How old are homes in Glen Ellyn, and what does that mean for a deck?
12% of homes in Glen Ellyn's covered ZIP code were built in 2000 or later and 30% before 1960; the largest group dates to the 1960s.
Homes in Glen Ellyn have a median construction year of 1970, so a deck original to a typical house would now be about 56 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 makes Glen Ellyn's housing 8 years older than DuPage County as a whole, where the median home was built in 1978. Statewide, the median Illinois home was built in 1971. Among the 102 covered Illinois communities with Census data, Glen Ellyn ranks #42 for oldest housing. In this ZIP code, 30% of homes were built before 1960, 39% between 1960 and 1979, 18% between 1980 and 1999, and 12% since 2000 — the single largest group dates to the 1960s.
| Decade built | Homes | Share |
|---|---|---|
| 2020 or later | 55 | 0% |
| 2010s | 517 | 4% |
| 2000s | 1,237 | 8% |
| 1990s | 1,252 | 8% |
| 1980s | 1,423 | 10% |
| 1970s | 2,835 | 19% |
| 1960s | 2,964 | 20% |
| 1950s | 2,148 | 15% |
| 1940s | 448 | 3% |
| before 1940 | 1,855 | 13% |
What does Glen Ellyn's climate mean for deck construction?
Glen Ellyn averages about 144 days a year at or below freezing, 24.3 inches of snow and 41.1 inches of precipitation, based on NOAA 1991–2020 normals.
The nearest NOAA climate station with 1991–2020 normals is Lisle-Morton Arboretum, about 4 miles away. It records an average of 144 days a year with a low at or below 32°F — a long, hard freezing season. On roughly 98 of those days the temperature climbs back above freezing, so water in wood, soil and gaps between boards repeatedly freezes and thaws.
For Glen Ellyn, that means footings must bear below the locally required frost depth to avoid heaving, and wood surfaces should be kept sealed so absorbed water doesn't split boards over winter. Synthetic decking tolerates freeze-thaw well but still needs the manufacturer's expansion gaps.
Average snowfall near Glen Ellyn is about 24.3 inches a year (Wheaton 3 Se). That's enough that shoveling and ice-melt choices affect deck surfaces, and stair treads benefit from good texture and drainage.
Glen Ellyn sees about 41.1 inches of precipitation a year, with measurable rain or snow (0.1 inch or more) on about 76 days. Good drainage between boards, clean gaps and a ledger that is properly flashed keep that water from rotting the frame.
Average summer highs reach about 83°F, and around 17 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.
Which decking material makes the most sense in Glen Ellyn?
For most Glen Ellyn homes, capped composite is the strongest starting point because about 98 freeze-thaw days a year are hard on unsealed wood.
Budget, upkeep tolerance and sun exposure on your particular lot still decide the final choice between these options.
| Material | How it handles Glen Ellyn's conditions |
|---|---|
| Pressure-treated pine | Economical; needs sealing to resist freeze-thaw splitting |
| 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 Glen Ellyn, and how does that shape deck design?
Glen Ellyn has about 14,734 housing units across its covered ZIP code. 71% are single-family detached homes, 6% are attached homes such as townhouses and rowhouses, and about 24% are in buildings with two or more units. Roughly 81% of occupied homes are owner-occupied.
The mix of detached homes and attached or multi-unit housing in Glen Ellyn 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 Glen Ellyn?
Based on the age of Glen Ellyn's housing, the largest group of projects is likely to be retrofitting or rebuilding decks added to older homes.
- Retrofit decks on older homes: about 7,415 homes (50%) predate 1970. Here the priority is confirming that add-on decks are properly attached — or rebuilding them freestanding — before any cosmetic work.
- Replacement and major repair: about 5,510 homes (37%) 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.
- Upgrades and expansions: about 572 homes (4%) 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 Glen Ellyn?
With about 144 freezing days a year, the building window in Glen Ellyn is compressed. Design, drawings and permits are usually handled in winter so footings can go in as soon as the ground allows in spring, and finishes like stain are applied before nights turn cold in fall.
Do you need a permit to build a deck in Glen Ellyn?
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 DuPage County for unincorporated areas.
For Glen Ellyn, IL, 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 Illinois is on our state page; local rules change, so the building department remains the authority.
How does Glen Ellyn compare with nearby covered areas?
The closest covered area is Lombard, about 2.4 miles from the center of Glen Ellyn's covered ZIPs. Its median home was built in 1971, 1 years later than in Glen Ellyn. Glen Ellyn has 13 percentage points more detached single-family homes (71% vs. 58%), which changes how many projects are backyard decks versus compact townhouse decks. Owner-occupancy is 81% in Glen Ellyn compared with 71% in Lombard. Glen Ellyn's covered ZIP code span about 11 square miles of land with roughly 14,734 homes — about 1,339 per square mile, a typical suburban density where most homes have usable backyards.
| Area | Distance | Median year built | Covered ZIPs |
|---|---|---|---|
| Lombard | 2.4 mi | 1971 | 1 |
| Wheaton | 2.9 mi | 1976 | 2 |
| Glendale Heights | 3.8 mi | 1978 | 1 |
| Villa Park | 4.5 mi | 1962 | 1 |
| Winfield | 4.8 mi | 1986 | 1 |
| Carol Stream | 4.9 mi | 1984 | 1 |
Deck planning checklist for Glen Ellyn homeowners
- Confirm your ZIP code is 60137, the covered Glen Ellyn ZIP.
- Find out when your current deck was built and whether it uses pre-2004 treated lumber.
- Ask what footing depth your building department requires for frost.
- 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.

