Statewide, the median Washington home was built in 1985. Among the 34 covered Washington communities with Census data, Kirkland ranks #9 for oldest housing. In these ZIP codes, 6% of homes were built before 1960, 37% between 1960 and 1979, 31% between 1980 and 1999, and 25% since 2000 — the single largest group dates to the 1970s.
| Decade built | Homes | Share |
|---|---|---|
| 2020 or later | 1,549 | 4% |
| 2010s | 3,811 | 9% |
| 2000s | 5,193 | 13% |
| 1990s | 5,388 | 13% |
| 1980s | 7,418 | 18% |
| 1970s | 9,381 | 23% |
| 1960s | 6,173 | 15% |
| 1950s | 1,242 | 3% |
| 1940s | 416 | 1% |
| before 1940 | 972 | 2% |
What does Kirkland's climate mean for deck construction?
Kirkland averages about 25 days a year at or below freezing, 3.8 inches of snow and 37.8 inches of precipitation, based on NOAA 1991–2020 normals.
The nearest NOAA climate station with 1991–2020 normals is Seattle Sand Pt Wsfo, about 3 miles away. It records an average of 25 days a year with a low at or below 32°F — relatively few freezing nights. On roughly 24 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 Kirkland 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 3.8 inches in an average year at Seattle Sand Pt Wsfo — so occasional ice is a bigger concern than snow load. Textured boards and good drainage on stairs help on icy mornings.
Kirkland sees about 37.8 inches of precipitation a year, with measurable rain or snow (0.1 inch or more) on about 95 days. Good drainage between boards, clean gaps and a ledger that is properly flashed keep that water from rotting the frame.
Summer heat is mild by comparison — average summer highs near 75°F and only about 2 days a year at 90°F or above — so board color can be chosen mostly on looks.
Which decking material makes the most sense in Kirkland?
For most Kirkland homes, composite or well-maintained wood is the strongest starting point.
Budget, upkeep tolerance and sun exposure on your particular lot still decide the final choice between these options.
| Material | How it handles Kirkland's conditions |
|---|---|
| Pressure-treated pine | Economical; needs regular cleaning and sealing |
| Cedar | Attractive and stable; refinish to keep its color |
| Capped composite | Low maintenance; handles moisture and freeze-thaw well |
| PVC | Lightest and most moisture-proof; premium price |
What kinds of homes are in Kirkland, and how does that shape deck design?
Kirkland has about 41,543 housing units across its covered ZIP codes. 54% are single-family detached homes, 5% are attached homes such as townhouses and rowhouses, and about 41% are in buildings with two or more units. Roughly 61% of occupied homes are owner-occupied.
The mix of detached homes and attached or multi-unit housing in Kirkland means deck projects range from large backyard decks to compact rear decks on narrow lots. Lot size, neighbors' sightlines and any association rules shape the right design.
What deck projects are most common in Kirkland?
Based on the age of Kirkland's housing, the largest group of projects is likely to be replacing or rebuilding aging decks.
- Replacement and major repair: about 22,187 homes (53%) 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 8,803 homes (21%) 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 5,360 homes (13%) 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.
When is the best time to plan a deck project in Kirkland?
Kirkland's milder winters — about 25 freezing nights a year — allow construction through most of the year. Spring and fall are still the busiest seasons, so booking early helps.
Do you need a permit to build a deck in Kirkland?
Often, yes — especially for attached or elevated decks — but the rules are set locally. Check with the building department that serves your address: the municipality, or King County for unincorporated areas.
For Kirkland, WA, ask the permit office whether your deck needs a permit based on its size, height and attachment to the house, which drawings and inspections are required. Statewide code background for Washington is on our state page; local rules change, so the building department remains the authority.
How does Kirkland compare with nearby covered areas?
The closest covered area is Kenmore, about 4.1 miles from the center of Kirkland's covered ZIPs. Its median home was built in 1985, 2 years later than in Kirkland. Kirkland has 9 percentage points fewer detached single-family homes (54% vs. 63%), which changes how many projects are backyard decks versus compact townhouse decks. Owner-occupancy is 61% in Kirkland compared with 69% in Kenmore. Kirkland's covered ZIP codes span about 19 square miles of land with roughly 41,543 homes — about 2,186 per square mile, a typical suburban density where most homes have usable backyards.
| Area | Distance | Median year built | Covered ZIPs |
|---|---|---|---|
| Kenmore | 4.1 mi | 1985 | 1 |
| Medina | 4.7 mi | 1973 | 1 |
| Redmond | 5 mi | 1994 | 2 |
| Woodinville | 6.1 mi | 1987 | 2 |
| Bellevue | 7 mi | 1982 | 5 |
| Bothell | 7.7 mi | 1997 | 3 |
How do Kirkland's covered ZIP codes differ?
| ZIP | Homes | Median year built | Owner-occupied | County |
|---|---|---|---|---|
| 98033 | 18,448 | 1989 | 63% | King County |
| 98034 | 23,095 | 1980 | 59% | King County |
Deck planning checklist for Kirkland homeowners
- Confirm your ZIP code is one of the 2 covered Kirkland ZIPs.
- Find out when your current deck was built and whether it uses pre-2004 treated lumber.
- Probe the ledger, post bases and joist tops for soft wood before planning a resurface.
- Call 811 before any digging so utility lines are marked.

